We're going to give you three words that strike fear into the hearts of many hot rodders, even more so than "wiring" or "upholstery." Electronic fuel injection. There, we said it! But the simple fact of the matter is, EFI shouldn't scare anyone. Or at least it shouldn't anymore. Images of tuning using laptop computers and miles of wiring leading to any number of mysterious black boxes can be dispelled nowadays. Of course, you can still have that if you wish, but you can also have "fit and forget" EFI too.
To prove our point, we followed along at Kiwi Steve's Hot Rod Shop as the guys were installing throttle body injection (TBI) on Jules Engoren's '34 phaeton. Jules has owned the tub forever; in fact it was his first real car, and he drives it everywhere. A few years back he installed a crate ZZ4 engine, but noticed a lack of power at high altitudes, such as in Colorado, and not-so-great fuel economy at speeds above 70 mph. Yes, this is one well-traveled and hard-driven hot rod, and Jules wanted it to remain that way. Discussions with Kiwi Steve led to the decision to replace the Edelbrock carburetor with fuel injection, but on a budget. Which is why the throttle body itself and the distributor are OEM GM swap meet finds. The throttle body is what you'd find on an '88-95 Suburban or truck with a 350ci engine. The adaptor plate and even the wiring harness, though brand-new, were sourced on everyone's favorite Internet auction site.
Here's our subject vehicle,...
Here's our subject vehicle, Jules Engoren's much-traveled and road-worn '34 phaeton. Throughout the following pictures bear in mind this is an older, homebuilt hot rod and not some pristine show car!
That harness was produced by Howell Engine Developments, which is also where the ECM was sourced from. In fact all the components used here are available from Howell, and indeed they can supply a Universal V-8 Throttle Body kit, but where OEM parts from a parts house or good used parts could be used for this particular job, they were. The ECM is the computer that mounts inside the car. Howell uses GM ECMs, which are commonly found in pickups and vans from 1987-95. They are tested and carry a guarantee, and the Howell Throttle Body Injection wiring harness is designed to work with these ECMs. Howell also offers custom-calibrated, application-specific PROMs, the "chip," if you will, that sets the parameters for engine and transmission (if electronically controlled) calibration. It would be easy to get lost in the differences between ECMs and PCMs and PROMs and MEM-CALS here, so we'll simply say do some research for your application, such as year of engine and transmission, or leave it to the experts such as the guys at Howell, who will be able to hook you up. Meanwhile, we'll concentrate on the application in our guinea pig phaeton.
Before we start, we should mention that it's a good idea to trial-fit everything before modifying anything, check for clearance for the new fuel supply and return lines (yes, you'll need to add a return line for injected motors) against the intake manifold, adaptor, or distributor, and check for clearance between the hood or radiator braces and the throttle body. We should also mention that one thing we haven't shown here is the speed sensor, an electronic pulse generator that mounts in the speedometer drive to tell the ECM when the car is at rest or at what speed it's traveling.
EZ EFI
We couldn't run an article on easy-to-install throttle body fuel injection without mentioning this new system from FAST. The EZ-EFI system is a self-tuning injection system that can support up to 550hp and is supplied complete with the ECU, oxygen sensor, wiring harness, and optional fuel pump.
The business end of the package is the 4150 throttle body which can be bolted to any existing 4150-type inlet manifold and includes appropriate injectors and fuel rails. The original throttle linkage can be used and it accepts all OEM sensors. FAST claims the system can be installed in less than a day and doesn't require any EFI experience or expertise. Once the hardware is installed, a few Setup Wizard questions have to be answered on the included handheld display and the system tunes itself while the car is driven.
 The crate ZZ4 features a large...  The crate ZZ4 features a large cap distributor, mechanical fuel pump, and Edelbrock carburetor. The ZZ4 is an ideal engine to convert to GM fuel injection, as the intake manifold is the old Quadrajet mounting pattern, the same as the throttle body adapter. |  Apart from the throttle body,...  Apart from the throttle body, TBI adaptor, and the distributor, everything here--ECM, fuel pump, fuel filter, PROM, oxygen sensor, knock sensor, MAP (manifold absolute pressure) sensor, and ESC (electronic spark control) module--is available from Howell, as well as the service manual, either individually or as a universal V-8 TBI kit, complete with throttle body. The distributor is a small cap late-'80s GM HEI, required as it's computerized and the existing one wasn't. |  The wiring harness is also...  The wiring harness is also from Howell and is perfect for transplanting TBI or TBI-equipped engines into precomputer-controlled vehicles. A new harness is paramount on installations such as this, as incorrect wiring will ruin the system, and of course it eliminates any mistakes that can occur when splicing into an existing harness. |
 The ECM is a GM part that...  The ECM is a GM part that Howell tests and offers with a guarantee. That's the correct PROM for our application about to be installed in the ECM. |  The throttle body used on...  The throttle body used on the phaeton is on the left, with a pair of new -6AN to metric GM fittings from Pure Choice Motorsports installed in the fuel inlet and return ports. Antiseize was used on the threads before installation. The throttle body on the right is from a big-block with larger butterflies and was used in a Mercruiser application. |  The original plan was to use...  The original plan was to use this GM 454 truck manifold adaptor between the throttle body and the manifold, as it has vacuum ports and a water jacket that enables the manifold to be heated for driving in colder climates (the ZZ4 doesn't have an exhaust crossover to heat the inlet). |
 Time and budget limitations...  Time and budget limitations meant keeping the stock throttle cable bracket, which didn't align with the throttle body when mounted to the 454 adaptor, so this simple aluminum plate adaptor was sourced on the Internet and used instead. Of course, this would be simple to fabricate yourself. |  Between the water temperature...  Between the water temperature gauge sender and the thermostat housing on the ZZ4 intake manifold, there's a boss that accepts a new GM water temperature sender for the ECM. |  As the ZZ4 is a stock engine,...  As the ZZ4 is a stock engine, a stock GM knock sensor could be used, though be aware these are engine-specific. The sensor controls timing by sensing any pre-ignition conditions. Instead of fitting it into the drain plug hole in the block where it can easily be added, this hole on the left rear of the block was retapped, as the headers blocked usage of the drain plug hole. |
 The only welding involved...  The only welding involved in this project was to add a threaded bung in the right exhaust to accept an oxygen sensor. This is a single wire sensor, though three wire heated versions are available for mounting further back in the exhaust system. The tight-tuck shorty headers on the phaeton meant the sensor could be mounted near the exhaust ports where the gases are hotter. |  The harness was test-fitted...  The harness was test-fitted early in the installation, as the length of the wires dictates where components such as the MAP sensor and coil will be mounted as they're not on stock brackets. A hole was drilled in the lower right side of the firewall for the harness to pass through and hook up to the ECM mounted under the dash. |  The coil is a stock GM item...  The coil is a stock GM item for a small HEI distributor application. It would normally mount on the intake manifold, but not having the stock bracketry, a simple bracket was fabricated to mount it to the firewall. |
 This ring spacer performs...  This ring spacer performs two functions. It acts like a velocity stack and smooths airflow into the throttle body, and is necessary in order to fit a "normal" air cleaner. These spacers are found on OEM applications. |  In order to bolt on that air...  In order to bolt on that air cleaner, a piece of all-thread was bent and centralized on the throttle body. With it installed, the motor will still look like a regular carbureted engine at first glance. |  This ring spacer performs...  This ring spacer performs two functions. It acts like a velocity stack and smooths airflow into the throttle body, and is necessary in order to fit a "normal" air cleaner. These spacers are found on OEM applications. |
 The ECM was mounted under...  The ECM was mounted under the dash on the right-hand side amid the existing wiring. |  There are two things to note...  There are two things to note here. Firstly, the MAP sensor is mounted on the throttle body using a ring bracket from a Mercruiser marine application. The sensor measures manifold vacuum and senses barometric and altitude changes, allowing the ECM to supply the required correct fuel and spark settings. Secondly, this shows the braided fuel lines that were custom-made at NAPA with AN fittings to match the Pure Choice adaptors, along with elbows at the end for distributor clearance. |  The lower end of the braided...  The lower end of the braided fuel hoses were ordered with inverted flares to connect to the hard lines on the chassis. The upper hard line is the existing line, while the lower is a return line which was fabricated and runs back to the gas tank. |
 The fuel filter was mounted...  The fuel filter was mounted in the fuel supply line on the inner chassis 'rail. Note the new return line below it. |  A high-pressure fuel pump...  A high-pressure fuel pump is required for a TBI fuel system, delivering 18-20 psi. Stock vehicles have a pump inside the fuel tank, but Howell offers this inline electric pump, mounted here just forward of the tank, adequate for systems up to 350hp. |  The finished installation,...  The finished installation, which apart from some extra wiring and new braided fuel lines, looks very much like it did when we started! Running fuel injection doesn't mean you have to have a large aluminum or plastic "box" atop your motor. Though Jules has yet to make any high-altitude trips, he reports increased throttle response around town with the TBI. |