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DIY EFI
CONVERTING A VINTAGE BUICK NAILHEAD TO ELECTRONIC FUEL INJECTION IN A ONE-CAR GARAGE
HANDS ON
T E C H our humble author makes no claims of being a mechanic. But, if you need some sales-driving advertising done, I have nearly 25 years of experience in that field. I’m your man! But, every since I was smitten by a ‘55 Chevy Bel Air in the 8th grade, I’ve been a “car guy”. That’s why our “Company Car” is the mild-custom, unrestored “survivor” 1965 Buick Riviera (above). The Rivi is “motorvated” by the iconic 401cid Buick “Nailhead” engine. This particular powerplant was outfitted with the two-4bbl setup from a 425cid “Super Wildcat” 465 Nailhead. The previous (3rd) owner had outfitted the manifold with mismatched, aftermarket carburetors.Years of neglect and dormancy had caused those carbs to develop significant leaks. Fortunately, the previous owner also had a pair of the original 1965 Carter AFB carburetors (see inset above) on hand. After about three years and some dealing, I was the proud owner of the rare, correct-part-number AFBs. But the affair was short lived. The “rebuilt” factory Carters were as leaky as the old aftermarket carbs. Their crummy condition reared it’s gruesome head some 2000 miles from home. Shortly after installing the AFBs, we decided to tow the black and gray Buick from it’s Texas home to Reno/Tahoe for Hot August Nights ‘06. It was our tenth year attending the show and first year entering a vehicle. The lack of “shakedown” time after the induction transplant, precluded driving the car on the 4000-
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By D.J. Adams mile roundtrip trek. Tuning the car with the leaky carbs was a chore. But on the Friday night before the two-and-a half day roadtrip to Reno, we had it running decently, if not perfectly. But once off the trailer at a few thousand feet above sea level, the bad carbs had the Nailhead wheezing like my asthmatic uncle. I vowed to follow the latest diet trend and “cut the carbs”. The fuel-injection idea had been crashing around in my cranium for a couple of years. I had contacted a couple of the big induction-system companies and neither had anything for the Nailhead. Some other companies were developing multi-port fuel injection systems for Big Block Chevrolets. These systems had dedicated manifolds which are of a significantly different design than the Nailhead manifolds. We were then on the cusp of the burgeoning nostalgia rod trend and the Nailhead was beginning to experience a resurgence in popularity. Soon thereafter, I found a couple of companies that had multipoint EFI setups for the Nailhead. But they were all more costly than a hard-working ad man can afford. Then I discovered Affordable Fuel Injection. A web search led me to the Michigan-based company that specializes in custom-built EFI systems. AFI builds Multi-Port Fuel Injection (MPFI), Tuned-Port Injection (TPI) and Throttle Body Injection (TBI) systems. I like the novelty of the 2-carb setup on the big Buick. That’s why I chose to * Do-it-Yourself Electronic Fuel Injection
have AFI build a system with twin throttle bodies. Admirers often are surprised to see the two carburetors under the hood of what appears to be an upscale luxury cruiser. After imparting a little Nailhead history, I usually tell them about the engine’s hefty torque and how it is handy for getting the 4400-lb. car moving in a hurry. Although not considered a “musclecar” by most enthusiasts, the sporty ‘63-’65 Rivieras have no problem getting out of their own way. The standard 401cid “Wildcat 445” produced 325 HP and 445 lb.-ft. of torque. The mighty 425 cid “Super Wildcat 465” pumped out 360 HP (at 4,400 rpm) and a whopping 465 lb.ft. of torque (at 2,800 rpm). The advantages of EFI were clear: improved driveability, low maintenance, reliability, no cold starting and no problems with varying altitude. Affordable Fuel Injection’s high-quality systems live up to their name. The price for a custom-built EFI conversion kit was surprisingly reasonable. But I had questions for myself. I had to come up with answers, before I placed the order and AFI begin building my kit. Q: “Do I have the tools to do this?” A: “Yep. I have a good selection of hand, power, air and diagnostic tools.” Q: “Do I have the skill to properly install the system?” A: “Maybe not. But, it will be good experience. I’ll learn more about EFI and get a chance to hone my fabrication skills. It will also provide the motivation to re-route those heater hoses and clean up that unsightly mess of underhood wiring. The Rivi, nice as it is, isn’t a high-dollar show car. I don’t have to try to make it look like one. Chip Foose I ain’t. Besides, if I get in over my head, I can always get my street-rod building neighbor to help.” Q: “Do I have the time to do this?” A: I’ll just take my time and make it my “winter project”. The outdoor cruise season doesn’t kick off here in Texas, until about late March. It’s the 1st week of January. I should have it done by then. After sufficiently answering all my own questions, I called the tech guys at AFI and asked them dozens more. Satisfied with their answers, I gave them all the critical driveline specs. Again their systems are custom designed for your particular application. AFI’s techs use your info to program the system’s Electronic Control Module (ECM or computer), determine the configuration of all the required sensors and fabricate the wiring harness. Follow along as a weekend, shadetree wrench spinner brings a 42-year old ride into the age of Electronic Fuel Injection.
Affordable Fuel Injection’s TBI kits are quite complete and feature high-quality GM components. The custom kit for the Nailhead included two 4.3 throttle bodies, Electronic Control Module (ECM), dedicated wiring harness, fuses, relays, manifold adapter plates with gaskets, fuel pump with lifetime warranty, Oxygen (02) sensor and mounting boss, Manifold Absolute Pressure (MAP) sensor, Engine Coolant Temperature (ECT) sensor, fuel inlet/outlet adapters, checkengine light, Assembly Line Diagnostic Link (ALDL) connector and comprehensive instructions. Most AFI TBI kits include a distributor. But in anticipation of the updates, I had already installed a compatible MSD Billet distributor, MSD Blaster 2 coil and MSD 6A ignition. The system uses the 6A’s tach output to trigger the ECM.
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Saying the conversion was done in a one-car garage isn’t exactly accurate. It’s actually a 2-car garage with a 20x6’ shop attached. One bay has been occupied (for far longer than I like to admit) with our other project. The LS1-powered 1957 Chevy 2-door sedan served as a “temporary work bench”. So, for all practical purposes, let’s call it a one-car garage. Some of my car buddies scolded me for piling stuff on the ‘57, They reminded me how many hours and how much dough went into making the sheetmetal laser-straight and solid. I wouldn’t recommend doing this. Even with the cargo blanket, I will have to deal with some dings when it’s time for paint. But hey...a guy’s gotta’ do what he’s gotta’ do.
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D I Y E F I
Here’s where the ECM (computer) lives
I started under the hood. Here, the TBs are temporarily mounted on the adapter plates and intake manifold. Although the fuel inlet hoses are the high-heat-resistant fuel injection hoses, I might replace them with better-looking flex hose. I re-routed the heater hoses. They ran close enough to the throttle linkage to make me nervous. I used 3/8” and 5/16” barbed angle adapters to send the lines around from the heater core to the passenger side. Note the unsightly wires along the upper firewall. The EFI system wiring exacerbated this problem. I will clean them up later. Hey, don’t knock my bright blue, angled-boot plug wires. They allow a better view of those rare, finned-aluminum valve covers (which, admittedly could stand a good polishing).
I considered using one of the factory “idiot” lights for the system’s check-engine light. But decided to install the included light in a visible spot. The harness runs under the carpet below the AC evaporator.
It enters the engine compartment through a grommet in the passenger-side firewall.
The ALDL diagnostic port is mounted below the dash.I tested to make sure it clears the knees.
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D I Y The “dirty work” went on underneath. I envy those folks on those car-buildup, so-called “reality” TV shows. How easy it must be with their climate control, high-ceiling shops, vehicle lifts, free parts, large crews, sponsorship and big budgets. Try hours of lying alone on your back, on a cold garage floor, with dirt and rust constantly dropping in your eyes (the safety glasses kept fogging up) and a drop light that never seems to be facing the right direction. Now THAT’s reality! The 12-15psi electric fuel pump was installed at the floorboard. The in-line fuel filter is right ahead of the pump. I spliced both right into the existing 3/8” dia. fuel-feed line. I tried using the existing 1/4” dia. fuel return line. It was too small and caused the return-line pressure to be much higher than the required 2-3psi. I eventually bent a new 5/16” steel return line. The pressure was still a little too high, so I did the same with another 3/8” line. Problem solved! I made crude, but effective sheetmetal covers to protect the pump, filter and short length of rubber lines from road hazards. All my sheetmetal fabrication is done with a pneumatic cutoff tool, hand shears, a file, an anvil and a MIG welder. No fancy English wheels, metal brakes, plasma cutters, bead rollers or TIG welders. Although I was taught to use most of those tools by the late, legendary racer Buddy Morrison. I was a member of the Reher-Morrison Motorsports NASCAR Craftsman Truck team formed by Morrison in ’97-’98. Anyway...the factory 1/4” line ran into an orifice in the top of the fuel sending unit. I dropped the tank (after draining nearly 20 gallons of gasoline), capped the 1/4 inlet and fabricated a return inlet into the filler neck. I could have filled the tank with water and safely MIG-welded the 3/8” dia. steel nipple into the filler neck. But draining all the water from the baffled tank would have been a much bigger chore. A rubber grommet and Liquid Steel should do it.
“A rubber grommet and Liquid Steel should do it.” —D.J. Adams
Here are my low-buck, handmade road hazard protectors for the fuel pump and filter.
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Don’t fret. The rubber return line (top arrow above) goes behind and above the muffler with the tank in place. I wrapped it with high-temp. heat shield, just in case.
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Using the air cleaners from the old carbs took some adaptation. I added 1” spacers and notched the chrome tops for the injector-sensor wires. The filters are from K&N.
The Engine Coolant Temperature (ECT) sensor was threaded into a reducing bushing, where the original sensor entered the manifold’s crossover.
Here’s a closeup view of the sensor for the Idle Air Control (IAC) valve. There is one on the base of each throttle body.
The Throttle Position Sensor (TPS) connects at the base of the rear throttle body.
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The Oxygen (02) sensor is threaded into a weld-in boss in the passenger-side head pipe.
The Manifold Absolute Pressure (MAP) sensor is mounted on the firewall, towards the cowl.
“Do I have the skill to properly install the system?” —D.J. Adams The MSD 6A ignition box is on the driver’s side inner fender. The tachometer output (arrow) provides the trigger signal for the ECM.
I had to cut and drill the throttle levers in order to fabricate a custom linkage.
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D I Y E F I Here’s the finished underhood installation. As I mentioned, I might consider replacing the rubber fuel lines with shiny flex hose. The valve covers could use some polishing and the engine is begging for a new coat of paint. But I’m really looking forward to doing what the car was made to do: driving! At this point, I have had the car on jackstands for nearly three months. After all, it was a spare-time winter project. A mechanical whiz, staying after it, could possibly complete a similar conversion in a long weekend. There is a quarter-inch coating of dust on the shiny paint. The Autumn car-cruise season is upon us. Plus, local merchants tend to miss seeing me park the Buick at their establishments. I’m thinking that once we work out some little bugs (an open-loop 02 sensor code and slightly rich idle) and fine-tune it, it’s time to hit the road and enjoy the aforementioned benefits of Electronic Fuel Injection.
SOURCE GUIDE Affordable Fuel Injection 7575 N. Hollister Road Elsie, MI 48831 248-393-1621 www.affordable-fuel-injection.com
Questions? Thoughts? D.J. .Adams AdTex Advertising 817.244.5054 www.adtexadvertising.com
Next up: computer tuning and road testing. Finishing up.