ECM Problems

[TURBO 6]

My friend has an 86 GN with a freshly rebuilt engine (100 mi) that I am trying to get running right. My problem is that with the stock AC Delco chip the car does not want to idle until it warms up then after it's warmed up it idles ok but falls on it's face when when you give it gas. Another thing is at aorund 2500 rpm's with no load on the engine it sounds like a rod is knocking. Now I have a spare Hypertech chip which I have no idea what it's set up for, I borrowed it to see if it would help. With this chip the engine runs and idles smooth at any temerature but the check engine light flashes constantly. The fan dosen't come on and the A/C dosen't work, but here's the puzzling part: the knock stops. At the same rpm with the Delco chip it sounds like a rod knocking but with the Hyptertech chip it dosen't do it. WTF? Also it seems that the car is trying to build boost at idle with the Hypertech but not with the Delco. Any help would be apreciated.

 

[bruce]

try setting the IAC, and TPS.
Are you really sure you got the Cam sensor right?, and no vac leaks?.

 

[TURBO 6]

Sorry, Bruce it's way more than that. Cam sensor is right on the money, no vacuum leaks either. The IAC and the tps may need a little attention, but the IAC is pretty much dead on. How do you explain the knocking? Remeber it dosen't do it with one chip but it does it with another. I even went as far as putting the car in diagnostic mode to check the trouble codes. With the Delco chip I got a 44 and a 51. With the Hypertech I cant even get into diagnostic mode. Remember, whith the Hypertech chip in the check engine light blinks constantly. I even tried swaping the ECM with the one from my car, but I get the same probems as with the original ECM. I am leaning more toward a problem with the chips themselves since I get a "PROM Error" code (51) but I can't say for sure. Keep the answers comming, all tries are greatly appreciated.

 

[azgn]

when the SES light flashes, usually the chip/ecm is bad and you are running in batch/limp mode

 

[bruce]

Originally posted by TURBO 6
Sorry, Bruce it's way more than that. Cam sensor is right on the money, no vacuum leaks either. The IAC and the tps may need a little attention, but the IAC is pretty much dead on. How do you explain the knocking? Remeber it dosen't do it with one chip but it does it with another. I even went as far as putting the car in diagnostic mode to check the trouble codes. With the Delco chip I got a 44 and a 51. With the Hypertech I cant even get into diagnostic mode. Remember, whith the Hypertech chip in the check engine light blinks constantly. I even tried swaping the ECM with the one from my car, but I get the same probems as with the original ECM. I am leaning more toward a problem with the chips themselves since I get a "PROM Error" code (51) but I can't say for sure. Keep the answers comming, all tries are greatly appreciated.

A vac leak can explain the knock.
If the same problems persist with a different ecm then the ecm isn't bad, or you managed to get two ecms with exactly the same problem.
44 is lean,
51 is prom.
constant flashing SES with just the one chip would indicate that chip is junk.
You do any welding on the car?, serious lightning while the chips were out of the car, do you store the chips in conductive foam, static electricity?. Did you have the proms out of the holders, and possibly get them in backwards.
I'll still go with a mechanical problem, in addition to a/some prom problems.
If you used the other ecm with the same proms then you didn't rule them out.
Try your prom/ecm to see if it's better.

 

[TURBO 6]

Sorry, Bruce it's way more than that. Cam sensor is right on the money, no vacuum leaks either. The IAC and the tps may need a little attention, but the IAC is pretty much dead on. How do you explain the knocking? Remeber it dosen't do it with one chip but it does it with another. I even went as far as putting the car in diagnostic mode to check the trouble codes. With the Delco chip I got a 44 and a 51. With the Hypertech I cant even get into diagnostic mode. Remember, whith the Hypertech chip in the check engine light blinks constantly. I even tried swaping the ECM with the one from my car, but I get the same probems as with the original ECM. I am leaning more toward a problem with the chips themselves since I get a "PROM Error" code (51) but I can't say for sure. Keep the answers comming, all tries are greatly appreciated.

 

[TURBO 6]

I wonder why that post showed up again? OK, now the chip is changed to a ATR and all the problems went away.
Now for the knock, it happens after 2000 rpm and goes away with a load on the engine. What could this be? This motor is hardly broken in. If you rev it while it's in park it will sound like knock after about 2100 rpm's. Put it in gear and powerbrake it to 2500 rpm's and there is no noise. Any ideas? Thanks for the replies.