1988 Other Chevrolet Models engine flooding

You may have a blown gasket on the bottom of the TBI and the computer is trying to make up for it or your return line to the gas tank is plugged causing it to flood.

The only thing I can think of is that your fuel pressure is to high or yur injectors is bad. Maybe teh tps switch is stuck as well. You might try cleaning it with choke cleaner. With TBI your fuel pressure should be around 11p.S.I. If I can think of anything else i'll contact you.

Ok I had to go back to the manual and see how the beast operates. The TBI is controlled by the ecm. Unfortunately yours has what is called a prom inside it. If the ecm or prom isn't working right it could cause this. But your best bet is to get a wiring diagram and see if any references are being sent back to the computer or not and causing the ecm to flood the engine. The only thing that I could think of is to get a prom or ecm from the same type of truck with the same type of engine and put that ecm /prom unit in and see if that cures it. Try to find one that you can just use instead of buying. I doubt that you will be able to find a prom for that vehicle nowadays due to age. The prom goes inside the computer. Maybe if you can find the prom you might try changing that instead of the whole ecm.

If the dealer used the same prom that goes in the computer it would do the same thing. I"m sure you have checked for engine codes first. You would have to get a different manifold. One other thing labout TBI units. The vacuum hose going to the map sensor is often soft or leaks. Also you have said nothing about the TPS switch. If that is stuck in the wide open position then it will tell the computer that it needs fuel all the time, causing the flooding. I am assuming that in all this time there hasn't been a timing problem like with a timing chain or distributor being in time as well.

The only other thing I can think of would be air blockage. I know that has an air cleaner similar to a carb. If it is blocked or cut down it wouldn't get enough air into the engine. That would include checking the vacuum motor ifyou have one on the air cleaner and it wouldn't open. Also if you happen to have ACCEL spark plugs in your truck get something else like ac champion/NGK, one of those brands. I've never had good luck with ACCEL plugs. I really can't think of anything more. Unless there is a valve/cam problem and they aren't opening all the way.