SC Computer going bad?

91BLOWNSC

Registered User
Have any of you guys had any trouble with your computers before? My car seems to stall after it goes into "closed loop" which is what happens after it gets warm...and it stalls as soon as the computer takes over. So i cleaned the connections on the computer and it was fine for about 2 months. Now the problem is back again. It kept stalling. So I cleaned the connections again, and it stayed running the whole day until the end when it stalled. I don't get it. I thought either a computer was BAD or it was GOOD. I have a rough idle, and my AC compressor kicks on sporatically. What the hell is wrong with my car.
 
hmmm...

Well went it stalls all the default settings of the car comes on. The engine fan comes on to cool the engine, the climate control automatically turns on, and when i go to restart it and just have the key in the forward position...the fuel pump won't turn on. I have to wait about 5-10 minutes for the car to cool before it will start again. If I had a short in the wiring harness...how in gods name would someone fix that?
 
Unfortunatly its a big pain in the *** but you have to spend alot of time with a VOM testing every wire till you find them.
If you dont have the AC turned on but yet it comes on you pretty much have to have a wire shorted somewhere in the harness.
The comp doesnt control the AC except to turn it off when you go WOT.

EDIT:
You can try wiggling the harnes when the car is acting up to see if you can get it to stop. That may help tell you the vicinity where the problem is.
 
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hmm..

Already sounds like a plan I will have to try. But what about my car stalling and idling so rough and then just quiting. Could the computer be screwed up along with the short? Could the computer cause such rough idle and missing?
 
Well the thing is until you rule out the possability of a shorted wiring harness you have no way of knowing what else could be wrong. If you infact do have a shorted wiring harnes some of your sensor wiring may be involved and that could be your entire problem. However you may have more than 1 problem at the same time.
I'd start by looking for obvious damage to the harness. You may find a melted spot or something pinched.
 
MIKE 38sc said:
Well the thing is until you rule out the possability of a shorted wiring harness you have no way of knowing what else could be wrong. If you infact do have a shorted wiring harnes some of your sensor wiring may be involved and that could be your entire problem. However you may have more than 1 problem at the same time.
I'd start by looking for obvious damage to the harness. You may find a melted spot or something pinched.

G's this drives me nuts. After having my car down for so long with a fresh tranny and engine rebuild, I just want to drive the damn thing for 2 minutes without it quitting on me!! Your possibility of a bad wire was something I never thought of. I dont' know if its the fact that I clean the pins and connector or if its that I move the harness and maybe I unkink a broken wire or something. I will have to give that a shot next time.
 
G's this drives me nuts. After having my car down for so long with a fresh tranny and engine rebuild, I just want to drive the damn thing for 2 minutes without it quitting on me!! Your possibility of a bad wire was something I never thought of.I know what you mean. My poor bird has been down for about 2 years now and its killing me. But what can you do? Life throws you curve balls and you can only do the best you can.

I dont' know if its the fact that I clean the pins and connector or if its that I move the harness and maybe I unkink a broken wire or something. I will have to give that a shot next time.Well now see, now more of the story comes out. I did not know you pulled the motor and tranny and its very possable that some wires broke or the insulation broke allowing shorts between wires. I was just out in the shop looking at my wiring harness. I know its a disaster in the making. All the wires are hard and stiff from all the years of heat cycling. I'm seriously considering rewiring the engine bay. I dont know for sure I'm gonna but I just may. First I need to strip all the black protective tubing off the wires and see what kind of condition there in. I'm trying to figure out howw to get the harness completely off the car so I can get my engine bay painted. I figure while its off that would be a great time to build a new harness using silicone jacketed wire so heat would no longer be a problem.
 
Just to throw another thought into the mix...

The fact that cleaning the EEC connections clears the problem temporarily, the problem, whatever it is, must be local to that area.

The next time you remove the EEC, unscrew the cover and make sure the board is mounted firmly to the case and the board/case ground is not corroded.

From you're description of when it stalls, it sounds as if you're losing your ground to the EEC. Ohm the incoming ground in the harness connector to the chassis and try moving the cable up & down to see if the continuity changes.

I don't have schematics, or I'd try to point you to the best places to check the grounds. Maybe someone else can help with that.

Lee
 
just a thought.

yes it does seem likely that the problem is near the computer, seeing as the problem was temporarily resolved by cleaning the connections, but

the 3 problems you mentioned, the fan coming on. A/C coming on, and fuel pump problems, leads me to believe you may also want to check out the IRCM (mini comp. by the air box). All those items are controlled there.

now obviously there is a connection between the IRCM and the regular computer, so it is still very possible that you have a wiring problem near the main computer.

I highly agree with a grounding problem.

jim
 
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