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I discovered a rather weird issue with my GS this weekend. Its not a huge surprise to me that there is a issue with the wiring of the car considering everything I have done to the harness upto this point. But this is such a strange issue that I dont think its anything I have done to create the problem. So I figured I would post this up and see if anyone has run into this issue before. I know I can track this down via my shop manual, ECU pinouts & wiring diagrams.. but before I invest that much time and work into this issue.. I figured I would see if its something that has a simple fix to it. So without further delay, here is the issue...

Everytime I turn my key "Off" for more than a few moments.. the ECU loses its settings and the clock resets itself.

Why? I have checked the fuses under the dash.. all good. Havent checked the ones in the engine bay.. will do that tonight after work. I havent hacked into the ECU wiring harness at all.. and I think everything is plugged in as it should be.. I mean the car starts and runs and if I let the car run for 10 minutes or longer it relearns all the info and drops down to proper idle speed.. though the idle does hunt up and down slightly during warmup between 1500 - 2000 rpms. After 10 minutes or so of this.. the idle drops to normal 850 on the nose. But if I shut the engine down.. 5 minutes later it doesnt remember any of that.. though it doesnt take as long for the ECU to get back to "Normal running" as it does when the engine is cold (I figure that seems normal as well).

Now if its not a fuse in the engine bay.. I am lost and all I can think of is to pull out the shop manual and wiring diagrams to find the wire that is supposed to be providing the ECU with constant power and trace it down and find out why its not. I was just hoping there was simpler solution that someone else may have already come across. Thanks in advance.

Tunes67

if it was just the ECU resetting I would say probably a wire... but since the clock is resetting I think you are right about the constant power wire to the cabin. I'm not sure about a fuse because if that was blown you wouldn't get power at all to the cabin. right?

does your GS have a radio in it? does it reset also?

Maybe a ground came undone somewhere? did the GS have any kind of aftermarket alarm system before you got it?

No ground wire undone anywhere I can see under the dash.. and the stock radio was gone when I got the car. Just to add to the weirdness.. if you open the door.. the factory automatic decapitator (passenger side auto seatbelt.. drivers side has been converted) still functions as it should.. so there is still constant power to the cabin cause you dont have to turn the key for that to work.

Another side note.. the passenger side window switch and power door lock stopped functioning at some point as well.. this just gets weirder and weirder the more I think about it. But I dont think they are all from the same issue.. I think there are 2 or more problems in the cabin that need to be resolved.

Tunes67

My 92 RS does the exact same thing with the clock resetting. I just deceided to finally search and see if anyone else had this problem and found this thread. Let me know how it comes along and if you get it fixed cause id like for mine to work but its not that big of a deal just something i wish would work.

I haven't read your worklog in a while. What have you messed with or changed re. the harness?
I would bet a ground too since you get power, but are loosing it when you turn the car off. First I would check for 12 volts in the radio harness with the car on and off. I cannot remember which wire it is suppoosed to be off hand, but if it is out and there are not that many wires to begin with it seems like an easy spot to start checking. If there is no power I would start by looking at the chasis grounds (all easily marked and usually grouped). If they all look clean and ohm no resisitance then I would go back to the radio and start testing that ACC power in reverse from the plug to its terminal.
I wouldn't try and run the car much or leave the power on for long. If you have a loose ground it is going to create heat and mess with anything electronic. You don't want to be looking for a new harness or some elec. part like a ECU or god knows what else.

I agree in large with PATDIESEL. Its sounds like its a GROUND issue. Go through the wiring With the car on, wiggle around the wiring harness, it might lead you to the source!.

Not sure if this is relevant to your issue but with my 92 RS i pulled out the stock radio to put in a stereo i just got cut off the plug and my clock stopped resetting and has worked ever since. Not sure what was going on there though.