Our 88 Vette has a gas rich exhaust odor. What causes this?


Asked by Apr 24, 2010 at 08:13 AM about the 1988 Chevrolet Corvette Convertible RWD

Question type: Maintenance & Repair

Just bought an 88 Vette convertible that was garage parked since about 2003. The car has 73,xxx miles and looks good inside and out. All accessories work, engine runs decent, auto trans shifts good, no check engine light on, but smells like she's running rich. Will do a complete tune up, change filters, fluids, belts, hoses, maybe brakes lines if needed. Maybe she needs a good run with fresh fuel, to let the computer reset since the battery was changed and the car was trailered to my garage? Suggestions?
Thanks, Bub

7 Answers


Begin with fresh fuel and inj.cleaner,is it doing that all time or just at start?


Hey Marcel Yes, we filled up with Fresh Premium and poured in some "Lucas" Fuel System Treatment with Injector Cleaner for the 25 mile ride home in the "new" car. Then I cleaned out the air filter box and will get a new filter element. The odor is still present but not as strong & the car starts better already. A full tuneup is on the schedule. Also the Radiator Electric Fan died. The temp sensor works, so I'll check the relay and Fan motor. Nedd to find where the relay is. I guess its the one ahead of the battery on the drivers side fender well with the wiring the goes back to the fan and temp sensor toward the front and other wires running toward the firewall. I also guess the fan should kick on at about 195*. Maybe its just bad wiring connection since it looks like someone worked on this circuit before. Thanks for the advise!


Any smoke when you start it?especialy cold (black smoke)


Marcel No black smoke at all at cold startup, no leaks, or smoke while warming up, just a gassy fume odor from the exhaust. I think a good tuneup, PCV, air filter, etc. and a few miles down the road with injector cleaner will help. All cylinders are firing as is. Thanks, Bruce


Mid gen C4s are notorious for bad Multec injectors. Injector cleaner is not a good idea, it is not recommended by many Vette 'gurus'. If a good blowout does not resolve the problem, you really should look into replacing the crapola Multecs with something much better, like FIC.


Sitting for so long, you may need to look at a rebuild on the fuel delivery system as some of the old seals may be deteriorated. Don't delay too long as it will cost more after the fire to fix than before.


I have the same issue, I've done everything to my engine from tune-ups, flushing, etc. I was told by many master mechanics that "this is a C4 Corvette, it's normal to run rich, this is how they're made." And everything runs great, no codes\clear.. I've had everything changed out and it still runs rich.

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