Fuel Injection Failure? Cut-n-Paste a Carburetor!

When you race at night, after the parts stores and junkyards have shut their doors, you need to get resourceful when facing mechanical failures. Sometimes another team running the same type of car as yours will loan you parts, but what happens when you’re the only team at the race with a Plymouth Sundance Duster, the EFI system craps out at 10:00 PM, and nobody else at the track has any Mitsubishi 6G72 parts lying around? You could pack up and go home… or you could do what the United Partnership of Pentastar Racers did at the 2014 Doin’ Time in Joliet race and pull off some Soviet-style field-expedient engineering!

The UPPR Duster has been reasonably quick and depressingly unreliable during its LeMons career, suffering from a broad spectrum of the woes that tend to afflict race cars based on the Chrysler K-car platform and/or powered by Mitsubishi engines. This does not prevent the UPPR— whose members are engineers who work for Detroit car companies— from having a good time on race weekends.

As Billy Dee Williams doesn’t quite say, the Duster almost works every time.

So, the UPPR Duster’s fuel-injection system spent the first part of the race getting flakier and flakier. The team tried replacing injectors and various sensors, futzing with the timing, and the usual shoveling-back-the-tide futility that you do in situations like this. Finally, team captain Andrew Bayley realized that there was no way to make the car run with the parts on hand, and he dropped by the penalty box to see if I knew of any other teams who might have 6G72-related parts available. I didn’t, but I had a (not so) brilliant idea: block off the throttle-body opening, cut a hole in the big table-like top surface of the intake plenum, and bolt on a carburetor. I’d been trying to talk teams into this sort of fix for years, because I thought it would be hilarious to watch work well enough, and now— finally!— someone was going to try it.

The Nobel laureates of Apocalyptic Racing were pitted near the UPPR guys, and they offered an extra Aisin 2-barrel carb they’d brought for their oft-broken Celica’s Toyota 22R engine. A low-pressure fuel pump and adjustable fuel-pressure regulator were scavenged as well, and the fun began.

A little Sawzall work, a few holes, some fuel plumbing, and much kludging of throttle linkage later, the carburetor was in place.

A hood-clearance problem became apparent, and the UPPR crew made the needed adjustments.

With the checkered flag just minutes from flying, success! The Duster roared onto the track and ran perfectly for the rest of the race. Well, OK, so what really happened wasn’t quite as glorious: the car ran well enough to get onto the race track, but the team had used RTV gasket sealant to close the carb-to-intake gaps (because that’s what they had available), and the stuff melted after a couple of laps. The resulting massive vacuum leak had a negative effect on performance (to put it mildly) and that was the end of the United Partnership of Pentastar Racers’ efforts for the night.

For following my advice in the face of ample evidence that this is a terrible idea, the United Partnership of Pentastar Racers received a special trophy: the Never Listen To Judge Phil Award. Note: Mr. Bayley informs us that the problem that killed the EFI system was the allegedly “fuel safe” sealant used to “seal up the trap doors on the in-tank fuel sump” (it wasn’t fuel safe), clogging the fuel injectors. This would have clogged the carburetor eventually, but does not detract from the glory of this repair.

Something to Say?

7 thoughts on “Fuel Injection Failure? Cut-n-Paste a Carburetor!

  1. That’s really unusual. I have to say that my mother had an ’89 Dynasty that had well over a quarter-million miles on it when she finally decided to retire the car. She flat out loved the thing. We only ever had problems with the transmission and the cassette deck. Luckily, the transmission always decided to pack it in within limping distance of home. Never on a trip did it decide to quit. But the fuel injection never once caused us any grief. I’ve even had a couple of Turbo 2.2’s and the EFI on them has never ever caused me any problems. Shame to hear the UPPR was having such issues with it.

    I never would’ve thought to put a carb on like that…. especially with RTV. Kudos for the effort!

    1. Funny, my mother had an 88, we had no problems with it in 12 years, though we had the v6/3spd combo that I think was unique to 88 (the first year). We sold it to a neighborhood kid in 2001, who promptly totaled a Taurus with it. The Dynasty lived on, albeit sans it’s crosshair grille and with a 5 degree bend in the frame that nobody but me could see just behind the front wheels.

  2. Recently, pretty sure I was the only one backing a guy on comancheclub.com when he proposed ditching the EFI system and dropping back to a 2 BBL carb. My position is this…. all the sensors and crap are only going to be offered for so long. Maybe you can buy a few years moving to an HO from a 96 & up XJ or TJ to keep you going. But actually it’s the inventiveness that makes this automotive addiction fun.

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