nopistonsPWR

i just got a 89 gxl...not running.... all he said i needed a fuel pump...so i replace the fuel pump. change the fuel filter dump the old gas out put some new gas change the oil....because its been sitting there for a while...the thing is the car has an S4 motor in....and he did say it was running before...

so i started the car and it started to run sometime and sometime not but when its running it doesnt seem like the full potential of the car... when i step on the gas pedal it accelerate slowly and the rpm drop down slowly... so when i take out my top two spark plug...the top right one doesnt seem to have any burnt mark like the top left one.. any idea...??????

RotaryRocket88

iTrader: (7)

How bad did the fuel pump & sock look when you took them out? You could still have rust/dirt/other crap in the lines, and that just plugged up your new fuel filter.

nopistonsPWR

but even tho if the fuel filter is plug up....than how the car starts in the first place....???can it be the tps?

RotaryRocket88

iTrader: (7)

Fuel demand is lowest at idle, so maybe it's just enough volume to get by. It's not like any TPS problem I've heard about, but you're welcome to test it. My bet is still on fuel delivery.

Is the motor a S4 block w/ S5 manifolds/electronics? Or is it fully S4 with adapted wiring? If it's the later, you'll need to make sure the EM harness was altered correctly. Series swaps are a wiring nightmare, and the previous owner might have gotten the car stuck in limp mode if it's still using a S5 ECU.

nopistonsPWR

its a s4 block with s4 manifolds. im not sure if its the s4 harness adapted with the s5. how can i tell the difference? but he said the car was running before

RotaryRocket88

iTrader: (7)

S5 electronics. Vane-type AFM, double TPS, electric OMP. The OMP is the main one to watch out for. If the previous owner didn't swap the front covers/OMPs, and you've got a mechanical one, the car will go into limp mode. That is IF the ecu and wiring are still S5. Pull the passenger side kick panel and see if the ecu is N326, N327 (S4). That'll be the first hint.