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LC Series 100 ignition mystery challenge...

mediacliff

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Jun 20, 2020
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My beloved 2001 LC has a gremlin. She has 190k miles and still runs and rides like new. But, three long dealership visits and $$$$ later, the gremlin still remains. No one seems to be able to figure out this one. I'm hoping someone here has experienced a similar issue....

1) First issue; Car refused to start in a local GA parking lot. Engine turned, but would not fire. (like key had not been programmed) No "check engine" errors. I went home and retrieved 5 additional keys. Two of the extra keys worked! Now I had four that did not work, and two which worked every time. All worked great with the two working keys... for a week. (Now 500-miles from home in FL.)

2) Second issue; A week later, car refused to start. Engine turned, but would not fire (like key had not been programmed) No "check engine" errors. None of the 3 keys I had with me worked. Towed to dealership in Cocoa Beach FL. Claimed a "few communication error messages" showed in computer.
Cleaned some connectors on relays. Reconnected computer diagnostics and all error messages had disappeared. ALL 3 keys now worked fine... for another three days and 10+ starts.

3) Third issue; Car refused to start. Engine turned, but would not fire. Towed to dealership in Clermont FL. No error codes in computer. Suspected relay issues and cleaned all connectors. They replaced (at my encouragement) the EFI relay. Erased all keys in computer, reprogrammed the 3 keys I had. Tested for 2-days. All worked perfectly and I made it back to GA without issue. They mentioned that I would probably have to reprogram my additional 3-keys when I got home. But, now all 6-keys worked fine without reprogramming.

I took the now-running-fine car to the dealership in Gainesville GA upon returning for a compete diagnostic. No error messages in computer. They kept it for 3-days, testing it each day. It worked perfectly.... for 6-months.

4) Forth issue; Six months and 2000+ miles later, car refused to start. Engine turned, but would not fire. Amazingly, this happened in the same parking lot as the first issue! I went home and retrieved all 5-additional keys. None worked. I went through the key programming sequence in the parking lot with each key. But, none would fire the engine.

Towed to good local mechanic in Clarkesville GA. When the car arrived at his shop and was downloaded from the wrecker, both of the 2-keys I left with the car now worked fine! No error messages or disable codes showed in the computer. When I came to pick up the car, I used a third key to try to start.... now, none of the 3-keys worked.

Suspecting a possible fuel pump issue, they sprayed some starting fluid into the fuel injector... and it tried to start for a second. They then disconnected the fuel line to make sure fuel was getting to the injectors. It was pumping out just fine. Allowed the fuel to dry and reconnected the fuel line. Then, it started fine with the two keys I left with them.

Everyone's is now at a loss. No one suspects the main computer... though I'd happily change it if I thought that was the issue. Why some keys (sometime) work, and others do not indicates some communication problem between the keys and the computer/transponder. It is unclear why they start working again. We thought just accessing the computer in diag mode might be resetting something.

But, during the last issue, just towing the car seemed to have fixed it... at least temporarily. There must be some logic here.... but the clues have yet to lead us there.

Any ideas would be highly appreciated!

Thanks!
Cliff

Thanks!
Cliff
 

karl2000

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What a strange one....

No real ideas I'm afraid..

I did wonder if its maybe a bad wire somewhere (ie broken inside) - or another bad connection. The fact that it worked after being moved (tilted) on and off a breakdown truck might mean an unhappy wire/connection physically moved and became happy again.

But that doesnt really explain why some keys would work and others wouldn't...

Real mystery... I'll watch this thread with interest - good luck!
 

SteveJB

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Wonder if you could drive around with a fault code reader plugged in for a few days and see what if any codes appears tell you what though you got yourself some patience to see it through this amount of time and best of luck finding out what is wrong
 

Jon Wildsmith

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