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| '87 Fiero 4.0...Engine Suddenly Quit During An Easy, Steady 60 mph Cruise (Page 1/1) |
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Warlordsix
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OCT 11, 08:30 PM
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(BTW the title says 4.0, but I mistyped that and cannot edit it. The engine is a 4.9)
So the other night I'm just cruising south on Rt 1 along the shoreline from Daytona Beach to New Smyrna Beach. Nice night, windows down, steady 60 mph when the engine just died with no warning whatsoever. Bam, nothing. Coasted to shoulder. Wouldn't start. Got a tow home and stuffed her in the garage. The way she died so immediately I suspected Hall effect sensor or pickup coil.
Having no scanner I started by manually confirming she had no spark. Then I tested the coil, which tested good. I was getting ready to test Hall effect when I remembered I happened to have a spare HEI ignition control module sitting on my parts shelf. So I pulled the old ICM out of the distributor, and the first thing I noticed was the PO hadn't used proper thermal paste beneath it. He used lithium grease, which is not correct. Anyhow, I chucked my spare ICM into the distributor, buttoned it up, and the engine started right up. My guess is the lack of thermal paste caused the previous ICM to burn up. What surprised me was the way it failed...no warning, no previous driveability problems, nothing. Has anyone had an ICM die like this?
Looking back over the past few weeks, however, maybe I did have a warning....I run an ALDLDroid to real-time monitor a bunch of engine parameters, including spark advance. A few weeks ago I noticed my spark advance seemed to be erratic and jumping all over the place during steady-state driving. The thing is, I thought spark advance was controlled by the ECM, not the ICM, no?
Ernie
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'87 Fiero 4.9 5-speed[This message has been edited by Warlordsix (edited 10-11-2021).]
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lou_dias
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OCT 13, 09:01 PM
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Raydar
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OCT 13, 09:02 PM
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Doesn't the ICM have a connection to the pickup coil too? Sure the ECM adjusts timing, but it has to have something to start with. I would think that it needs the ICM and the cam (hall effect) sensor.
Did you happen to see the "4.9 expert wanted" thread that fierofool started? They've been chasing an ignition problem with that one, too.
Edit - Sorry. I was babbling, and didn't answer your question.
Yeah, some 2.8s go through ICMs like M&Ms. Especially if they're cheap chinese ones, or are not installed using the correct thermal paste.[This message has been edited by Raydar (edited 10-13-2021).]
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Gall757
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OCT 13, 09:12 PM
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| quote | Originally posted by Warlordsix:
Has anyone had an ICM die like this?
Ernie |
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It happens with the 2.8 all the time.
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Warlordsix
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OCT 13, 09:18 PM
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Yeah, thanks, Lou. I'm all over the Cadillac Forum. Really good stuff there.
Ernie
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'87 Fiero 4.9 5-speed
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Warlordsix
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OCT 13, 09:19 PM
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Thanks, Raydar. I'll have to check back into that thread.
Ernie
| quote | Originally posted by Raydar:
Doesn't the ICM have a connection to the pickup coil too? Sure the ECM adjusts timing, but it has to have something to start with. I would think that it needs the ICM and the cam (hall effect) sensor.
Did you happen to see the "4.9 expert wanted" thread that fierofool started? They've been chasing an ignition problem with that one, too. |
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'87 Fiero 4.9 5-speed
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