My 88 t/a 305 tpi. Purchased a 1987 5.7 tpi out of a vett. Computer and all went into trans Am.. now it blows gas out exhaust. Runs good but smokes black smoke. Shop has no clue what's wrong

 

Sounds like you have a stuck open injector on the new fuel rail. A simple fuel pressure drop test should confirm

 

thank you.. I ordered a pressure checker
I have been concerned that it could be wrong chip in the ecu..

 

Didn't the chip, come w/the 'puter...that came w/the engine?

 

Yes sir. I got ecu and chip... Tried both in car.. it's just running rich and blowing black. I wish I hadn't swapped the engine now but we wanted a fun car. New plugs , wires, and cap. Sorry it took a while to respond. I'm learning how to use this site. Thank you

 

It seems unlikely that the ECM from the 'Vette would have the wrong chip, for the 'Vette engine. I'd be investigating other possibilities. Do you have an OBD I scan tool? Can you data stream or data log?

 

No sir. I'm wanting to buy a OBD1 reader. No cel on and shop that did the work said it had no codes. I do have a fuel pressure gage reader on way and now will look for a code reader. Thank you please don't give up on me.

 

I checked fuel pressure and it's at 40 lbs. When I shut off car it doesn't drop. So that tells me it's not leaking injectors. But this thing is blowing black and drips fuel from exhaust. It runs good. Starts great and idles good but can hear it loading up..

 

Is it possible the fuel is not getting burned? valve timing off somehow, intake valves not sealing, some weird thing like that. or too much fuel being pumped in and a complete burn doesnt happen. all those add up to engine not running good tho.....

 

If it is not a mechanically stuck injector, it could be an electrical issue. If one side of the injector harness is inadvertently grounded, the four injectors on that bank would spray fuel constantly whenever the ignition power is on.

Such a short could also be in the injector driver (transistor) for that ECM output.