What are the symptoms ?...............

[megsy]

What are the symptoms when a a coil on a GQ EFI petrol motor starts to "play up" ? (early stages).

Thanks.

[growler2058]

Mmmm I thought coils either worked or they didn't?????


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[mudnut]

Sometimes they play up when they heat up.

[Clunk]

Sometimes the play up when they heat up.

do you mean as in engine cutting out????

[mudnut]

I haven't experienced that, but I have had a couple of coils miss badly as they got up to operating temp. Can you get hold of another one to try and see if the coil is the problem?

[threedogs]

Yeah and not working lol
Is it when they get hot they can fail ??

[mudnut]

An old bush mechanic trick was to place the coil in a coke can filled with water. Sometimes the condenser breaks down. Is there any cracks in the insulation of the coil? I suppose We should ask Megsy what the engine is doing to make him suspect the coil?

[megsy]

Thanks for the replies guys....................The question is a continuation of my earlier post about the rough idling.......I've had everything done in the workshop that is recomended by the forum and research on the internet (except the coil)....eg. new plugs, distributor,leads,rotor,head worked on by a specialist,........virtually everything other than the coil....COST SO FAR $3,000.00
It has improved dramatically, but it still seems to miss intermittently when idling at 600rpm.....if I hold my hand close to the tail pipe I can feel it and it makes a sound......wait for it.....phftt.....phftt phftt.

[mudnut]

In my workshop manual, missing at idle could be caused by. Spark plug gaps wrong, short circuit in coil, sticking or faulty emissions system, clogged fuel filter, vacuum leaks, incorrect idle speed (may need to up it to 650 or 700), incorrect timing, low or uneven cylinder pressure and clogged or dirty fuel injectors.

[Cuppa]

Strewth! If it's cost you 3 grand up to now, the extra cost of a new coil is peanuts & worst outcome is that you have a spare coil.

[mudnut]

If it turns out to be the coil, or something as simple as upping the revs, what the hell was his mechanic doing?

[mudnut]

I suppose to add something constructive, have you got time to work through some of the easier things to check, at the moment, Megsy?

[Parksy]

The noise you mentioned coming from the exhaust is a classic case of vacuum leak or an ignition fault. I replaced alot of components on my gq including new injectors, but still had a strange miss at idle. Turned out it was a vacuum leak from the intake gasket. Might not be that gasket in your case, but I found this by spraying inox on the mating surfaces and seeing if there was a change in rpm( engine running while doing this). If you can disconnect one spark plug lead at a time, a change in engine performance would indicate this isn't the problem.

[megsy]

Thanks for that mudnut......new NGK plugs...gap double checked.....tossed out the Champion plugs which had only done 5000km.
Vacum lines all checked.......idle speed is what is has been for the last 17 years (600rpm).....
I am now going to follow your and Cuppa's sound advice....new coil,plus what you listed mudnut ie. check emissions system, new fuel filter.

[megsy]

I'm in the dark with the modern engines.....I was ok with my LANDROVER SERIES 2A (it was like a meccano set)....I could lift the transfer case and gear box out with my 2 hands.

[megsy]

mudnut, I change garages like I change my socks........almost everytime work has been carried out I find a fault in the workmanship.
The worst was when I had a pre-trip service (I did 6000km on the trip) including new front wheel bearings.......they were running as hot as hell.....when I had them checked, the mechanic showed me that the "locking washers" on both front wheels had NOT BEEN TABBED OVER!!!!!

[mudnut]

Get your 25 posts up and download the workshop manuals. You need to find a mechanic you can trust. I had an excellent local but the poor bugger retired due to ill health. I haven't found another one yet, so I do as much as I can, but I even make the odd mistake. It's called the "Human Factor."