Symptoms of bad electronic spark control module
02-06-2018, 09:36 PM
#1
Drifting
Thread Starter
Symptoms of bad electronic spark control module
1989 stock, auto transmission
this is us not the module in the distributor, but is the module that mounts on the passenger side of the car near the rear of the engine. I think it connects to the knock sensor. Any way to check it to see if it’s ok and working. Still trying to locate cause of misfire and slight and intermittent idle surge. Also does it work in open mode or just closed mode?
this is us not the module in the distributor, but is the module that mounts on the passenger side of the car near the rear of the engine. I think it connects to the knock sensor. Any way to check it to see if it’s ok and working. Still trying to locate cause of misfire and slight and intermittent idle surge. Also does it work in open mode or just closed mode?
02-07-2018, 01:38 PM
#2
Le Mans Master
If you monitor timing with timing light and hit exhaust manifold, watch for timing to retard. If you have a way to monitor data you should see a knock signal to correspond with hitting manifold.
02-07-2018, 01:55 PM
#3
Team Owner
Can you take the module out and have it tested?
02-08-2018, 06:21 PM
#4
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1989 stock, auto transmission
this is us not the module in the distributor, but is the module that mounts on the passenger side of the car near the rear of the engine. I think it connects to the knock sensor. Any way to check it to see if it’s ok and working. Still trying to locate cause of misfire and slight and intermittent idle surge. Also does it work in open mode or just closed mode?
this is us not the module in the distributor, but is the module that mounts on the passenger side of the car near the rear of the engine. I think it connects to the knock sensor. Any way to check it to see if it’s ok and working. Still trying to locate cause of misfire and slight and intermittent idle surge. Also does it work in open mode or just closed mode?
Don't know the details of the '89 ECM calibration, but I suspect that the closed-loop fueling and spark enable conditions could be independent of each other.
I'd look elsewhere to find the driveability problem cause, but if you are able to eliminate the non-ESC items and the problem still exists, and want to test the ESC system on the car, drop me a PM. I've got a plug in harness that will let you monitor the ESC hardware operation while driving down the road. If you strike me as a trustworthy sort, I might be able to be talked into loaning it out.
02-08-2018, 06:28 PM
#5
Team Owner
The ESC module, if faulty, shouldn't be able to cause a misfire or idle surge. It will either do nothing, or merely ask the ECM to delay/retard the spark. The ECM won't eliminate the spark either way.
Don't know the details of the '89 ECM calibration, but I suspect that the closed-loop fueling and spark enable conditions could be independent of each other.
I'd look elsewhere to find the driveability problem cause, but if you are able to eliminate the non-ESC items and the problem still exists, and want to test the ESC system on the car, drop me a PM. I've got a plug in harness that will let you monitor the ESC hardware operation while driving down the road. If you strike me as a trustworthy sort, I might be able to be talked into loaning it out.
Don't know the details of the '89 ECM calibration, but I suspect that the closed-loop fueling and spark enable conditions could be independent of each other.
I'd look elsewhere to find the driveability problem cause, but if you are able to eliminate the non-ESC items and the problem still exists, and want to test the ESC system on the car, drop me a PM. I've got a plug in harness that will let you monitor the ESC hardware operation while driving down the road. If you strike me as a trustworthy sort, I might be able to be talked into loaning it out.
02-08-2018, 07:00 PM
#6
Tech Contributor
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I'm trying to dust the cobwebs off my memory at the moment. In '91 was the ESC board soldered to the memcal?
02-08-2018, 07:02 PM
#7
Team Owner
My co-worker made it for me a hundred years ago, and I recently modified it to also (do development) work on non-ECM C3s. I did ESC work on the LT1/LT4/LT5 and a bunch of the non-fun engines in the nineties. The L98 was before my time in that group.
I'm trying to dust the cobwebs off my memory at the moment. In '91 was the ESC board soldered to the memcal?
I'm trying to dust the cobwebs off my memory at the moment. In '91 was the ESC board soldered to the memcal?
02-08-2018, 07:35 PM
#8
Drifting
Thread Starter
The ESC module, if faulty, shouldn't be able to cause a misfire or idle surge. It will either do nothing, or merely ask the ECM to delay/retard the spark. The ECM won't eliminate the spark either way.
Don't know the details of the '89 ECM calibration, but I suspect that the closed-loop fueling and spark enable conditions could be independent of each other.
I'd look elsewhere to find the driveability problem cause, but if you are able to eliminate the non-ESC items and the problem still exists, and want to test the ESC system on the car, drop me a PM. I've got a plug in harness that will let you monitor the ESC hardware operation while driving down the road. If you strike me as a trustworthy sort, I might be able to be talked into loaning it out.
Don't know the details of the '89 ECM calibration, but I suspect that the closed-loop fueling and spark enable conditions could be independent of each other.
I'd look elsewhere to find the driveability problem cause, but if you are able to eliminate the non-ESC items and the problem still exists, and want to test the ESC system on the car, drop me a PM. I've got a plug in harness that will let you monitor the ESC hardware operation while driving down the road. If you strike me as a trustworthy sort, I might be able to be talked into loaning it out.
02-08-2018, 07:40 PM
#9
Team Owner
I'm not looking at it but I believe you can. There should be a knock retard and a cumulative count. At least there was on my Auto Xray where one counts knock and the other one is cumulative and resets at 128 or something
Last edited by aklim; 02-09-2018 at 12:12 AM.