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How to Install the Fast EZ-EFI Unit - EFI Evolution

We ditch our archaic '80s-era throttle body injection for a more capable EFI system that'll make the most of our engine.

Patrick Hill Feb 5, 2014
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Ok. Let's start by stating the obvious … fuel injection has a come a long way since the '80s. You know it, we know it, and anyone with a car built in the last 10 years knows it. So, we'll skip the history lesson and rehash of what everyone knows already when it comes to EFI.

Here we have our '92 Camaro RS. A factory 305/automatic car, we picked it up for $800. No rust, never been in an accident, 205k miles on the odometer, and in overall good shape other than a worn out interior and non-functional power windows. But in the world of third gens, unless you've got manual windows, at some time or another yours stopped working too.

The factory L03 engine was rated at 170 HP, not bad for the time when it came to a base V-8, and healthy on the torque side. The L03 was the optional engine for the RS model (TPI engines could only be had with the Z28) and came equipped with a throttle body injection unit controlled by GM's Histrionics computer system. For its day the system got the job done, and since most TBI engines were left alone mod wise, they were more than adequate. Today there are still millions of them out there doing the job of mixing fuel and air for the engines in various GM cars and trucks.

But for anyone looking for performance, this system just isn't up to the task. After we installed a new Chevrolet Perofrmance Fast Burn 385 crate engine in place of the tired 305, we left the old TBI system in place to see how it would respond. While the car ran fine, we could tell the TBI unit was choking the engine for power, and the dinosaur EFI system did not really give us anywhere to go for trying to tune it. Years ago there were plenty of companies burning performance chips for older GM computers, but today most of them are gone.

Looking for the best solution that would make future mods easy, we decided on FAST's EZ-EFI self-adaptive fuel system. Using a high-pressure, fuel injector-equipped four-barrel throttle body, EZ-EFI is FAST's user friendly system that requires no laptop tuning, no complicated tuning software, and can be installed on almost any engine as long as the intake will accept the throttle body. It features an adaptive learning system that, once a set of base parameters are set (engine size, number of cylinders, etc.) will handle adjusting the various parameters until it finds the optimal settings for everything. All you have to do is drive the car around while the computer does the work. It's that simple.

Follow along and we'll show you…


1. The starting point for our install is FAST's (Fuel Air Spark Technology) EZ-EFI unit. This system is one of the easiest ways to either convert from a carb to EFI, or switch from a limited factory EFI system (like in our case) to a modern one with programmability, and better adaptability to performance mods. The system uses a throttle body equipped with fuel injectors and sensors, with a Holley base flange. This gives the EZ-EFI system an almost universal application, as long as your intake can accept a standard Holley flange.


2. The EZ-EFI kit includes a fully labeled wiring harness, tach driver, O2 sensor, fuel pump, and the various parts and pieces needed to install the system.


3. The first step is clearing away all the factory TBI junk, then pulling the manifold. The old TBI system was fine (though not spectacular) for running the stock 305, but with our Chevrolet Performance crate engine, it just can't keep up. Plus, there's virtually no tunability with the factory system, leaving us nowhere to go if we add any other engine mods.


4. We'll end up reusing the factory fuel lines coming from the tank, so after disconnecting them from the engine lines we covered them up and secured them out of the way.


5. Next to go is our factory distributor. The EZ-EFI system doesn't control timing or spark advance, and uses a standard HEI-style distributor and coil.


6. Replacing our TBI intake is this Holley Street Dominator unit, part no. 300-64. It's for '87-up small-blocks, and uses the later model A/C and alternator mounting provisions, along with having a port for EGR, and all the runner vacuum taps needed.


7. For ignition we went with a Performance Distributors billet, small cap HEI unit with vacuum advance and remote coil. It has a simple, three-wire hook up that'll interface with our EZ-EFI system for power, and provide plenty of spark energy to let our small-block make the most of the new fuel system.


8. The FAST throttle body is pretty much self contained, with all the EFI sensors and fuel injectors already bolted on. It simply drops onto the intake and gets bolted down. If you're running a carb equipped engine that already has four-barrel linkages, you won't even have to change those to work with the FAST throttle body.


9. Once the intake was secured with new gaskets, we installed the included coolant temp sensor, along with our other coolant fittings, plugs, and vacuum hookups.


10. The FAST throttle body can be set up to have the fuel line connection for the fuel rails on either side. We had to switch ours because the connection interfered with the throttle linkage.


11. The control harness for the EZ-EFI system comes fully labeled, so you know instantly where all the connections go with no mystery. While not fully plug-and-play, EZ-EFI has most of the work already done for you, with only some simple wiring mods on the car's factory harness necessary. If you're running an earlier, non-computer controlled vehicle, a lot of this you won't have to deal with.


12. We decided to mount the ECM for the system to this bracket on the driver's side, outboard of the power brake booster. This keeps the ECM in a safe place shielded from rain, debris, and just about anything else that could harm it.


13. This tach/RPM module has to be installed so the ECM gets RPM data, and the factory tach also still gets a signal. Per the instructions and the labeled harnesses, it hooks into the EZ-EFI harness and the new coil.


14. So our factory tach will still work, we hooked the factory tach wire (pink one that originally went to the factory coil) into our new harness, in conjunction with our new EZ-EFI wiring. When we started the car up, the tach and the EZ-EFI controller showed identical rpm.


15. Per the Performance Distributors and FAST instructions, everything is wired into the positive and negative terminals on the new coil.


16. With that done, next up was plumbing the fuel system. First the lines for the throttle body were hooked in.


17. One advantage we had with our '92 Camaro were its existing high-pressure fuel lines, which meant we didn't have to plumb anything from the tank to the engine compartment. To hook the FAST engine compartment lines in, we took our old engine compartment lines to our local hose/fitting shop, and had the ends that hooked into the factory fuel lines modified to have AN male fittings so we could attach the FAST lines. This cost us about $30, and made the hookup super easy.


18. First thing to install is this inline filter on the fuel line feeding the throttle body. We also left our factory fuel filter (back by the tank) in place for extra filtration.


19. Next was the fuel pressure regulator, installed in the return line. We mounted it on the fenderwell so it would stay secure, and far enough away from engine heat not to vapor lock. The regulator comes pre-set for the correct fuel pressure for the FAST throttle body.


20. Next up is wiring our fuel pump. This green wire from the EZ-EFI harness must be connected to the factory fuel pump relay.


21. This is the factory pump relay on our Camaro. We used a factory wiring diagram to locate it.


22. After opening up the factory harness going into the relay, we cut the corresponding green factory wire, then spliced in the EZ-EFI wire so it went through the relay.


23. From there we ran the harness wiring for the fuel pump all the way back to the tank.


24. After we unplugged the factory sending unit from the main harness, we dropped the tank down.


25. With the tank down we could remove the fuel pump assembly to install our new pump.


26. Quick tip for third-gen Camaro owners out there to make tank removal/install much easier. With the tank down, use a hammer and beat/fold this lip of sheetmetal (left from factory assembly) down till it's flush with the frame rail, as in the photo. This lip always catches the filler neck, making it impossible to angle the tank downwards enough to remove it without having to disconnect the rear suspension and lower the rear end for clearance.


27. Even though our RS came with fuel injection from the factory, it was the lower pressure TBI system (pump on the right). Our FAST throttle body requires higher pressure, similar to the factory tune port system. While the FAST kit comes with a high pressure fuel pump (pump on the left), it requires decent modification of the factory sending unit/fuel pump assembly for installation. The easy solution is to go with the factory pump for a TPI equipped Z28 (pump in the center). This pump bolts right into the factory pump assembly with no mods, and supplies enough pressure to run the injectors on the new throttle body. Added bonus is this pump's readily available at any local auto parts store.


28. After installing the new pump, the next step was wiring in the fuel pump controller for the EZ-EFI system. First, the gray wire on the factory fuel pump harness is cut, then the red wire from the EZ-EFI harness we ran to the back is spliced into the gray wire going into the tank. Now the new EFI system will control the power supply to the pump. The rest of the factory harness stays in place, as it still handles the signal for the fuel gauge in the dash.


29. With the fuel system finished, we installed the included O2 sensor in the factory exhaust location, then plugged it into the EZ-EFI harness.


30. Along with the new distributor and coil, we also installed a set of Performance Distributors' LiveWires plug wires. They come pre cut to length, terminated, and have heat resistant fiberglass sleeving to keep them from getting melted near hot exhaust manifolds and the like.


31. The ECM has to be hooked directly to the battery for constant power so the computer doesn't reset when the key is off. To keep things neat, we ran the main power wire from the ECM under the factory radiator shroud, across to the battery.


32. Pretty straightforward, the power wire hooks directly to the positive battery terminal.


33. Because our Camaro had a two-barrel TBI unit, the factory throttle cable and transmission TV cable wouldn't work on the new FAST throttle body (too short). Another easy solution, we called Lokar, and got their Hi-Tech Throttle Cable (part no. TC-1000HT), throttle cable bracket and springs (part no. SRK-4000), and 700-R4 kickdown kit (part no. KD-2700HT).


34. Before installing the new TV cable, this retaining collar must be installed, along with the O-rings on the end of the tube so fluid doesn't leak out.


35. When installing the TV cable, you have to first install this end into the hook lever in the hole. Word of advice here: Installing the TV cable on a third-gen is usually easier if you lower the trans some. Once the nub is locked in place, then the cable housing is pressed in, and the bolt on the retaining collar tightened. Then the other end of the cable is fed up to the throttle body.


36. To install the throttle cable, the collar on the engine end must be removed, so the cable can be taken out.


37. This retaining collar must be removed from the factory throttle cable (on the pedal end) and installed on the new throttle cable.


38. Once it's secure, then it's hooked to the factory gas pedal like so. Then the cable is run through the factory hole in the firewall. We used a pair of big washers to help cover the hole on the firewall when we tightened everything up, as the diameter of the Lokar cable is much smaller than the factory one.


39. After measuring and trimming down the cable to fit our throttle body, each end was collared, then the appropriate connector attached. The bottom cable is the transmission TV cable, the upper the gas pedal cable. Once attached, we got in the car and made sure we had full pedal travel, and that it returned to the no throttle position with no issues.


40. The Lokar cable bracket attaches on the left rear side of the throttle body, instead of on the intake manifold bolts like the factory cable bracket. It also came with the necessary return springs, as seen here attached.


41. Our old battery was toast. For a replacement, we contacted Optima for one of their rock solid, super dependable red top batteries. With 730 cold cranking amps, even on the coldest Florida days (laughing as we say this) it'll have no problems starting our small-block. Actually, heat is a bigger problem for batteries than cold, and Optimas are built to be reliable.


42. With power hooked up, we could plug in the EZ-EFI handheld programmer, and set the engine parameters in the computer. Just follow the steps on the screen, they're self explanatory and easy to understand.


43. With the ECM programmed with our engine's base parameters, we turned the key, and after a few cranks the 350 came to life. We checked the fuel lines for any leaks, and the gauge on the fuel pressure regulator to make sure we had plenty going to the injectors.


44. And there you have it. All that's left is to take the Camaro for a short spin so the EZ-EFI's adaptive learning computer can read all the data coming from the various sensors and “learn” what is the optimal air/fuel settings for our engine, along with all the other parameters. Don't be alarmed if your car doesn't run well at first, this is normal. It takes the EZ-EFI system a short period of driving time to make its settling in adjustments. You'll quickly notice the engine smoothing out and running better as the process takes place. When it's all done, you'll have a happily purring, EFI equipped engine. Watch for part two next month when we dyno test our Camaro, and play around with the EZ-EFI's custom settings to try and get more power.


Seffner, FL 33584
Holley EFI
Bowling Green, KY 42101
Memphis, TN 38118
Lokar Performance Products
Knoxville, TN 37932
Optima Batteries
Milwaukee, WI 53209



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