Multiport fuel injection systems deliver the ultimate in adjustability and tuning capability to extract maximum performance from an engine for a particular application. So if you desire the ultimate in tuning and flexibility for your fuel system, a custom-designed MPFI system is certainly for you. Among the many MPFI systems on the market, the Holley Dominator proved to be a leader.
This Tech Tip is From the Full Book, EFI CONVERSIONS: HOW TO SWAP YOUR CARB FOR ELECTRONIC FUEL INJECTION . For a comprehensive guide on this entire subject you can visit this link:
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Most engine builders have a favorite throttle body, favorite injector brand, favorite ECU brand, etc. Over the years, they’ve refined their formula to deliver results that are predictable in performance and offer them the utmost in flexibility in tuning. Pull any tuner aside and ask them what makes or breaks a particular EFI combination and they will tell you it’s the software. The software simply must be able to allow them the control they desire.
For the past three SEMA shows, I’ve paid very close attention to the EFI systems available. The Holley Dominator system continues to be a real stand-out. As this book became a reality, I definitely wanted to include it, but first it had to pass the “Bill” test. Bill Surin owns the Olds in this chapter.
Bill is a hard-core enthusiast who lives and breathes by the time slip. He assembles his own engines and does his own tuning and he’s quite good at it. He’s got the largest selection of Holley carburetor parts of anyone I know and is constantly tuning to achieve the best performance in the current weather. He’s also been talking for a while about converting to MPFI, especially since he’s seen firsthand how well the TBI setup on my Olds performs.
Bill’s Olds was featured in my book Automotive Electrical Performance Projects, so you may recognize it. In that book, we optimized the performance of the charging system and correctly wired the relocated battery. Once this was complete, we were then able to optimize the performance of the electric fans and headlights.
Define Your Objective
Before selecting components for a project of this scale, it’s important to define what you intend to accomplish. Holley offers two ECUs that can be used as the basis for a custom MFPI system: the HP and the Dominator. Both use the same software, same harnesses, have a similar feature set, and are compatible with the following:
- TBI installations (single or dual throttle body)
- MPFI installations
- GM LS conversion installations, compatible with EV6-style injectors and coil-on-plug ignition systems
- GM HEI/Ford TFI/CD-style/Holley DIS (distributorless ignition systems)
- Holley’s water/methanol injection driver and associated components
- Holley’s nitrous-oxide solenoid driver
- Traction control via Davis Technologies’ Holley Module
The Dominator ECU adds the following features:
- Dual oxygen-sensor inputs (theHPECUhasasingle oxygen-sensor input)
- Built-incontrolforGM4L60E and 4L80E automatics
- GMdrive-by-wire compatibility (pedal and throttle body)
- 12injectordrivers,capable of driving up to 24 low- or high-impedanceinjectors(the HP ECU has 8 injector drivers)
- Morethan50user-configurable inputs/outputs (the HP ECUs has8user-configurableinputs/ outputs)
The main reasons we chose the Dominator ECU for Bill’s Olds are that Bill wants to be able to add a singlestageofnitrous(dry)andhave the ECU manage it: add the nitrous progressively (via one of the four spare injector drivers), richen the mixture accordingly, and retard the timing accordingly. Also, Bill may add an overdrive transmission later.
If your priorities don’t include the above, you can use the HP ECU for a similar MPFI installation and save a few bucks.
The main difference between the Holley MPFI system and every other system previously discussed is that you choose the components specific to your particular application, thereby assembling an MPFI system from scratch. Holley has done a good job of making this process painless via the EFI Selection Chart on their website. In short order, Bill and I were able to determine the parts required.
Here are the options we had available:
- ThrottleBody(4500or4150 flange)
- Main Harness
- Injector Harness
- Ignition Harness
- TransmissionControl(if using a GM 4L60/65/70/80/55E automatic transmission)
- GMDrive-By-WireHarness(if applicable)
- AuxiliaryHarness(tofacilitate connections to INPUTS and OUTPUTS) • Fuel Injectors
- Sensors(oxygen, MAP,CTS,IAT, fuel pressure, oil pressure)
- Cam Trigger (optional here; required for sequential fuel injection)
- DistributorlessIgnitonSystem (DIS; optional)
As you can see, this is a substantially different system from the MSD Atomic System discussed in Chapter 5. You have so many more options at your disposal;you can truly assemble a system that offers you exactly what you’re after in the way of operation, performance, and tuning.
We were faced with a challenge in the parts selection process because Bill’s Olds runs E85 and not gasoline. E85 has a different stoichiometric ratio (9.8:1) than gasoline (14.7:1). In addition, E85 has a lower energy content than gasoline, which means quite simply that a given mass of E85 has less power potential than the same mass of gasoline. So, we knew right away that we needed to supply a greater mass of E85 to the engine than with gasoline. This affected the selection of fuel system components, including the fuel injectors.
After taking all variables into consideration, we chose the components for this installation (see top chart).
In addition, Holley recommended some fuel components for our application (see bottom chart).
Youalsoneedalaptopcomputer to communicate with the ECU. You don’t need a laptop with the latest processor, a lot of RAM, or the latest operating system. Windows XP works fine, as does Windows 7. However, Windows7requiresafewsimple tweaks to allow the datalogger and other write functions to work.
You need to document your current engine timing setup before removing the carburetor for an installation like this one. Specifically, you need to know:
- Base Timing: Disconnect any vacuum advance, plug the vacuum port, read at idle
- IdleTiming:Reconnectanyvacuum advance, read at idle
- At what RPM the timing is all in
You may also want to look at the timing at cruise RPM to see just how much timing is in the engine when you’re cruising down the freeway in high gear. Document everything and keep the information in a place where you won’t lose track of it. You will need it when setting up your base tune later in the project.
For Bill’s combination, he runs an MSD Pro-Billet distributor with no vacuum advance and has the distributor locked out, bypassing the centrifugal advance. Bill determined that his combination works best with 31 degrees of timing both on the engine dyno and chassis dyno. Finally, he uses the Start Retard function of an MSD Digital-6 CD-style ignition box to retard 20 degrees of timing during start. All of these parts are fully compatible with the Holley system.
Holley Dominator System Installation
An installation such as this one can be intimidating. By separating the installation into stages, you can simplify the process and ensure you complete each stage fully before proceeding to the next. Here is an overview of the four installation stages:
Before beginning, I strongly encourage you to plan accordingly. This is not a project that you can do in a weekend. To achieve the results a system like this is capable of, it’s imperative to spend the effort required to perform each of the steps to the best of your ability. If in doubt, call in a friend to help before proceeding to the next step.
Stage One: Pre-Installation
You need to complete the following steps to correctly install the software, oxygen sensor bungs, oxygen sensors, and fuel injectors. In order to maximize functionality and performance of the system, you must perform or have a professional-quality installation performed.
1. Load the Software
The very first thing you want to do is to load the Holley EFI software on your laptop and desktop PC. This is because Holley does not include any printed instructions with the Dominator EFI systems and you’re going to want to print out several documents(likelyfromyourdesktop PC). Holley includes a CD-ROM (with the software on it) with the ECU, but you may elect to check the Holley EFI website for the latest version of the software before installing it from the disc(holleyefi.com>TECHNICAL> Resource Documents & Downloads > Fuel Injection).
Once you have the software loaded, open it. When the CHOOSE OPENING OPTION menu comes up, click on Cancel at the bottom of the window. All of the instructions are located in the Help Menu of the software.
- Click on Help on the toolbar at the top
- Select Contents
- Expand the READ FIRST! HELP/ Instructions Overview, click on the document of the same name and print it
- Expand the Quick Start Guide, click on the document of the same name and print it
- Expand the Step-By-Step Beginners Tuning Guide, click on the document of the same name and print it
- Expand the Wiring Manual and Diagrams, click on the document of the same name and print it
I recommend that you print the pages two-sided if your printer allows it, three-hole-punch them all, and put them in a binder for easy reference if you have questions along the way. (The Contents section of the Help menu has all of the documents you may need for a particular installation.)
It’s also not a bad idea to read through these documents before beginning the installation so that you can familiarize yourself with the big picture of how the system works and the terminology that Holley uses with the system and software.
As you perform the installation of various components, you may also elect to three-hole-punch any included instructions and put them in your binder.
2. Install Fuel Injectors
Many enthusiasts have a professional shop complete this work. We did. In fact, we had a shop install the fuel injectors on the aluminum manifold because neither Bill nor I is a welder. If you’re an accomplished welder and an expert TIG welder, you may elect to tackle this part on your own.
We farmed this job out to local fuel injection specialist Bob Ream. He took our bone-stock Edelbrock Victor manifold and welded bungs in the intake runners for the injectors. In addition, he cut fuel rails to length, constructed mounts for them to attach to the manifold, and threaded the ends for -8 straight-cut fittings. His pricing was very reasonable and the end result looks quite good.
After Bob completed this work, Bill spent an afternoon and evening with a die grinder and port-matched the intake runners to the Edelbrock cylinder heads on the 455 to ensure maximum airflow between the manifold and cylinder head.
3. Install Oxygen Sensor Bungs
Bill has more oxygen sensor bungs in the headers on his Olds thananythreepeopleIknow.Long before we started this project, he had already paid a local exhaust shop to install oxygen bungs in each primary and two in each collector of each header: that’s 12 in all. Bill had plans to purchase an Innovate LM-2 dual-channel wideband A/F meter and wanted to take advantage of all the data acquisition the unit offers.
Stage Two: Electrical and Fuel Systems
This stage of the project is easily the most arduous and time consuming. It is also the most critical because the electrical and fuel systems collectively determine the performance potential of the installation.
1. Optimize Electrical System
You need to optimize the charging system so that you can accommodate the additional current required by an EFI system. As I mentioned earlier, we had already done this in Bill’s Olds. However, I suspected we were right at the maximum output Bill’s alternator was capable of making at idle (87 amps). Bill has since converted his Olds to run on E85, upgraded to a larger Fuelabs multi-speed pump, and added the Innovate LM-2 dual-channel wideband A/F meter and numerous oxygen sensors. I suspected this was the tipping point for the existing 12SI alternator, as Bill noted voltage was in the low-13s on his dash-mounted volt meter when cruising around.
We know we have to upgrade the alternator first. Because the charge lead and return path were already upgraded, we just need to swap out the alternator.
However, the underdash of Bill’s car has needed attention since we met. We can’t even start on this project before addressing this and honestly, I had not been looking forward to fixing this mess despite Bill’s repeated attempts at bribing me to do so. It was time to pay the piper, so I bit the bullet and got busy.
Correcting this took me the better part of an entire weekend. The benefit of owning an auto electric supply company is that I have parts on hand for a job like this.
If you have a similar mess under the dash of your prized possession and want to convert that to a sensible, orderly, and safe installation, I illustrate the process fully in Automotive Electrical Performance Projects. This process is lengthy and outside of the scope of this book.
We chose a BILLET-TECH alternator from Mechman in the black hard-anodized finish for Bill’s Olds. Based on our needs, they recommended the 170A Model, rated to deliver 140 amp sat idle(800 engine RPM) and 170 amps at cruise (2,000 engine RPM)with a standard 3:1 pulley ratio. I was pleasantly surprised when I noticed that the BILLET-TECH 170A output at cruise RPM was actually measured at 1,800 engine RPM according to the sheet provided with it. It should be perfect.
Using the methods outlined in Chapter 2,here are the steps and our readings:
Record the resting voltage of the battery with the engine not running: 12.5 volts.
Start the engine and bring the vehicle to operating temperature.
Turn on all of the accessories, including the high-beam headlights, A/C, electric cooling fan(s),audio system at a common listening level, etc.
After the engine has reached operating temperature, record the voltage at the battery: 13.1 volts.
Record the output current of the alternator: 82 amps.
The first problem here is that our running voltage is below 13.4 volts, which confirms the Fuelabs pump, the Innovate LM-2, and the array of oxygen sensors were indeed the tipping point for the existing 12 SI alternator. Output current dropped from 87 to 81 amps as a result of this drop in voltage.
For fun, I put my Fluke i410 current clamp around the battery positive cable while the vehicle was running (separate from the charge lead in this installation), and recorded only 1 amp of current flowing back into the battery at idle. This explains the lower-than-ideal 12.5 resting voltage of the battery.
There’s no need to load the alternator with the carbon pile load in the Snap-on analyzer as we know it isn’t big enough.
Typically, an alternator swap like this is a piece of cake. However, Bill’s Olds has a front engine plate and we had to modify it slightly to accommodate the larger output stud and larger regulator plug.
While we were installing the alternator, we put my trusty Schumacher battery charger on the battery to charge it fully(this is outlined fully in the instructions included with the alternator).
Once the BILLET-TECH alternator was installed, we started the engine, allowed it to reach operating temperature, and then again turned on all of the accessories.
Record the voltage at the battery: 14.7 volts.
Record the output current of the alternator: 90 amps.
Load the alternator with the carbon pile load in the Snap-on analyzer to determine how much output the alternator is capable of at 800 engine RPM.
Record the voltage at the battery: 11.9 volts.
Record the output current of the alternator: 139 amps.
Now that’s not bad, considering the distance between the alternator and battery is approximately 20 feet. We fell only 2 amps short of the 141 amps reported by Mechman on the test certificate included with the alternator. This is to be expected in an installation like this where the battery is so far from the alternator. This certainly illustrates the importance of using the correct-size charge lead (2 AWG in this Olds) and a proper return path for the alternator (also 2 AWG).
Again, our efforts paid off and we got a substantial improvement.Let’s consider our results as percentages (see chart below).
Now that the charging system is in order, we can move on to the fun stuff. In addition, we are able to rest easy knowing that the newly installed alternator is capable of making all the power our new components will ever need. This ensures they live a long and healthy life.
2. Install Fuel System
Bill’s Olds has always had a solid fuel system, for a carbureted application. He removed the factory tank, had a baffled sump installed with a pair of -8 bungs (one for the outlet and one for the return), and he uses the factory vent. The fuel lines are -8 Aeroquip push-locks for the feed and return. An Aeromotive 100-micron filter with shut-off valve, Fuelabs multi-speed fuel pump, and Mallory regulator rounded out the carbureted fuel system. It is basic, but very functional. We elected to retain the Aeromotive pre-filter as the shut-off valve is handy, especially considering that we could simply turn it off and make all of the upgrades you see here without draining the tank.
Plumbing a fuel system that includes fuel rails is really not that difficult. There are two popular methods. We chose the simpler of the two for Bill’s Olds(see Figure6.17),which is illustrated in the installation manual included with the Holley fuel pumps. The other is illustrated in the sidebar “Plumbing High-Horsepower Applications” on page 106.
I mounted the Holley fuel pump to the frame rail, using the bracket I had previously made for the Fuelabs fuel pump. In addition, we re-used several of Bill’s existing fuel lines. Hey, sometimes you do get lucky! It was necessary to purchase numerous -12 O-ring to -8 AN fittings, -8 O-ring fittings, and -8 straight-cut fittings for this installation.
The Holley 12-1400 and 12-1800 fuel pumps are somewhat unusual. Each has two pumps in a common housing and they share the inlet and outlet. Only one pump is required for cruising, and both are required for WOT in an effort to maintain fuel pressure. Therefore, each has independent power and ground leads for each of the internal pumps. I connected each of the internal pumps to its own 30-amp relay as shown in the installation manual. In addition, I fed each pump with 10 AWG and soldered all connections for the best performance and reliability.
Bill already had a pair of Bosch 30-amp relays mounted in sockets for the Fuelabs pump, each connected to the three-position ATC fuse panel we installed in his car in Automotive Electrical Performance Projects. Even though the instruction manual included with the 12-1400 pump suggests wiring each of the internal pumps with 12 AWG, I elected to use 10 AWG to further minimize voltage drop, which included re-wiring the relay sockets with 10 AWG. For now, I’ve wired the fuel pump so that it can be controlled directly from Bill’s dash-mounted fuel pumps witch(in Chapter 7,we automate it).
We mounted the Holley regulator in nearly the same position the Mallory regulator had occupied, and the Holley 10-micron post-filter just above that on the inner fender. The component location complies with NHRA rules. Since the inner fender on the Olds is plastic,we used 1/4-inch hardware (bolts, washers, lock washers, nuts) to mount the components securely.
We also connected a brass T and a brass 90-degree elbow (both 1/8-inch NPT) to the fuel-gauge port on the regulator to provide locations for the Holley fuel pressure transducer as well as the transducer that came in the new Auto Meter electric fuel pressure gauge (see the sidebar “Monitoring and Data logging Fuel and Oil Pressure” on page 105 for more details).
We fabricated the remaining fuel lines to and from the fuel rails. This really is a simple fuel system. At this point, the fuel system is completed and we’re ready to move on to Stage Three.
Stage Three: Holley Dominator Components
Now that the electrical system has been appropriately upgraded and the fuel system is installed, it’s time to install the throttle body, sensors, and wiring harness. In addition, we need to interface the ignition system and install the ECU.
1. Install Throttle Body and Linkage
Okay, I admit it. Immediately upon receiving the actual components, Bill and I took about seventeen seconds to get the intake manifold and throttle body unboxed and mated together. Let the cell phone picture blasts begin. After we got that out of our system, the throttle body went back into its box and now it’s finally time to install it for real.
At this point, it’s really hard to not get a little bit excited as we’re on the downhill stretch. We’re already thinking about how folks are going to react when they see this new jewelry under the hood at the next car show. Time for round two of cell phone picture blasts.
That was the easy part. Now it was time to get the linkage dialed in and this took a few hours to get right. We ended up fabbing a short bracket outof1/4-inch-thick flat-steel stock to mount the Holley throttle cable linkage bracket to. The challenge is to get the linkage to work properly without binding, permit WOT, and fit under the air cleaner assembly. Patience here is definitely a virtue.
2. Choose Component Location
Before mounting any of the other components or sensors, you need to first determine their installed locations. Specifically, you want to choose a location for the ECU, each of the sensors, and lay the main harness loosely in the vehicle to be sure that everything reaches.
When choosing a location for the ECU, be sure to locate it away from sources of noise, such as ignition system components and their harnesses. In addition, it’s preferable not to have a big length of “extra” harness that you’ve got to bundle somehow as a result of locating the ECU too close to the engine.
I’ve often mounted ECUs behind the dash on the passenger side, which solves both problems, but in this Olds that’s quite a busy (and electrically noisy) location. In addition, the Dominator ECU is the largest ECU I’ve yet seen so it requires a fair chunk of real estate and should have good airflow around it. We elected to mount it under the hood. Specifically, we chose to locate it at the front of the passenger-side inner fender. This offered plenty of room, as well as the ability to route the main harness up through the area between the inner fender and fender, totally out of sight.
According to the thick red warning sheet wrapped around the ECU, Holley cautions us not to mount the ECU in such a way that its chassis is “shorted” to the vehicle chassis in any way, which made the plastic inner fender even more attractive. The ECU has nylon bushings in each of the mounting tabs and includes stainless mounting hardware to prevent an electrical connection between the chassis of the ECU and the chassis of the vehicle, even when mounting it to a metal panel.
Holley even includes a weathertight USB cable that’s plugged into the ECU when mounted under the hood and then routed through the firewall. I verified that it was long enough before settling on this location.
Before choosing locations for each of the sensors, I recommend that you have a good look at all harnesses for the ECU and familiarize yourself with how much length each of the sensor sub-harnesses offers you. I mention this because you most likely prefer to avoid extending any of these and you may be able to determine locations for each of the sensors that work perfectly with the harness as it is. In some cases, there is one location for a given sensor. In other cases, such as with CTS, IAT, and MAP sensors, you may have multiple locations to choose from.
After we settled on a location for the ECU and each of the sensors, I laid the harness over the passenger-side fender and routed it along the firewall and to the intake manifold to be sure that everything reached. In this installation, I had to extend a few of the sensor sub-harnesses, which was not difficult, so don’t fret if you need to do this.
3. Install Sensors
We’ve already installed the pressure transducers for the fuel pressure input of the ECU and the Auto Meter fuel pressure gauge. Next in line was the crank trigger. The Holley big-block Chevy Crank Trigger Kit required a few simple modifications to work on the Olds 455. Bill runs an ATI Olds balancer, which has a bolt pattern for a big-block Chevy crank pulley. Even so, it was still necessary to modify parts of the kit slightly to achieve a good fit. A qualified machine shop should perform this work.
Bill recruited Precision Research to help make the installation a snap. Specifically, Precision Research opened up the centering adapter by a few thousandths so that it fit perfectly around the harmonic balancer locating pilot. They also made a .090-inch-thick aluminum spacer that fits between the trigger wheel and the balancer.
The spacer was installed first, then the trigger wheel, and the centering adapter. They netted a perfect fit that required no modification to the balancer or lower crankshaft pulley. In addition, this Olds has a front engine plate so mounting the pickup assembly was a bit unique. Sure, the Chevy guys get all the cool parts, but that didn’t stand in our way here.
We located the CTS in the stock thermostat housing, which had a plugged 3/8-inch NPT threaded hole ready to accept the sensor. Before removing such a plug, drain the coolant in the radiator to below its level. You only forget to do that once . . .
We located the transducer for the oil pressure input of the ECU just below the transducer Bill had already mounted for his Auto Meter electric oil pressure gauge. Thankfully, Bill had installed the brass T when installing the other sending unit many years ago, so all we had to do was remove the plug and thread the transducer in. Simple.
We located the MAP sensor on the firewall, just under the cowl. When mounting a MAP sensor, you should always mount it in such a way that the barb points downward.
We mounted the IAT sensor in the air cleaner assembly mainly because Bill intends to use nitrous via a plate system. The IAT can also be mounted in the intake manifold. Holley labels this connector MAT (manifold air temperature). In boosted installations, it’s preferable to mount the IAT in the intake manifold because the temperature of the ambient air rises when the supercharger compresses the air. Nitrous is just the opposite so we wanted to keep the IAT out of the manifold for now. The Edelbrock Victor manifold has a 3/8-inch NPT threaded boss in the rear if we elect to change this in the future as Bill perfects his nitrous tune.
As I discussed earlier, Bill had a spare bung in each collector for the oxygen sensors. So installing them was a snap.
Based on the location for the ECU and for each of the sensors, I had to extend the following sub-harnesses: fuel pressure, CTS, oil pressure, and MAP.
This is really a simple process. I began by unwrapping the sensor pigtail of the main harness, untaping the gathered wires, and separating them so that I could easily work on each individually. I extended each with 18 AWG GPT, which is one size larger than the size used in the harness.
After each of the sub-harnesses was extended, I re-wrapped the harness with split-braide tubing.
4. Install Wiring Harnesses
I began by installing the injector harness. To keep the connections clean and out of sight, I spun each of the injectors around so that their plugs faced the throttle body. I routed the injector harness into the center of the manifold, under the runners, from the rear to keep it out of sight as much as possible.
Then I installed the crank sensor harness. Now that the injector harness, crank sensor harness, and all of the sensors have been installed, we can begin installing the main wiring harness.
The injector harness simply plugs into the mating connector on the main harness.
The crank sensor harness plugs into the mating connector on the main harness.
Then I pugged in the TPS and IAC on the throttle body, and each of the sensors. I routed the oxygen sensor harness in the main ECU harness across the top of the bellhousing to the oxygen sensor on the driver’s side;it was the perfect length.
Next up was the auxiliary harness for the passenger-side oxygen sensor. It also was the perfect length. CAUTION: Do not plug the oxygen sensors into the harness at this time. They must be set up in the ECU first or they will be damaged when you power up the ECU.
The included power harness was just a few feet short, given the location we chose for the ECU and the fact that the Olds has a rear-located battery, albeit on the same side as the ECU. I extended the harness by 5 feet with 10 AWG TXL.
I also elected to remove the ATC fuse holder from the ECU end of the power harness and relocate it to the rear of the vehicle near the battery for safety reasons. For now, leave the fuse out of the fuse holder.
This leaves only the following “loose wires,” as Holley refers to them, to connect:
I connected the black wire to the frame on the same side of the frame where the battery is grounded. This ground should be all alone, with no other grounds tied to it.
I routed the other four wires through the firewall and into the passenger compartment. I passed them through a plastic snap bushing to protect them, of course.
The red/white wire connects to a +12V switched source. I connected that to one of the fused switched outputs on the power panel. (Any power wire that passes through the firewall must be fused with a foot or so of its source of power. Keep that in mind if you elect to connect this wire to the ignition switch, etc.) For now, leave the fuse out.
I routed the green wire to the switch panel in Bill’s dash. He’s had this same switch panel for nearly 20 years, butIhelped him to wire it correctly. I always recommend using the fuel pump output of the ECU because it primes the system when the key is turned to run position. In addition, the Holley software allows you to adjust the length of time the fuel pump primes. That’s cool. Even though we’ve already installed a pair of 30-amp relays for the Holley Dominator fuel pump, they’re switched positively, so the output from the ECU is correct for us (see Figure 6.21).
You must be able to power the fuel pump directly (not via the ECU’s fuel pump output) to check the fuel system for leaks and to set the fuel pressure. In Bill’s Olds I left the fuel pump switch wired as it was (manual), for now, for this reason.
5. Interface ECU to Ignition System
This is really pretty simple if you’re running a stand-alone CD-type ignition box. The Dominator ECU sends a trigger out that is connected to the points input of the ignition box. Look at it like this: the crank trigger tells the ECU where the crankshaft is. The ECU triggers the ignition box based on the location of the crankshaft, which coincides with the location of the rotor in the distributor. Remember that the rotor makes one full rotation for every two rotations of the crankshaft. It was as simple as connecting the white wire from the ECU to the white wire of the MSD Digital 6AL. Done.
6. Install ECU
By this point, Bill was foaming at the mouth: “Dude, plug that in and let’s start it!” Not so fast, we’ve got a ways to go yet. Before mounting the ECU, you need to install the Holley EFI software on the laptop you intend to use with the vehicle (if you have not done so already), including the USB bridge. Then establish a connection between the laptop and the ECU via the included USB cable.
This step is imperative so that you can communicate with the ECU from your laptop via the USB. This process is simple, can be done on the bench without the ECU powered up, and is outlined clearly in the instructions included with the ECU.
We used the stainless hardware Holley included to mount the ECU to the inner fender. It was far easier than I thought it would be.
Stage Four: Get It to Run
Before starting the Olds we need to flush the fuel system, set the fuel pressure, build a base tune, load the tune into the ECU, and perform a few final calibrations. Each of these final steps is critical to ensure the Olds fires up and runs correctly.
1. Flush System and Set Fuel Pressure
Anytime you assemble a fuel system from scratch, as we did here, you want to blow out each assembled line with compressed air as you’re assembling them. Even then, it’s always a great idea to flush the lines with some fuel before final assembly. Before doing so, ensure that all fittings are tight from tank to pre-filter, pre-filter to pump, pump to post-filter, and at the outlet of the post-filter.
Undo the fitting for the line at the inlet to the fuel rails and let this line hang free.
If your pre-filter has a shut-off valve, like the Aeromotive filter in this installation does, be sure that it is in the FLOW position before proceeding.
Also, install the fuse for the fuel pump at this time.
Have a helper hold the free line in a catch can and manually turn on the fuel pump to flush some fuel into the catch can, just enough to flush any debris out of the lines. In the Olds it was easy to power up the fuel pump manually via the dash-mounted switch with the ignition key in the RUN position.
Then reinstall the fitting on the fuel rail and remove the return line from the other fuel rail to the regulator (at the regulator).
Now that the fuel system has been flushed, reconnect any disconnected lines and tighten all fittings appropriately.
Power the fuel pump back up to pressurize the system and check all fittings for leaks. Address any leaks at this time.
After you’ve verified the system is leak free, power the fuel pump and set fuel pressure via the dash-mounted gauge.You can do this via an external fuel pressure gauge such as the Fluke (illustrated in Chapter 5). With this Holley system, we set fuel pressure to 43 psi per Holley’s instructions.
Remove the fuse for the fuel pump before proceeding.
2. Build or Adjust a Base Tune
It’s time to build the tune you will load into the ECU. You have two choices: build a base tune from scratch or tweak one of the base tunes Holley has provided.
If you’re an advanced tuner, you may elect to build a base tune from scratch. We elected option number two, and loaded a base tune that was close to the Olds’ parameters. You really should know your camshaft profile, etc. before proceeding here.
To tweak one of the base tunes follow Holley’s section 3.3.2, “Creating an Initial Calibration” in the Step-By-Step Beginners Tuning Guide (found in the Help menu).The process for building a base tune from scratch is explained in section 2.2.2, “Creating an Initial Calibration” in the Experienced User Tuning Manual (also found in the Help menu).
Holley has included a number of base calibrations that can be loaded into the ECU so why not take advantage of that? We did. You can find a complete listing of the included base calibrations in the Help menu (Help >Contents>Base Calibration Information). Each has a brief description, and they are separated into TBI and MPFI base calibrations.
After looking a few of them over, we settled on the 496_650HP base calibration for the Olds, found in the Custom Calibrations section. Because we’re using E85 fuel and not a DIS ignition system, we need to change those things in the base calibration. This is easy: We simply followed section 4.0 in the in the Step-By-Step Beginners Tuning Guide, “Step-By-Step INITIAL STARTUP INSTRUCTIONS.”
The Holley software stores tunes in Global Folders. A Global Folder has the following discrete files at a minimum:
- FuelFile(.fuel) • Idle File (.idle)
- Sensor File (.sensor)
- System File (.system)
Our tune also has a Nitrous File (.nitrous); we add that after we get the Olds running the way we want it to naturally aspirated. Each of these files is created (or tweaked) by the user in the software by choosing the appropriate icon in the title bar.
Although the software has a seemingly endless array of adjustments, the objective here is to get the vehicle running (we fine-tune it in Chapter 7). Build the tune on the laptop that will be used with the vehicle.
At this point, the laptop is not plugged into the ECU. The objective here is to get you comfortable with the software, navigating it, etc. so have fun!
The following 10 steps apply to the V2 software.
Launch the Holley EFI software from the icon on your desktop.
Choose Open Global Folder.
Double-click on the Custom Calibrations (Cals) folder.
Double-click on the 496650 HP Global Folder. To prevent making changes to this tune, make a copy of this global folder, which is specific to your application, before proceeding. (To do that, click on File > Save Global Folder As and choose your folder name. Type an appropriate name for your tune, and click Save. Save your tune in the Custom Cals folder to make it easy to find later.)
From the Toolbox menu, select Preferences. Check Display Pressure as PSIA if you’d like to see MAP readings in PSI versus kPa. If you are using an HP EFI ECU, you also select that here.
Click on the System ICF icon on the taskbar (looks like an ECU). This brings up the SYSTEM PARAMETERS box in the left column.
Let’s begin with Engine Parameters. We need to make the following changes for this installation:
- Change Engine Displacement to 462ci
- Change Fuel Type to E85
- ChangeWidebandOxygenSensor to Bosch
- ChangeNumberofSensorsto2; this brings up a Sensor Averaging window, and for now we select Average
- In the FUEL SYSTEM box, change System Type to 83LB Holley 522-838; this automatically triggers the low-impedance setting in the Injector Type selection in the INJECTOR SET 1 box
Click on Ignition Parameters in the SYSTEM PARAMETERS box on the left.
We need to make the following changes for this installation:
- Change Ignition Type to Custom, which brings up the CRANK SENSOR window
- SensorTypedefaultshouldbe DIGITAL FALLING; if not, select it
- SetTDCToothNumberto11, which is how Bill set it up when he installed the crank sensor
- Change CAM SENSOR type to Not Used
- Change OUTPUT SETUP type to Points Output, which allows the ECU to trigger the MSD Digital 6ALbox
- Click again on Ignition Parameters on the left
- Set CRANKING PARAMETERS timingto12.0degrees
- Set the MAIN OVER-REV REV LIMITER as you see in Figure 6.56
Click on Closed Loop/Learn in the SYSTEM PARAMETERS box on the left. Then:
- Select Enable Closed Loop
- ClickontheLearnParameters box at the top
- SelectBaseFuelLearnEnabled (for now, leave the Base Fuel LearnGainat100percent)
- Click Save and close the SYSTEMPARAMETERSbox before proceeding
Click on Sensors ICF Icon
We used a 1-bar MAP sensor in this installation, which is the default. All of the other sensors in the software are also set to default to the Holley sensors we used in the installation. It’s never a bad idea to verify this, though.
- Close the SENSORS box before proceeding
Click on the Fuel ICF Icon.
Table(fromgasolinetoouruseof E85) as follows:
14.7:1 (1 Lambda) is stoichiometric for gasoline
9.8:1 (1 Lambda) is stoichiometric forE85
1 Lambda = 14.7:1
X A/F ratio/14.7 = Lambda
Lambda x 9.8 = correct E85 value
For example, consider a cell with 13.6:
13.6/14.7 = .925 Lambda
.925 Lambda x 9.8 = 9.06
This measurement represents the conversion of the gas value to value for E85.
Each of the cells in the table has a resolution to one-tenth. Round up to the nearest tenth to make the mixture leaner; round down to make it richer.
Changing the values in the Target Air/Fuel Ratio Table is easy; click and drag all of the cells with the same value, type in the value you desire, and press Enter. All cells are updated accordingly.
Bill converted all values that were listed at 14.0 to 9.8 to achieve 1 lambda with E85 in the all-important idle and cruise (drivability) areas, which is what he previously determined works best for his combination in the Phoenix climate when it was carbureted.
After the conversion, the Target Air/Fuel Ratio Table looked like the one in Figure 6.60.
Remember, we just need to get a base tune in the ECU so we can start the engine. Additional tuning may alter these values. There are many additional FUEL SETTINGS, but for now, we can leave them as is from the tune we’re tweaking.
- Close theFUEL box before proceeding
Click on the Idle ICF icon.
- ClickontheIdleSpeedtabatthe top.(Idlespeedispre-setat1,000 rpm. We tweaked this a bit for whentheenginewarmsup.You can either enter the values in the white boxes at the top and press enter, or click and drag the yellow boxes to the desired values.) (SeeFigure6.61.)
Click on the Spark ICF icon.
Pull out the notes that you took earlier regarding the timing your vehicle had before you removed the carburetor.
Pull out the notes that you took earlier regarding the timing your vehicle had before you removed the carburetor.
- Click on Base Timing Table
- Modifythetableaccordingto your combination (in the case ofBill’scar,wesetallcellsto31 degrees, which is exactly how his timing was set up before we began the conversion. Later, we add some timing in the idle and drivability areas to improve the burn of the mixture, improve fuel economy, lower exhaust temperatures,etc.)(SeeFigure 6.62.)
- Click Save
3. Load Base Tune into ECU
Now that the base tune has been tweaked, we can load it into the ECU. Fortunately, that’s simple. Before proceeding, it’s time to install the fuses for the ECU. Also, ensure that the fuse to the fuel pump is still removed so that it’s inactive during the following steps.
Plug the USB cable into the port of the laptop that you set up to work with the ECU when you installed the USB bridge at the end of Stage Three (see page 116).
Open the Holley software and choose OPEN GLOBAL FOLDER.
Find your tune in the Custom Cals folder and click Open.
Turn the ignition power on, ensuring the USB cable is connected.
The Communication mode is just to the right of the Toolbox on the Menu bar. It should now say USB Link.
Click on the USB Link button; this starts a sync between the Global Folder you currently have open and the ECU.
Because the ECU has no Global Folder in it currently, select Send to ECU. The Communication mode shows Online while you are communicating with the ECU or looking at the settings within the Global Folder stored within the ECU.
Now that the Global Folder has been sent to the ECU, I recommend that you surf through all of the settings you’ve made (while online) to be sure that everything is accurate. Pay close attention to the oxygen sensor settings in the SYSTEM PARAMETERS to be sure that you have set it correctly.
While online, you’ll notice that several of the parameters of the Global Folder can be manipulated in real time (even when the engine is running), while others can only be manipulated when you are not online (shown as grayed out). If you have to make any changes to any grayed-out parameters within the Global Folder in the ECU, simply switch the ignition off, make the change, switch the ignition back on, click on the USB Link button, allow it to sync, and then follow the instructions to send your changes to the ECU.
Finally, switch the ignition off and then back on to cement the change. Incidentally, the process of turning the ignition key off and then back on is referred to as cycling the key.
4. Perform Calibrations Before Engine Start
This is the final step before starting the engine. Each of the following steps is critical to ensure a successful start-up.
Ensure all components are properly installed and wired. Compare your work to the diagrams to ensure accuracy.
We manually rolled over the engine in Bill’s car to ensure that we had the rotor pointing at cylinder number-1 with the timing on the balancer at 31 degrees BTDC to ensure a quick start. This was off by 180 degrees so we rotated the engine one full time.
Before proceeding, install any fuses for any ignition components.
Throttle-Body Idle Settings
The throttle blades need to be open enough to allow the engine to idle. Adjust the idle setting for the throttle blades on the throttle body to achieve this. If the throttle blades are open too far, it simply causes a fast idle, which is easily corrected after the engine is started.
Verify Sensor Functionality
After you’re happy with the tune in the ECU, switch the ignition off and plug in the oxygen sensors. Turn the ignition key back on, click on the USB Link, and allow it to synch.
After the synch, look at the Data Monitor box in the lower left. The first view is Sensors and you should have readings for TPS (move the throttle to be sure that it changes), MAP, MAT, CTS, battery, oil pressure, fuel pressure, and IAC position.
Click on the right arrow at the top of the box to scroll to the next window (Fuel Tuning) and verify readings for the oxygen sensors. If you do not have readings for all sensors, remedy it before proceeding.
The Step-By-Step Beginners Tuning Guide has a place for you to document each of the sensor readings if you choose to do so.
Perform a TPS Autoset
You must perform this or the ECU does not allow the engine to start. The purpose is to calibrate the TPS to the ECU based on your linkage setup, etc. With the ECU online, click on the down arrow next to the SyncwithECUicon(the twoarrows in the shape of a circle) on the menu barand select TPS Autoset(or simply press Ctrl + T). Follow the directions on the screen.
Check Cranking Timing
Unplug the fuel injector harness. (Obviously,the engine will not start with the fuel injector harness unplugged and the fuse for the fuel pump removed.) Connect a timing light and verify the timing while a helper cranks the engine.
Keep in mind that you may need to crank the engine for a while to get the timing light to flash even once, so ensure your battery is fully charged. The timing you read on the balancer should be close to the value you have set in the SYSTEM PARAMETERS > Ignition Parameters > Cranking Parameters > Timing in the Global Folder. If this is off by a little bit with a crank trigger(as in this installation), it can be adjusted in the software after fire-up so don’t sweat it. If this is off by a lot, you should verify the proper installation of the pickup of the crank trigger sensor.
When you’re happy with the value, plug the fuel injector harness back together.
Check Engine Cooling
At this point, we’ve not connected the ECU to the electric cooling fans in Bill’s Olds. For now, they are activated as before, manually. Consider this before attempting to start your vehicle.
5. Start Engine
If you made any changes to the settings in the Global Folder between the last time you performed a sync and now, you must cycle the ignition key(turnitoffandthenbackto the IGN/RUN position) and perform another sync.
You’re now ready to start the engine. Ensure that your software is up and the ECU plugged in before proceeding.
- Withtheignitionoff,reinstall the fuse for the fuel pump
- Turntheignitionon,andallow the ECU to prime the fuel system
- Withouttouchingthethrottle, start the engine; it should immediately start(Bill’sdid)
If the engine does not start, refer to the “Basic Tuning” section (Chapter 5.1) in the Step-By-Step Beginners Tuning Guide before proceeding.
Assuming the engine does start, press the USB Link button to establish communication between the ECU and laptop so that you can utilize the Data Monitor in the lower left.
Press the right arrow to scroll to Idle Tuning.
Verify that the fuel mixture isn’t excessively rich, which could damage the engine or catalytic converters. If the engine is running excessively rich, turn it off and refer to the “Basic Tuning Section” (Chapter 6.1A) of the Step-By-Step Beginners Tuning Guide before proceeding
If the engine runs smoothly and isn’t excessively rich, allow the coolant temperature to climb until the ECU switches to closed loop.
Press the right arrow in the Data Monitor to scroll to Fuel Tuning so you can monitor whether the system is operating in open loop or closed loop. Once the system is in closed loop, the ECU begins adding/ subtracting fuel to achieve the target air/fuel ratio. At this point, you can watch the following happen live:
- Click on the Target A/F Ratio (noticethedotswirlingabout)
- Click on the Learn Table (the ECUplots+/- changes to the Base Fuel Table to achieve the TargetAir/FuelRatio)
6. Final Calibrations and Test Drive
Before taking the Olds for a victory lap, we have two final calibrations to make: ignition timing and idle calibration. We do the ignition timing first, because changes to the timing can affect the idle.
We use a crankshaft trigger in this installation so turning the distributor by hand does nothing to affect timing. Rather, all timing changes are made in the ECU via the software. We need to ensure the reading on the balancer matches the reading in the ECU so that the values in the Base Timing Table are absolutely accurate. Have a helper connect a timing light and be ready to observe the timing reading on the balancer. Then:
- Start the engine and allow it to idle
- With the ECU online, scroll to Idle Tuning in the Data Monitor and note the Ignition Timing reading
If the timing on the balancer is not identical to the timing shown in the Data Monitor, it is easily adjusted in the software. To do so, note the difference (e.g., 34 on the balancer and 30 in the Data Monitor; the difference is4degrees).Now,shutthe engine off and move the ignition switch to the off position. The ECU is now offline.
- Click on the System ICF icon > SYSTEM PARAMETERS > Ignition Parameters > IGNITION TYPE > Configure
- Adjust the Timing Offset up or down by the difference that you’ve noted
- Turn the ignition switch to the IGN/RUN position, click the USB Link button and allow the ECU to sync
As the tune on the laptop has been changed, it does not match the tune in the ECU so follow the on-screen instructions to update it. After you’ve sent the changes to the ECU, cycle the ignition key and then start the vehicle.
With the ECU online, compare the timing reading on the balancer to the timing reading in the Data Monitor again to be sure that it’s correct. Bill and I took a few times to get this perfect. We had to drive the vehicle for a bit first before we could verify this at different RPMs as the ECU is mapping the Fuel Tables according to the Target Air/Fuel Ratio Map. Therefore,aconstant RPM (say, 3,000) is not achievable until this has been done.
But it is good enough for a test drive.
Allow the engine to reach normal operating temperature. Then the idle can be evaluated. If the engine idles higher than the Idle Speed setting (IdleICF)you set in the Global Folder, you need to adjust the throttle blades manually to reduce it. Anytime you make a mechanical modification to the throttle linkage or throttle blades, you need to perform another TPS Autoset so that the ECU and throttle are properly calibrated. Once you’re happy with the idle, these final calibrations are done.
By now the vehicle should be idling smoothly and the ECU should be busy mapping the Learn Table according to the Target A/F Ratio Table. Ready to go for a ride? I thought you might be. First, it’s a good idea to give every line and fitting in the fuel system a second check for leaks. We had one very minor leak at the input of the fuel rails and actually had to remove the line and clean the mating surfaces with Scotch Brite to solve it.
The Victory Lap
Bill drove the Olds for 30 minutes or so while I sat in the passenger seat with the laptop and LM-2.It’s always a good idea to have a buddy go along for the test drive to monitor the live data available as the ECU maps the Learn Table while you keep your eyes on the road.
I monitored the mapping of the Learn Table, the actual A/F ratio as compared to the target A/F ratio(CL Comp in the Idle Tuning of the Data Monitor), TPS percentage, fuel pressure, oil pressure, etc. In addition, I had the LM-2 set to display Lambda so Bill could see at a glance how close to perfect the A/F ratio really was while he cruised around (1.0 Lambda is stoichiometric for E-85at9.8:1).
Bill was beside himself. He was immediately impressed by how dead-on the A/F ratio data in the Data Monitor was, compared to his trusty LM-2. “Dude, they’re spot on.” He was also amazed that he was able to cruise at 1 Lambda nearly immediately (the ECU mapping is incredibly fast) and this was maintained throughout all of the drivability area. “I was never able to achieve this kind of drivability with the carburetor. Never!” The LM-2 confirmed this.
Okay, I’m more than a bit familiar with the Holley EFI products as I’ve had an HP EFI system on my own vehicle for more than two years now and it works excellent. That doesn’t mean I can’t be impressed. I’m blown away by the engineering it took to allow us to achieve our goals so quickly with Bill’s Olds. It’s such a versatile system and we’ve barely scratched the surface on its capabilities.
As an author, I do my best to remain neutral and unbiased. As an enthusiast, this sometimes proves to be difficult. The Holley Dominator system is easily one of the coolest aftermarket products I have touched.
Bill and I smiled for the rest of the day.
Written by Tony Candela and Posted with Permission of CarTechBooks