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Coil Issues

(1999 Toyota Camry)
in Maryville, IL on January 19, 2010
car started misfiring; found bad coil and spark plug; had to retap head, install heliax and new plug; new coil burnt immediately; help please.
Displaying 2 answers & 1 comments
Popular Answer
I have seen the ignition coils fail on these not real often like other car manufactures but often enough. I always use "never seize" on spark plug threads so they are easy to remove next time. One wire at the coil is power with the ignition key turned on or engine running the second wire gets grounded by the ECU/ computer. I suppose the driver in the computer may have failed either shorting out or not triggering the coil but the computers are really reliable on Toyota's. I would look at the wiring I see a lot of rodents chewing on wires or perhaps a wire has shorted out to ground somewhere, need a wiring diagram and a volt/ohm meter to investigate. Autozone have some popular workshop manuals for free on line once you register (for free) on their website is a company that independent auto repair shops "buy" their information from that offer a very reasonable service to do it yourselvers. You get a one year subscription to year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... great quality information same as the professionals have ,much better than generic workshop manuals from parts stores, much cheaper than the factory manual. or try and get an online repair manual subscription.
on January 19, 2010
Spark plugs were change at the dealer between 85-100k miles; although I cannot confirm it, I believe the mechanic used an air wrench to tighten the plugs (overtightened and possibly cracked the threads; over time (approx 3 years), heat cycles and pressure caused the threads to fail); the failed plug came out with the replacement burnt coil; plug threads were distorted and no threads remaining inside the head.
on January 19, 2010
Can you describe what happened to the new coil? And why were the threads damaged?
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