I have an 88 305 TBI. When started the engine revs high and then dies. When the problem initially started, I could keep the engine running by giving it a little gas, but the revving up and down would continue. Now I cannot keep it started. Everytime I start it it revs up and dies, whether I give it gas or not.

The only exception is when I disconnect the vacuum line form the MAP sensor, the engine will level out and run for about 20 -30 seconds before it dies. The only error code I am getting is 33 (MAP sensor).

So far I have replaced the MAP Sensor, TPS, IAC, TBI gasket, manifold gasket, and fuel regulator diaphragm, EGR gasket. None of the repairs have made any difference in the performance.

The engine seems to be running lean. I can keep the engine running by spraying carb cleaner in the throttle body. I tried to check the fuel presurre by placing the gauge in the top line that leads into the drivers side port on the TBI and got a reading of zero. I don't know if this was the right place, or if I need to pinch off the line in another area to get a reading, or if it really is zero. Injectors look they are spraying a good cone of fuel.

Please Help!!!! I am out of ideas!!!

 

I think I have the same problem with my 305 TBI I have a video of the RPM as it revs up and dies http://www.youtube.com/watch?v=8toyz91QCiA seems like alot of people think I have a vacuum leak

 

the fuel pump pick up tube to fuel pump has a small rubber hose that tends to crack and leak over time. it causes the car to do that. mine did for 3 months till i just up and changed the pump. that's when i found the broken line. i did all the same stuff. had a great cone coming from the injectors but no matter what it wouldn't run. now its been over a yr without any problems. good luck!

 

I had a 82 trans am with a 90 tbi motor that did this. if I held the rpm to 2000 rpm for a legth of time the exhaust would turn bright orange from the cat back to the muffler. fuel pressure was at about 8psi it was later found to be the soft line between the fuel pump and sending unit had a cut in it. this also triggered a lean code in the ecm but the car pulled the same idling stuff yours are doing. A tpi pump and new soft line fixed it and the problem never returned.

another problem it had was a injector wire that wasn't getting a good connection and it again did this weird idle crap.

 

Where is the fuel pump locatated that you changed Jeffs82TA, is it the pump ontop of the fuel tank or is it something in the engine compartment. (srry im a noob im only 17 and just starting to learn about cars)

 

in tank

 

ok so i will have to drop my fuel tank to change it?

 

A simple answer is yes.

 

you don't have to drop the tank just lift the car off the tank ....

you know another thing that caused my tbi to also die, the egr valve is different, something to do with normally closed/normally open something to do with vacuum anyways if the wrong egr will cause the problem as well.