Bad ECU?

Ok so the problem came up again with the car dying when I rev the engine. And the check engine light came back on with P0125. I replaced all the possible problems so I talked to a mech. and he said that it is most likely the ECU. Does anyone know symptoms of a bad ECU or do you know a good place to buy a new one?

Also if I need a new ECU do I have to get another one from a GSX? or can it be a GST? and does it have to be the same year?

Anyone?

P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control
 
****, I have no clue. I would check your MAS, make sure the harness is on good. Check for any boost leaks or anything like that.
 
Its possible that an injector isnt working right, or perhaps a plug isnt sparking right.
 
Usually you can tell if your ECU is bad. 90% of the time its your capacitors that go, and they are filled with a sulphur compound, and then they leak, it smells like rotten eggs, REALLY bad. If you arent sure, you can always open up the ECU, and it should be fairly obvious. Honestly, i doubt thats the case, but it is possible.

"In OL mode, the ECU reads all its sensors, checks with its programming to determine the desired A/F ratio, calculates the required injector PW (as detailed previously), then sends that PW to the injectors, hoping for the best. It never really knows if it achieved the desired A/F ratio or not."
-musclemustangfastfords.com

your car runs in open loop mode when your car is cold, usually for about the first 5 minutes or so after you turn your car on. this is verified by the engine temp. if your thermostat is stuck open, or you have a bad coolant temp sensor, it could cause your car to stay in open loop mode, running very crappy and whatnot. id check your thermostat and temp sensor before you went replacing the ecu

Ok well here is the deal I have alredy replaced the CTS and the thermostat, same story, I even made a boost leak tester, nothing. I am trying the get the ECU out but I am having a hard time, I have the center counsel out and the side pannels off, which bolts do I take off for the ECU to come out? I was reading around and I heard that code can be triggard by the upstream O2, do you know if that is true. When I chaged the turbo it came into contact with a small amount of breakleen, but the car worked fine for about the first 30 miles. I don't know. I alredy tried changing the plugs and wires and that did nothing. I replaced the fuel filter just a few hundred miles ago. I think you should also note that when the car is cold and warming up, if you listen to the exhaust you can hear it misfire every once in a while. Please help~!

any thoughts?

I've got an ECU but I might need it for a week. I'll let you know tomorrow hopefully.
 
And yes, any turbo ECU will work. I've used a 97 auto ECU in my 95 manual while my Eprom was being socketed.

Ok I got the ECU out and I can't tell if anything is particularly wrong, the only thing that I really noticed is the metal pieces on teh transistors were a little bubbled and yellow/ crusty. I included some pics of that. Is that normal? or does it matter?


Thumbnail Image



Thumbnail Image



Thumbnail Image



Thumbnail Image



Thumbnail Image

Very possibly that could be fried. Does it have a strong smell?

No, it doesn't which is strange but it is kind of bubbled looking. What do you think? If I just showed a mech. shoudl they be able to tell?

Another thought is this, I was reading on DSM talk and it seems like it is possible for the upstreme O2 sensor to trigger a P0125 code. Can anyone confirm this?

I guess if it was shorting out....

Eff it, it is going back to the mech. Oh well

That ECU doesn't look healthy. I wish I would have save the pics of mine :/

At this point I just don't know, I am taking it to a gauy who is going to hook it up to a computer that will tell him everything the ECU is receiving and then he will know right away if it is bad.

That yellow stuff could possible be harmless flux you can test it out by just scratchign it with ur nails. It shoudl flake off if it is. Also the bubble affect on the transistor is a type of protective conformal coating. Used on electronics that r exposed to moisture, dust and basically the environment. Its all non conductive and scratches off. The coating has a really gloossy look and feels almost like sticky silicone if u run ur hand on it.

It was the upstreme O2, how gay is that? I have now idea how it spit out a P0125 but that was the problem, $270 later. Oh well, now it is fixed!