steffeac

Did a search of threads and found this which seems to keep happening to my 2005 TL w/ 190k miles

https://acurazine.com/forums/3g-tl-p...melted-731045/

So some background, last year around Thanksgiving engine started knocking and running really rough, hooked it up to diagnostic tool and found Ignition Coil for #1 piston (I think, it's the one on the back left if you're facing engine, closest to passenger side) was misfiring. Thinking it's no big deal I go and buy a new ignition coil and 6 new spark plugs. Start replacing spark plugs and when I get to the ignition coil I mentioned (#1 I think), the coil is stuck in the spark plug sleeve/tube. Car wouldn't start so had to have it towed to my mechanic. Long story short, old ignition coil was melted/fused into the spark plug sleeve/tube and he had to basically drill it out. He replaced the old spark plug and installed a new ignition coil.....car runs fine, until this month when engine started running really rough again. Figure it's the same problem, take it back to mechanic and get another new Ignition coil put on due to the same issue, ignition coil is melted/fused to the spark plug sleeve/tube.

Picked car up yesterday, drove it home maybe 20 miles, parked it for like 2 hours then had to run some errands and engine starts running rough and knocking again. Once again it looks like the ignition coil is melted/fused into the spark plug sleeve/tube. Getting really frustrated at this point. My mechanic is at a loss as to why this keeps happening.

I'm wondering if anyone could shed some light on what the problem seems to be before I take it to the dealership and potentially get fed a bunch of crap to get this fixed.

justnspace

iTrader: (1)

ECU maybe water logged and shorting out due to the A/C drain tube or Sunroof drain tube being clogged. Check ECU for evidence of water.
ECU is located in the center stack near passenger footwell

ExcelerateRep

Ignition coils are an electrical component encased in plastic. Either the electrical wiring inside the coil shorted out for some reason and that caused the heat, or the engine was running very hot, in which case other coils should have same melting issue.

It sounds like an isolated failure of electrical components, in this case either the coil, or the spark plug; but Justin does have a very good point about checking the ECU so I'd do that.

It is also possible this issue was caused by engine oil. Was there any on the bottom of the bad coil pack? It is possible for oil to eat through plastic. If this were the case I'd say it worked it's way into the coil and caused a short, which would lead to the burning; or it can just cook and cook inside until it builds up enough pressure and heat to melt the coil (seen it before on a 240sx with a Sr20). If this were to be the case chances are you'll need to replace the coil, valve cover gasket, and the seals for the plugs.

Have you replaced the coil pack connector harness yet? Perhaps your current one is what's giving you the issue, check for exposed wires, frays, ect. Additionally, it never hurts to check your grounds!

steffeac

What's the ECU? Not up on all the acronyms....sorry.

Have a repair manual being delivered to my local AutoZone on Monday so I can understand all this stuff better.

Around the same time the first ignition coil problem arose, my radio also went out completely....no power, sound, or anything. Wondering if the two issues are connected somehow.

Crashmaster

The only other time I have seen this was due to a faulty alternator. The alternator should be putting out about 13.5 to each coil. The coil being a transformer; transforms the 13.5 volts into about 30,000 volts. Well, what happens when you increase the 13.5 to around 16 volts. It also increased the output of the coil and causes them to overheat. I would go back to basics and give the electrical system a good check. Have you done anything to the electrical system? Different battery? Added electrical components? Anything?

steffeac

Only added a new battery last year before this all started happening. Everything else is stock and haven't added anything to the car.

justnspace

iTrader: (1)

ECU = Electronic Control Unit. the BRAINS of your car.

it's a common occurrence, thus why I automatically knew to check ECU for evidence of waterlogging. it creates a short, and damages coil packs

Coby2015

nfnsquared

Yes, all the information is above your post....

justnspace

iTrader: (1)

Coby, read the thread.