i recently purchased a 1988 firebird 305 tbi from a family member sight unseen. after towing this car home, i started it up and found the problems he ran into. now i either fix the tbi unit or run an intake carb setup. i know carbs i know nothing about tbi but am willing to learn. where can i go to research tbi? by the way, the car runs good at idle but smokes like the dickens (fuel) after removing the computer with the hyper chip and reinstalling one from a chevy truck with a 305, this helped the fuel problem but you still cannot get your foot in the gas as this causes the engine to bog down. 18psi fuel pressure at the throttle body and the vacuum is good. new plugs wires cap rotor coil. map sensor checked out good and like i said, it idles good. give it throttle and it stumbles all over the place.

 

Just do searches on here for your problems. And welcome to the forums!
Im not much help to your issues, but im sure other people will chime in.

 

The simptoms you describe sound like too much fuel.
Stock thirdgen LO3 tbi ful pressure should be 11.5 psi. Some mltipliers need to be changed in the chip for higher FP.

18 psi is to much fuel for stock engine+full exhaust.

You could adjust the FP to 11.5 psi and see what happens. Also do some reserch on the ECM you are using to find out for what FP its tuned.

If you still have the original ECM im sure you could find a stock LO3 thirdgen chip.

 

the exhaust has been chopped right before the cat and left open (brother in law thought the cat was stopped up). i also think maybe they put a 350 throttle body and injectors on this engine. after doing some looking around in this forum, i saw a thread where someone posted that a 350 injector is orange, where a 305 is green. the injectors on this throttle body have orange tint. also, after doing some checking, the control unit that came out in the firebirds and camaros with the 305 tbi also came in the impala and caprice with the 4.3. so you are correct about the fuel curve and map control in the 4474 computer i have now. i recently found a control unit on e-bay at a reasonable price and found a throttle body with green hued injectors. im going to try these next.

im a parts change expert. i may not know what im doing as far as diagnosis, but i sure know how to spend money and change parts out til i get it right. just wish i knew more about tbi and diagnosis. the monies spent could go into the performance instead of the running element.

 

ive changed out the throttle body to the good used one with the "green" injectors. ive done a compression check and all cylinders check in at around 145+-1-2psi. i changed out the spark plugs again and double checked the wires and firing order. 18436572. how do i check fuel pressure at the injector? also, where can i find replacement o-rings for the fuel lines into the throttle body? one last question. i noticed that my cold start problem is still there. i have to crank on it for quite a while before it finally takes off and starts. any ideas?

 

shot in the dark with the cold start issue. the oil pressure sender has to be to a certain point before it lets the car start.

 

I use this between the metal and rubber top fuel line next to the alternator.

http://cgi.ebay.com/ebaymotors/GM-TB...mZ250273992915

Rockauto shoul have the o rings.

 

received a ecm via e-bay special. awesome. worked perfectly. still cold start problem but at wot, revs snap like a rubber band. still going to fix the dist prob as soon as i find info on how its done. i hate to see cracks in things that shouldnt be. thanks guys for all the help!