Help!! I'm at my wits end.
#17
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Join Date: Feb 2010
Location: Atlanta GA metro, OTP North
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It still has symptoms of a failed LH.
Swap it out again, you may have my old one!
Heat sensitivity is not usually tested, try putting a heat gun on the LH to see if it fails when temp is elevated.
This is of course after all other diagnostics/repairs have been done.
Dave
Swap it out again, you may have my old one!
Heat sensitivity is not usually tested, try putting a heat gun on the LH to see if it fails when temp is elevated.
This is of course after all other diagnostics/repairs have been done.
Dave
#18
Man of many SIGs
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Check and clean engine grounds at the back of the Vee,(saw that you did that already) the coil grounds, and remove clean and replace the main engine ground under the car on the passenger side. When the computers find a ground, the car will run great, when they don't find a ground, the engine will shut off just like you turned a key off. The car will crank just fine, but not start until the computer happens to find a ground, then it happens all over again. No rhyme or reason as to when the computer finds that ground.
This problem happened exactly like this on my '89. Cleaned the main engine ground and have not had an issue since.
This problem happened exactly like this on my '89. Cleaned the main engine ground and have not had an issue since.
I would start with the engine idling and the hood open, and poke around with a dowel to try to aggravate the problem. One area to poke would be the cam position hall sensor and its harness. I would also poke around the ISV harness, and knock sensors/harnesses/connectors.
I hate shotgunning... though it probably doesn't hurt to replace the items you've replaced, if you don't know the history of the car, you may be replacing stuff that was replaced not too long ago anyway.
I wonder if a Durametric or Sharktuner could tell more about the "hiccup."
I would also try tapping and shaking things in the CE area and in the connectors for the two ECUs.
The fact that it hiccups quickly, does sound more like an ignition related problem than a fuel related problem, but that still leaves plenty of possibilities.
I hate shotgunning... though it probably doesn't hurt to replace the items you've replaced, if you don't know the history of the car, you may be replacing stuff that was replaced not too long ago anyway.
I wonder if a Durametric or Sharktuner could tell more about the "hiccup."
I would also try tapping and shaking things in the CE area and in the connectors for the two ECUs.
The fact that it hiccups quickly, does sound more like an ignition related problem than a fuel related problem, but that still leaves plenty of possibilities.
The most common cause of this is high resistance in one of the spark plug wires....and this includes the coil wires.
This can be "green corrosion", burned up resistors, burned up ends into the caps, not completely pushed in coil wires at the coil, the wrong coil wires at the coil, and a poor brand of spark plug wires.
ANY spark jump or very high resistance (corrosion) will force the spark to "jump" around the rubber boot and short to the actual coil primary terminals. The car will instantly die, but will restart....exactly like you describe.
There's a supplier of spark plug wires, out there, that has ends that go into the distributor caps that make a 90 degree bend, but the actual wire can pull out of that 90 degree piece. The wire will stay inside the "boot", but will be completely disconnected, allowing a spark jump and "coil flame out".
There's two completely different designs of coil wires that go into the actual coils....and two completely different kinds of coils. (A genuine Beru set of spark plug wires includes both kinds of coil wires.) There is a style that had a "pin" inside the coil (just like at the distributor cap end.) This needs a female style end to connect over that internal pin (just like the connector at the distributor cap end.) The other style is a traditional "American style" coil with a male end that connects to the brass contact inside. Many times we will find the wrong style coil wire at the coil end, which forces a "spark jump" situation.
The other common problem is the plastic rain caps that are on the coils. The coil wire MUST go over the top of the inner edge of these rain caps, in order to make a good connection at the coil. The rubber must go over the top of this plastic by about 4mm. There are poor quality coil wires out there that are too small and will not go over this inner edge....they butt up to the plastic and stop. When this happens, the coil wires are generally not be connected internally and, once again, the spark will have to jump.
This can be "green corrosion", burned up resistors, burned up ends into the caps, not completely pushed in coil wires at the coil, the wrong coil wires at the coil, and a poor brand of spark plug wires.
ANY spark jump or very high resistance (corrosion) will force the spark to "jump" around the rubber boot and short to the actual coil primary terminals. The car will instantly die, but will restart....exactly like you describe.
There's a supplier of spark plug wires, out there, that has ends that go into the distributor caps that make a 90 degree bend, but the actual wire can pull out of that 90 degree piece. The wire will stay inside the "boot", but will be completely disconnected, allowing a spark jump and "coil flame out".
There's two completely different designs of coil wires that go into the actual coils....and two completely different kinds of coils. (A genuine Beru set of spark plug wires includes both kinds of coil wires.) There is a style that had a "pin" inside the coil (just like at the distributor cap end.) This needs a female style end to connect over that internal pin (just like the connector at the distributor cap end.) The other style is a traditional "American style" coil with a male end that connects to the brass contact inside. Many times we will find the wrong style coil wire at the coil end, which forces a "spark jump" situation.
The other common problem is the plastic rain caps that are on the coils. The coil wire MUST go over the top of the inner edge of these rain caps, in order to make a good connection at the coil. The rubber must go over the top of this plastic by about 4mm. There are poor quality coil wires out there that are too small and will not go over this inner edge....they butt up to the plastic and stop. When this happens, the coil wires are generally not be connected internally and, once again, the spark will have to jump.
Thank you very much to all of you for your input. I am currently out of town but I will check these items and report back here once I get back to my car in the next couple of days.
#19
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I agree.
Try removing the CE board cover and the adjacent carpeted cover to allow the LH better cooling and see is that eliminates the problem.
That's how I verified my LH was the issue.
https://rennlist.com/forums/928-foru...ermittent.html
The resolution:
https://rennlist.com/forums/928-foru...l#post11200529
edit - looks like you posted in that thread with this issue back then.
Try removing the CE board cover and the adjacent carpeted cover to allow the LH better cooling and see is that eliminates the problem.
That's how I verified my LH was the issue.
https://rennlist.com/forums/928-foru...ermittent.html
The resolution:
https://rennlist.com/forums/928-foru...l#post11200529
edit - looks like you posted in that thread with this issue back then.
#20
Man of many SIGs
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I agree.
Try removing the CE board cover and the adjacent carpeted cover to allow the LH better cooling and see is that eliminates the problem.
That's how I verified my LH was the issue.
https://rennlist.com/forums/928-foru...ermittent.html
The resolution:
https://rennlist.com/forums/928-foru...l#post11200529
edit - looks like you posted in that thread with this issue back then.
Try removing the CE board cover and the adjacent carpeted cover to allow the LH better cooling and see is that eliminates the problem.
That's how I verified my LH was the issue.
https://rennlist.com/forums/928-foru...ermittent.html
The resolution:
https://rennlist.com/forums/928-foru...l#post11200529
edit - looks like you posted in that thread with this issue back then.
#21
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