Cannot pull codes! (car runs awful)

[tmielnichuk]

Hi All,

Here is a breakdown of a recent problem with my 89 SHO. This started about 1 month ago. It runs terrible upon a cold start in the morning. Almost sounds like a bad miss-fire or dropped cylinder. If I tap the throttle before it warms up it dies out. When I try to restart I have to floor the gas while cranking for it to fire again. Once the car is warm, it knocks like crazy under load at lower RPM (2000 – 3000 RPM). I am using 91 octane gas. I tried to pull the codes today and couldn’t get either the KOEO or the KOER to work. I have pulled codes before and they worked fine. I tried several times to get the codes but it won’t even attempt to run the tests. Here is a list of what I have replaced on the car if it helps:

CPS
TPS
IAB
Plug wires
Plugs
Valve cover seals\ plug well seals (wells are bone dry)
Fuel Pump
Fuel Filter
Fuel Pressure regulator
Alternator
Water pump
Battery

I do know of a couple things which may have caused this problem but I’d like some feedback before dumping more money on this car.

I was driving the car last summer when the battery ground wire to the starter motor shorted out and ENGAGED the starter while the car was moving at highway speeds. It caused a ton of noise and sparks from the wire to the frame. Could this have shorted out the computer?

The fan relay does not work anymore, and I had to wire in a toggle switch for the fan. Does that mean that something else in that relay module is screwed up?

I am getting awful gas mileage since this problem began and the car smells like it is running rich.

How can I tell if the computer is shot? Does it reset to a “default” mode if it gets damaged?

Sorry for the long post but I am at a loss since I can’t pull the codes off the thing!

Thanks for your help guys!

 

[F-22 Raptor SHO]

2 things:

1: you can try to reset the computer by disconnecting the battery and then turn on the headlights for 10 min to drain all power. Reconnect battery and see if you can run codes then.

2: Swap in another computer.

The only time I have seen problems where someone couldnt pull the codes, it was due to a bad computer. How it got bad was a mystery, but after changing it out, everything was fine. Initial problem of no idle was fixed.
It is easy to swap out your computer and see if this fixes the issue.

Hope this helps.

Any other folks want to chime in?

 

[tmielnichuk]

Computer reset didn't help at all. Tried it a few times!

Anyone out there in the Victoria BC area have a 1st gen that they wouldn't mind swapping computers to see if this fixes my problem?

Keep the suggestions coming!

Thanks guys!

 

[F-22 Raptor SHO]

just to nip your next question in the bud, the computer is very easy to remove. Under the hood there is 1 bolt in the middle of the harness that you loosen. Behind the glovebox, there is a white plastic clamp holding the computer up to the fire wall that taks a really small wrench...dont have to take the tiny bolt out, just loosen it a couple turns if that and the clamp comes right off.

I'm not saying your computer is your problem, but u should be able to run the codes if the computer were ok.

There is another way to clear the computer by pulling out your paperclip/wire/whatever u used to run the codes while the test is being run, but you are not having any success even running the test at all.