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Mechanical Advice Please.

Surfside

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I've owned a VZ commodore for 5 years now. Recently whilst overtaking a truck on a highway my car backfired and triggered off a Power Train fault on the computer.
I've had this problem before and it's either been a spark plug/leads or coil issue.
I've recently moved state so I couldn't use the same reliable, trusted mechanic i've used for years.
I dropped my car off in the morning to a new mechanic and received a phone call that afternoon with him telling me that there was a miss fire in cylinder 1 and that a 'surge' of unknown cause, went through the car's electrical system causing considerable damage.
I drove down in my other car and he showed me a spark plug with the top blown off and a ignition coil shrivelled and melted (never seen anything like it)......it blew out crank shaft sensor and blew out and destroyed my computer.
I ended up with a bill of $2950....excluding the cost of the computer as I sourced it.
What I thought would be a simple changed of plugs/leads or ignition coil....turned into a major cluster ****....
Has anyone heard of anything like this? What could create such energy to do so much damage to a spark plug and coil and the electrics? Did he **** something up?? He couldnt give me an answer.....
 

immortality

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Something shorted in the coil/ignitor sending extremely high voltage back to the computer. It happened to me on an older V6, coil shorted out internally and took out the ignition module. Not sure how it exploded the spark plug though?
 

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Sounds like he [the mechanic] broke the spark plug while removing it, to make it look a worse than what it is,
That's an old trick I heard of back in the 70's.

Did you get a second opinion before going ahead with the repairs ?
 

Trevor loves holden.

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Was it like that when you dropped it off, If you drove it there then how called the computer be stuffed, And if the crank case sensor was destroyed how did you drive it there, sounds like he may of done something wrong..
 

Surfside

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Sounds like he [the mechanic] broke the spark plug while removing it, to make it look a worse than what it is,
That's an old trick I heard of back in the 70's.

Did you get a second opinion before going ahead with the repairs ?
Thanks for the reply.....no I didn't get a second opinion.
Sounds like he [the mechanic] broke the spark plug while removing it, to make it look a worse than what it is,
That's an old trick I heard of back in the 70's.

Did you get a second opinion before going ahead with the repairs ?
Thank you for your reply.
The spark plug looked burnt rather than snapped off. Couldn't get a second opinion as the car wouldn't start after surge went through to drive it elsewhere for someone to look at it..When I arrived at the workshop he had my battery sitting on the floor dead from him trying to get the car started. He had another battery mounted in the car which he also ran flat.
 
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Surfside

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The car was running a bit rough as it was as it wasn't firing on all cylinders. I had to get RACQ to start it up as it sat in my garage for a month and I didn't want to flatten the battery. But the guy got it going after a few minutes, he also said it was just a plug/lead problem or coil from what he could see. Like I said it ran rough but idled ok and I drove it down to the mechanic.
 

Surfside

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Something shorted in the coil/ignitor sending extremely high voltage back to the computer. It happened to me on an older V6, coil shorted out internally and took out the ignition module. Not sure how it exploded the spark plug though?
Thanks for the reply.
The mechanic wrote in his report that he researched the problem and found that it was a 'very' common problem in VZ commodores....thats why I posted the thread as I never heard of it.
I had also taken my car initially to another mechanic a 6 weeks before he did a computer diagnostics on it and found that cylinder 1 was miss firing...he thought it was a fuel line issue.....it cleared the fault and ran well for a few weeks then the powertrain fault tripped out again....so I garaged the car for a month using my other car before taking it to the second mechanic.
 
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Trevor loves holden.

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VZ where a lemon just like the first VE, what ever happened well that's in the hands of the gods, main thing now its been fixed.
 

Daniel Souza

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Thanks for the reply.
The mechanic wrote in his report that he researched the problem and found that it was a 'very' common problem in VZ commodores....thats why I posted the thread as I never heard of it.
I had also taken my car initially to another mechanic a 6 weeks before he did a computer diagnostics on it and found that cylinder 1 was miss firing...he thought it was a fuel line issue.....it cleared the fault and ran well for a few weeks then the powertrain fault tripped out again....so I garaged the car for a month using my other car before taking it to the second mechanic.
When the issue happened the first time , I would have swapped
cyl. 1 spark plug with cyl.2
cyl. 1 lead with cyl 3
Cyl 1 coil with cyl. 4

Those are usually very easy things to do.
The ideal would be also swapping cyl injector with cylinder 5

In this way you could rule out lots of things at once if the issue happens on cyl 1 again or pin point the cause if the issue happened on other cylinder.

Note that I don’t know your engine and swapping leads around is not always possible.
 
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