Electronic Spark Module
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Instructor
Joined: May 2011
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From: Miramar Florida
Electronic Spark Module
Can someone confirm the location of the electronic spark module on an '86. Is it likely that this has gone bad and causing the engine to hunt during idle. Have already done IAC & TPS setups. What is the likelyhood of this being bad.
Le Mans Master
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From: Clearwater Florida
...... On my '87 its on the pass side looking right at you just inside the fender in front of the HVAC stuff ......... Its very unlikely that it would affect your hunting idle issue since it mainly receives the signal from the knock sensor and adjusts the spark advance ( retard ) accordingly ... any loose exhaust stuff or A/C brackets that might be clanking at idle ?? ..... 'Sides if its pulling timing that is the best indicator that its doing its job ........ look for vacuum leaks , fuel pressure , base timing , and air fuel ratio related items ... the IAC is likely working ( hunting idle ) ...
Thread Starter
Instructor
Joined: May 2011
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From: Miramar Florida
... any loose exhaust stuff or A/C brackets that might be clanking at idle ?? ..... 'Sides if its pulling timing that is the best indicator that its doing its job ........ look for vacuum leaks , fuel pressure , base timing , and air fuel ratio related items ... the IAC is likely working ( hunting idle ) ...
Race Director
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From: Anaheim CA
The ECM tests the knock sensor and ESC module when you start the car, so you will see a Code 43 if there is a problem there. If you don't have a Code 43 then they are probably OK.
You can test for knock retard problems by unplugging the ESC module. You will set a Code 43 and you won't have any knock protection so no WOT runs allowed. If you see a difference in the way the car runs then the ESC might be your problem.
If the ESC is retarding the timing at idle you should be able to see that with a timing light.
The two connectors in the smog pump area are for the A.I.R. divert solenoid and the A.I.R. switch solenoid.
You can test for knock retard problems by unplugging the ESC module. You will set a Code 43 and you won't have any knock protection so no WOT runs allowed. If you see a difference in the way the car runs then the ESC might be your problem.
If the ESC is retarding the timing at idle you should be able to see that with a timing light.
The two connectors in the smog pump area are for the A.I.R. divert solenoid and the A.I.R. switch solenoid.
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From: Miramar Florida
When I set the timing, I unplug that connector at the firewall near the brake booster, and adjusted the timing to 6*. After I'm done, I reconnect the connector, and reset the code by disconnecting the battery. When I run the engine and try to see the timing with the connector plugged, it is so far off that I don't see the timing mark at all on the balancer. Should the timing retard itself that much?
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Instructor
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From: Miramar Florida
How much timing retard is normal when engine is running correctly? When I unplugged the ESM, I saw NO difference in the way the engine ran. Will this be the case if everything is working correctly?
Last edited by Bredd1; Nov 23, 2011 at 04:43 AM. Reason: Typo
Race Director
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From: Anaheim CA
When the EST connector is connected, the timing mark will be up above the timing tab attached to the timing chain cover. It will be about an inch or so above the tab, which might be hard to see, depending on how visible your timing mark is.
When my harmonic balancer went bad several years ago (the outer ring came loose and rubbed a hole in the timing chain cover), I filled the groove of the new one with white enamel. It's very visible for me.
When my harmonic balancer went bad several years ago (the outer ring came loose and rubbed a hole in the timing chain cover), I filled the groove of the new one with white enamel. It's very visible for me.
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Instructor
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From: Miramar Florida
Yes, I've made the timing mark visible with white paint. I edieted my previous post. It now reads that I saw NO change in the engine when I unplugged the ESM. My question is, should I see a difference when its unplugged & does the knock sensor continuously monitors and the motor adjusts or is it only at start-up?
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Team Owner
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From: Summerland B.C. Canada
When I set the timing, I unplug that connector at the firewall near the brake booster, and adjusted the timing to 6*. After I'm done, I reconnect the connector, and reset the code by disconnecting the battery. When I run the engine and try to see the timing with the connector plugged, it is so far off that I don't see the timing mark at all on the balancer. Should the timing retard itself that much?
Race Director
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From: Anaheim CA
The ECM adds about 20 degrees of timing at idle in open loop mode for a total of 26 degrees. The exact amount depends on the coolant temperature.
To test the knock sensor and ESC module, the ECM adds 20 MORE degrees of timing, which will cause the engine to knock while cranking (maybe just as it starts -- I'm not sure on this. It seems to me that the extra advance would cause the engine to kick back during cranking, so it's probably just as it starts). When the ECM detects 2 knock counts it removes the extra 20 degrees of timing. If the ECM does NOT see those knock counts it will set error code 43. It will also set a code 43 if the knock pulses are too wide, which means the ESC module is bad. About 1/2 the time I can hear the knocks just as the engine starts. They make a rattling noise.
To test the knock sensor and ESC module, the ECM adds 20 MORE degrees of timing, which will cause the engine to knock while cranking (maybe just as it starts -- I'm not sure on this. It seems to me that the extra advance would cause the engine to kick back during cranking, so it's probably just as it starts). When the ECM detects 2 knock counts it removes the extra 20 degrees of timing. If the ECM does NOT see those knock counts it will set error code 43. It will also set a code 43 if the knock pulses are too wide, which means the ESC module is bad. About 1/2 the time I can hear the knocks just as the engine starts. They make a rattling noise.
Thread Starter
Instructor
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From: Miramar Florida
I found a spark control module on Ebay, bought & installed it. It didn't improve anything. My other question still stands, does the SCM continuously monitor for knock or just at start-up?
Team Owner
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From: Summerland B.C. Canada
The ECM tests the system at start up.
Your not throwing a code 43, so you might want to look elsewhere for you problem.
