Melted coil - crank no start
06-05-2019, 07:21 PM
#1
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Melted coil - crank no start
Hi There,
I'm working on my sister's 2004 TL w/ auto trans. She was driving and the engine started misfiring. She took it to a shop and they replaced a couple coils that were melted.
Later that day, after turning the AC back on, the car started misfiring again. That's where we are now.
The top of the back, passenger side coil broke off and the rest is stuck in the tube. Of course it's in the back....
Also, I'm not getting any spark or signal to the coil.
I assumed the PCM would be wet from the clogged AC drain tube I've read about, but I took it out and it looked pristine. It's been a while since this happened, so I guess it could've dried, but I don't see any evidence of moisture.
So:
How do I get the coil out? Has anyone experienced this? Do I have to pull the valve cover?
How do I diagnose the spark? Test the Crank and Cam sensors? I haven't been able to find info on the best way to test these sensors.
Thanks in advance for your help.
Duncan
I'm working on my sister's 2004 TL w/ auto trans. She was driving and the engine started misfiring. She took it to a shop and they replaced a couple coils that were melted.
Later that day, after turning the AC back on, the car started misfiring again. That's where we are now.
The top of the back, passenger side coil broke off and the rest is stuck in the tube. Of course it's in the back....
Also, I'm not getting any spark or signal to the coil.
I assumed the PCM would be wet from the clogged AC drain tube I've read about, but I took it out and it looked pristine. It's been a while since this happened, so I guess it could've dried, but I don't see any evidence of moisture.
So:
How do I get the coil out? Has anyone experienced this? Do I have to pull the valve cover?
How do I diagnose the spark? Test the Crank and Cam sensors? I haven't been able to find info on the best way to test these sensors.
Thanks in advance for your help.
Duncan
06-06-2019, 05:40 AM
#2
Happens quite a lot, most times from loose plug. I'd say pull the head and go from there.
I didn't read the following, but maybe some info:
https://acurazine.com/forums/3g-tl-p...melted-731045/
https://acurazine.com/forums/3g-tl-p...inions-959788/
https://acurazine.com/forums/2g-tl-p...inside-813196/
I didn't read the following, but maybe some info:
https://acurazine.com/forums/3g-tl-p...melted-731045/
https://acurazine.com/forums/3g-tl-p...inions-959788/
https://acurazine.com/forums/2g-tl-p...inside-813196/
06-06-2019, 11:53 AM
#3
Race Director
OP, with multiple melted coils, my guess is that the ECU is indeed fried. The coils do get melted from loose plugs, but I've never heard of 3 loose plugs.
Did the shop check the plugs for proper torque when they replaced those 2 coils?
Someone else had the same issue (coil broke off in rear tube) and then got it out IIRC. Do a search and maybe you can find the thread.
I'd definitely remove the strut brace bar if you haven't already. If you have an inspection cam, use that to get a good look into the tube. You might be able to see it with a cell phone camera, dunno. Try using a curve pick to pull it out?
Anyhow, good luck! Keep us updated.
Did the shop check the plugs for proper torque when they replaced those 2 coils?
Someone else had the same issue (coil broke off in rear tube) and then got it out IIRC. Do a search and maybe you can find the thread.
I'd definitely remove the strut brace bar if you haven't already. If you have an inspection cam, use that to get a good look into the tube. You might be able to see it with a cell phone camera, dunno. Try using a curve pick to pull it out?
Anyhow, good luck! Keep us updated.
06-07-2019, 02:28 AM
#4
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Thanks for the replies. It's in there really good. I guess I just have to start digging. It broke off flush with the tube, so there's a lot in there. Too bad it's not on the front...
It's only one melted coil right now, before it was 2. Because I'm getting no spark, I also think it's a bad ECU but is there a checklist to rule out other possibilities? Crank sensor or cam sensor? I can't find good info on testing those.
What do I need to look for in a used ECU? For programming, would i need to tow the car to a shop or dealer?
Thanks again,
Duncan
It's only one melted coil right now, before it was 2. Because I'm getting no spark, I also think it's a bad ECU but is there a checklist to rule out other possibilities? Crank sensor or cam sensor? I can't find good info on testing those.
What do I need to look for in a used ECU? For programming, would i need to tow the car to a shop or dealer?
Thanks again,
Duncan
06-07-2019, 07:30 PM
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I pulled the valve cover. That thing is really in there. The other coils on the back side look like they have swelled some, but they came out alright.
Can I pull the spark plug tube without taking the plug out first? It sure doesn't feel like that's possible.
What do you think about drilling a hole through it? Might be able to twist it and get it loose?
I really don't want to pull the head.
Let me know what you think. Still wondering about testing ECU and how to program a junkyard one.
Thanks,
Duncan
Can I pull the spark plug tube without taking the plug out first? It sure doesn't feel like that's possible.
What do you think about drilling a hole through it? Might be able to twist it and get it loose?
I really don't want to pull the head.
Let me know what you think. Still wondering about testing ECU and how to program a junkyard one.
Thanks,
Duncan
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