need your help guys. bought a 92 rs 305 tbi w/5spd trans. engine pulses very bad at an idle until it warms up, and even then it wont take the gas to move.. if i unplug the map sensor it does much better but not good enough to drive. ive replaced the map, and sprayed looking for vacum leaks with no luck. any suggestions? thanks

 

I had similar prob with my 92 tbi It turned out to be one of my
plug wires. It looked fine but when I went to change them one of them fell apart in my hand. new plugs and wires---problem gone.

 

Common problem, keep checking for vaccum leaks where the TBI meets the Intake Manifold, as well as all vaccum lines. If the vaccum lines are cracked or brittle replace them. Also, check/replace Cap & Rotor, Ignition Coil, Plug Wires, and Plugs. I'd also check the fuel filter and injectors to make sure neither is plugged up. Good Luck!

 

also i would get my egr checked too while you are there.

 

I would also agree with the egr problem and checking the ignition system.

Steve

 

Ditto on the tune-up. These cars tend to get negleted over the years and many of them are running with clogged ERG valves and non working 02's. Check all vacuum lines for splits of cracks as well.

 

i think the guy i got it from suspected the tune up problem. it has new ignition components, new egr and a new map sensor on it. i changed the fuel filter but nothing changed. I ordered a throttle body off the net to try that (got it cheap so i thought why not). If you watch the flow through the injectors, it sprays quite well, but every few seconds both injectors begin spitting like its running out of gas. Anyone know what the fuel pressure should be for this engine? It did sit untouched for about a year in a garage so i was thinking maybey the pump is gummed up up something.

 

does sound like your fuel pump bro. i would go to autozone and get some highoctane booster maybe like 108 and pump some cheveron gas use the best one they have and try that out before you go buy a new pump. plus doesnt really hurt to try.

 

Ya, I need to beef up the pump a bit anyway. I just purchased a 200hp NOS system that requires added fuel pressure. I just wanted to get the car running good before putting it on ofcourse. If all else fails, i have a couple tpi kits that are just collecting dust. i could put a tpi on it (if i can find an affordable harness) and just lose the tbi altogether. Ill try the pump first though, thats alot of work i dont wanna do just yet

 

You can test the feed line fuel pressure. They have testers that you can rent. You shoul dbe seeing around 9 to 12psi to make a stock LO3 run. A new fuel pump is always a good idea with these cars seeing how the stocker is so lame. Don't give up on TBI yet. You would be killing any future power production with the stock GM TPI.

 

Yeah, the tpi ive had in the past didnt produce much power, just looked cool. When this car was running right it would really move. Ive learned that it has a 4:10 posi rear end in it, some hi dollar 11" cluth/plate, underdrive pulley set, and a hypertech(i think i spelled it right) prom? ecm? something to do with the ecm is hypertech. For no more than the car is, it ran really good. I'll put a pressure test on it and see what it comes up to. Thanks