TECH

HANDSON

CONVERTING A VINTAGE BUICKNAILHEAD TO ELECTRONIC FUEL

INJECTION IN A ONE-CAR GARAGE

DIY EFI*

Your humble author makes no claims of being amechanic. But, if you need some sales-driving

advertising done, I have nearly 25 years of experience inthat field. I’m your man! But, every since I was smittenby a ‘55 Chevy Bel Air in the 8th grade, I’ve been a “carguy”. 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 outfit-ted with the two-4bbl setup from a 425cid “SuperWildcat” 465 Nailhead. The previous (3rd) owner hadoutfitted the manifold with mismatched, aftermarket car-buretors.Years of neglect and dormancy had causedthose carbs to develop significant leaks. Fortunately, theprevious owner also had a pair of the original 1965Carter AFB carburetors (see inset above) on hand. Afterabout three years and some dealing, I was the proudowner of the rare, correct-part-number AFBs.

But the affair was short lived. The “rebuilt” factoryCarters were as leaky as the old aftermarket carbs. Theircrummy condition reared it’s gruesome head some 2000miles from home. Shortly after installing the AFBs, wedecided to tow the black and gray Buick from it’s Texashome to Reno/Tahoe for Hot August Nights ‘06. It wasour tenth year attending the show and first year enteringa vehicle. The lack of “shakedown” time after the induc-tion transplant, precluded driving the car on the 4000-

mile roundtrip trek. Tuning the car with the leaky carbswas a chore. But on the Friday night before the two-and-ahalf day roadtrip to Reno, we had it running decently, if notperfectly. But once off the trailer at a few thousand feetabove sea level, the bad carbs had the Nailhead wheezinglike my asthmatic uncle. I vowed to follow the latest diettrend and “cut the carbs”.

The fuel-injection idea had been crashing around inmy cranium for a couple of years. I had contacted a cou-ple of the big induction-system companies and neither hadanything for the Nailhead. Some other companies weredeveloping multi-port fuel injection systems for Big BlockChevrolets. These systems had dedicated manifolds whichare of a significantly different design than the Nailheadmanifolds. We were then on the cusp of the burgeoningnostalgia rod trend and the Nailhead was beginning toexperience a resurgence in popularity. Soon thereafter, Ifound a couple of companies that had multipoint EFIsetups for the Nailhead. But they were all more costly thana hard-working ad man can afford.

Then I discovered Affordable Fuel Injection. A websearch led me to the Michigan-based company that spe-cializes in custom-built EFI systems. AFI builds Multi-PortFuel Injection (MPFI), Tuned-Port Injection (TPI) andThrottle Body Injection (TBI) systems. I like the novelty ofthe 2-carb setup on the big Buick. That’s why I chose to

By D.J. Adams

* Do-it-Yourself Electronic Fuel Injection

have AFI build a system with twin throttle bodies. Admirers often are surprised to see the two carburetorsunder the hood of what appears to be an upscale luxury cruiser. After imparting a little Nailhead history, I usu-ally tell them about the engine’s hefty torque and how it is handy for getting the 4400-lb. car moving in ahurry. Although not considered a “musclecar” by most enthusiasts, the sporty ‘63-’65 Rivieras have no prob-lem getting out of their own way. The standard 401cid “Wildcat 445” produced 325 HP and 445 lb.-ft. oftorque. 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 andno problems with varying altitude. Affordable Fuel Injection’s high-quality systems live up to their name. Theprice for a custom-built EFI conversion kit was surprisingly reasonable. But I had questions for myself. I hadto 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 fabrica-

tion skills. It will also provide the motivation to re-route those heater hoses and clean up that unsightlymess of underhood wiring. The Rivi, nice as it is, isn’t a high-dollar show car. I don’t have to try to make itlook like one. Chip Foose I ain’t. Besides, if I get in over my head, I can always get my street-rod buildingneighbor 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 customdesigned for your particular application. AFI’s techs use your info to program the system’s Electronic ControlModule (ECM or computer), determine the configuration of all the required sensors and fabricate the wiringharness.

Follow along as a weekend, shadetree wrench spinner brings a 42-year old ride into the age of ElectronicFuel Injection.

Affordable Fuel Injection’s TBI kits are quite complete andfeature high-quality GM components. The custom kit for theNailhead included two 4.3 throttle bodies, Electronic ControlModule (ECM), dedicated wiring harness, fuses, relays, man-ifold adapter plates with gaskets, fuel pump with lifetime war-ranty, Oxygen (02) sensor and mounting boss, ManifoldAbsolute Pressure (MAP) sensor, Engine CoolantTemperature (ECT) sensor, fuel inlet/outlet adapters, check-engine light, Assembly Line Diagnostic Link (ALDL) connec-tor and comprehensive instructions. Most AFI TBI kits includea distributor. But in anticipation of the updates, I had alreadyinstalled a compatible MSD Billet distributor, MSD Blaster 2coil and MSD 6A ignition. The system uses the 6A’s tach out-put to trigger the ECM.

Saying the conversion wasdone in a one-car garageisn’t exactly accurate. It’sactually a 2-car garage with a 20x6’ shop attached. One bayhas been occupied (for far longer than I like to admit) with ourother project. The LS1-powered 1957 Chevy 2-door sedanserved as a “temporary work bench”. So, for all practical pur-poses, let’s call it a one-car garage. Some of my car buddiesscolded me for piling stuff on the ‘57, They reminded me howmany hours and how much dough went into making thesheetmetal laser-straight and solid. I wouldn’t recommenddoing this. Even with the cargo blanket, I will have to dealwith some dings when it’s time for paint. But hey...a guy’sgotta’ do what he’s gotta’ do.

DIY

EFI

cont.

DIY

EFI

cont.

I started under the hood. Here, the TBs are temporarilymounted on the adapter plates and intake manifold.Although the fuel inlet hoses are the high-heat-resistantfuel injection hoses, I might replace them with better-look-ing flex hose. I re-routed the heater hoses. They ran closeenough to the throttle linkage to make me nervous. I used3/8” and 5/16” barbed angle adapters to send the linesaround from the heater core to the passenger side. Notethe unsightly wires along the upper firewall. The EFI sys-tem wiring exacerbated this problem. I will clean them uplater. Hey, don’t knock my bright blue, angled-boot plugwires. They allow a better view of those rare, finned-alu-minum valve covers (which, admittedly could stand a goodpolishing).

Here’s where the ECM(computer) lives

The harness runs under the carpet below the AC evaporator.

It enters the engine compartment through a grommet in thepassenger-side firewall.

I considered using one of the factory “idiot” lightsfor the system’s check-engine light. But decided toinstall the included light in a visible spot.

The ALDL diagnostic port is mountedbelow the dash.I tested to make sure itclears the knees.

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EFI

cont.

The “dirty work” went on underneath. I envy those folks on those car-build-up, so-called “reality” TV shows. How easy it must be with their climatecontrol, high-ceiling shops, vehicle lifts, free parts, large crews, sponsor-ship and big budgets. Try hours of lying alone on your back, on a coldgarage floor, with dirt and rust constantly dropping in your eyes (the safetyglasses kept fogging up) and a drop light that never seems to be facingthe right direction. Now THAT’s reality!

The 12-15psi electric fuel pump was installed at the floorboard. Thein-line fuel filter is right ahead of the pump. I spliced both right into theexisting 3/8” dia. fuel-feed line. I tried using the existing 1/4” dia. fuel returnline. It was too small and caused the return-line pressure to be much high-er 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 pro-tect the pump, filter and short length of rubber lines from road hazards.

All my sheetmetal fabrication is done with a pneumatic cut-off tool, hand shears, a file, an anvil and a MIG welder. No fancyEnglish wheels, metal brakes, plasma cutters, bead rollers or TIGwelders. Although I was taught to use most of those tools by thelate, legendary racer Buddy Morrison. I was a member of theReher-Morrison Motorsports NASCAR Craftsman Truck teamformed by Morrison in ’97-’98.

Anyway...the factory 1/4” line ran into an orifice in the top ofthe fuel sending unit. I dropped the tank (after draining nearly 20gallons of gasoline), capped the 1/4 inlet and fabricated a returninlet into the filler neck. I could have filled the tank with water andsafely MIG-welded the 3/8” dia. steel nipple into the filler neck.But draining all the water from the baffled tank would have beena much bigger chore. A rubber grommet and Liquid Steel shoulddo it.

Don’t fret. The rubber return line (top arrowabove) goes behind and above the mufflerwith the tank in place. I wrapped it withhigh-temp. heat shield, just in case.

Here are my low-buck, handmade road hazard protectors for thefuel pump and filter.

“A rubbergrommetand LiquidSteelshould doit.”

—D.J. Adams

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cont.

Using the air cleaners from the old carbs tooksome adaptation. I added 1” spacers andnotched the chrome tops for the injector-sensorwires. The filters are from K&N.

The Engine Coolant Temperature (ECT) sensorwas threaded into a reducing bushing, wherethe original sensor entered the manifold’scrossover.

Here’s a closeup view of the sensor for theIdle Air Control (IAC) valve. There is one onthe base of each throttle body.

The Oxygen (02) sensor is threaded into aweld-in boss in the passenger-side head pipe.

The Manifold Absolute Pressure (MAP) sensoris mounted on the firewall, towards the cowl.

The Throttle Position Sensor (TPS) connectsat the base of the rear throttle body.

The MSD 6A ignition box is on the driver’s sideinner fender. The tachometer output (arrow)provides the trigger signal for the ECM.

I had to cut and drill the throttlelevers in order to fabricate acustom linkage.

“Do I havethe skill toproperlyinstall thesystem?”

—D.J. Adams

DIY

EFI

cont.

Here’s the finished underhood installation. As I mentioned, I might consider replacing the rubber fuel lineswith shiny flex hose. The valve covers could use some polishing and the engine is begging for a new coatof paint. But I’m really looking forward to doing what the car was made to do: driving! At this point, I havehad the car on jackstands for nearly three months. After all, it was a spare-time winter project. A mechani-cal 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 wework out some little bugs (an open-loop 02 sensor code and slightly rich idle) and fine-tune it, it’s time to hitthe road and enjoy the aforementioned benefits of Electronic Fuel Injection.

Finishing up.

Next up: computer tuning and road testing.

SOURCE GUIDE

Affordable Fuel Injection7575 N. Hollister RoadElsie, MI 48831248-393-1621www.affordable-fuel-injection.com

Questions? Thoughts?

D.J. .AdamsAdTex Advertising817.244.5054www.adtexadvertising.com