psycho_vince

My car is pretty much stock, it ran fine before I fucked w/ the ECU. All I did was desolder the original prom chip and solder in a socket in its place, then placed the OE chip that I desoldered in it to make sure everything was good. I put it back in the car and it started fine. The only issue I had was that it wouldnt idle down from like 2500 rpm. I found it kinda odd, but it ran fine other than that. I figured it was my IAC. Then I shut the car off and try to start it again, then I get solid CEL, no fuel pump prime, LED doesnt light on ECU. I take it back apart, everything looked good, didnt touch anything and put it back in. Then it starts and runs fine again, I even shut it off a few times and it started back up no problem, except that it still doesnt idle down. Then it does it again, solid CEL. I tried jiggling the chip in the socket, thinking it was loose, but it didnt do anything. WTF did I do wrong? Could the OE chip have become corrupt from the desoldering heat? Im about 85% confident in my soldering job (can post pics) it looks identical to the P28 I have sitting next to it (well the soldering quality I mean). Im pretty sure my connections are good where I soldered everything in, none of the board looks damaged from what I can tell, and im out of guesses. I dont think anything with the wiring in the car itself, or mechanical because it ran fine 3 hours ago, then i did my thing and now this. Did I do the chipping process right (for OBD0 you just desolder the OE chip and put a socket in right?)? Anyone help? BTW this is my first ECU chipping Ive done myself, but I practiced on an old video card, desoldering all kinds of ---- on it, putting it back together, and threw it in a PC and it worked, so Im fairly confident that I did ok. ANY help is appreciated. Thanks.

leed

What kind of socket are you using? Machine hole, wipe, or ZIFF?
Are the pins on the OEM chip a little crooked?

My first guess would be shitty chip to socket contact. (if your using a dual-wipe socket and crooked pins on the chip)
2nd guess would be the solder job of the socket or a broken trace that is still touching, but causes intermittent problems.

An easy test for the above is to go KOEO, (assuming you are able to get normal operation w/o a solid cel) then gently apply pressure to the chip and wiggle it side to side. If it CELs with a light touch, time to fire up the iron again.

Also, if you are using dual-wipe sockets, there is a very good chance that is the problem. From personal exp., I can assure you they are piles of ----.

psycho_vince

It kinda works now...90%...

Well, I took the ECU out, and checked the soldering, everything looked good, but I went over it again. I think I got a little better flow on one or 2 contacts, but it seemed to have done the trick...for the most part. I am using a dual wipe socket, and I do see that it sucks (I have a ZIF in my P2 but im not too concerned about that.

Anyway, it starts and runs, everything seems fine, but it still wont idle down. I didnt touch anything between before and after modifying the ECU, and now it doesnt idle down from 3000 rpm. It seems to want to idle down after it warms up a little, it gently bounces from 2500 to 1200 rpm. It sounds like an IAC but it worked fine yesterday before I chipped the ECU. Is there anything else I could be missing? Could the chip have gone bad? Where do I find a stock A6 map to burn onto a blank chip? I went through some bin libraries and didnt find any stock maps. Am I fucked now? Great...

Thanks for the responses, its helped so far, just need to figure out the rest of my issues. And also how to use my chip burner

kenneyd

The same thing happened to me, I just went over the soldering again, and all good.

psycho_vince

Figured it out, had NOTHING to do with anything I, or you guys ever thought about...

There are two large 'thingies' (yes thats the technical term, lol) that attatch to the ECU case off the circuit board that use the case as a heatsink. Well, there was an insulating/heat transfer pad between the case and the 'thingies' and it fell out and I didnt notice. This was causing them to ground out on the case, throwing off the regulated 5V signal (I think thats what happened). When the ECU was plugged in but not bolted to the car, it would run fine but wouldnt idle and all the 5V signals were off kilter. Then I thought that the ECU grounds itself through the case to regulate the 5V signals (sounded feasable in my head). So I bolt it into the car, and then it would get solid CEL. I started to think if the 5V signals had anything to do with it grounding out completely when bolted in, so I started to look for shorts between the case and what I soldered. Didnt find anything, so I took the case off and just had the board plugged in, set on the carpet and started it. It ran perfect, idled down, 5V signals on the money and everthing. So now I was looking for a short between the case and the board, which pointed me to the heat sink area of the 'thingies'. Looking at the other side, I noticed insulating/heat transfer pads on all of them but one... Found the pad, put it back in, and all problems gone. My conclusion was that the 'thingie' fucked me over this whole time. Something that simple and stupid. Oh well, I learned something, and hopefully this will help someone else out if they didnt pay 120% attention to taking it apart. Now I just need to learn to use my datalogging cable and figure out why I cant burn chips...lol. :1

THANKS FOR ALL THE HELP!!! It gave me ---- to look for, and found the problem indirectly, but found it nonetheless. I dont know what Id do without you guys. One more step closer to my car not sucking as much...