BrettJ

Okay i have a 91 ls i picked up last month. It drove great until one day the ignition lock cylinder went out. once i changed this the starter went out. So i took on the challenge and successfully changed the starter, changed all intake gaskets, changed the radiator due to a friend breaking the upper hose piece off, and i have everything put back together. Car starts and will run but it runs really rough, the exhaust sounds louder, backfires, sounds like it could be loading up, the transmission feels like its slipping, and feels as if its way under powered. i have checked codes in which it came up with 4: 14(ignition #1 signal) 24(intake air temp sensor) 31(air flow meter signal) 47(sub-throttle position). im kinda frustrated with the car at the moment and just wanting to see if theres something ive missed maybe.

dicer

Welcome to old cars with EFI.

djamps

Maybe a harness is pinched or unplugged? All of those codes seem to point to sensors/wires around the area you were working on.

sha4000

iTrader: (1)

Go back over your work area and make sure ALL connectors are snug and no pinched wires.

BrettJ

Yeah i have checked every sensor at least twice. I have changed multiple sensors. It is still only throwing one code which is 47 (sub TPS). i have changed it out and it didnt changed. i have followed the harness and haven't found any issues with the wiring. It now idles fine although the second you try to give it gas it starts to sputter and dies.

dicer

So you changed the sub tps? And where is that? Is this a Trac car?
The codes don't always tell what the problem is, something else can happen to cause the code. Did the CEL come on?
Really rough ? So if it idles good now, then its not running rough anymore? Need some clarification on whats going on?????

BrettJ

Yes i have changed the sub tps. It is a Trac car so it is next to the tps. yes the CEL light is on for the sup tps. it idles smooth now until i start to give it gas. it runs rough but idles smooth. i have unhooked every sensor anywhere near the intake while its running and nothing effected the idle. it starts and idles fine without the intake sensors plugged in. could this be an ecu problem?

dicer

How are the plugs for the trac motor wires? I think that throttle is closed and causing the problem. And that is why the sub tps code too. Just a wild guess.

BrettJ

what exactly do you mean by the trac motor? is that the sensor on the back side of the throttle body?

dicer

Yeah I goofed there is more than one. I mean the one on the throttle body.

bdazzler

I would suspect the ECU (aka ECM) first and foremost, unless you know the capacitors have been replaced...

BrettJ

i have finally figured it out. It was the fuel pressure regulator. i replaced it and it seems to run great now.

djamps

Nice work!!! Glad you were able to find the culprit.

Stereorob

my 94 backfires and spits flames out when it does. its quite the sight/sound. not sure what is causing this.

bdazzler

Could be a variety of reasons, e.g. bad coil, bad sparkplug wire, timing is off. Did you try to find an error code?