Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Shaun wild]

I have a 2003 omega estate 2.6V6. After a short while of the car driving perfectly well, the engine fault light comes on and it starts misfiring. I've noticed this occurs at around 85 on the temperature gauge each time I drive it. I've had a probe plugged in and it indicates misfire unidentified cylinder, misfire cylinder 2, misfire cylinder 4. I've ordered new plugs, not delivered/fitted yet but I'm not convinced this will fix it. The confusing factor for me is it only happening once up to running temperature. All help appreciated

[Entwood]

I have a 2003 omega estate 2.6V6. After a short while of the car driving perfectly well, the engine fault light comes on and it starts misfiring. I've noticed this occurs at around 85 on the temperature gauge each time I drive it. I've had a probe plugged in and it indicates misfire unidentified cylinder, misfire cylinder 2, misfire cylinder 4. I've ordered new plugs, not delivered/fitted yet but I'm not convinced this will fix it. The confusing factor for me is it only happening once up to running temperature. All help appreciated

2.6 uses a "coil pack" that "sits" in the cylinder head .. it is possible that as this gets hot it is failing. They do corrode, especially if water leaks from the skuttle onto the 2-4-6 bank - although it is usually the no 6 pot that suffers most. Might be worth taking the coil pack out and looking for either water ingress into the plug wells, or oil in the plug wells ... which means the breather system has not been maintained correctly and you need new cam cover gaskets and a breather clean. Given the faults are on the one side my guess will be a coil pack problem, linked to some other problem .. oil or water

[Shaun wild]

Cheers Entwood, that was my next change, the plugs are my first, cheaper port if call

[05omegav6]

Cheers Entwood, that was my next change, the plugs are my first, cheaper port if call

Makes sense...Removing to check, might as well replace... But your issue will be either the coil pack(s) or the loom. Money is on the coil pack... If it's rusty, remove the foam from the scuttle and reseal it as per the guide... If it's oily then you're into cam covers and breather cleaning.

All well documented here

If you're unlucky, the coil pack will be rust and oil free... In which case you're into the loom. Known good second hand will suffice if required

[polilara]

I have a 2003 omega estate 2.6V6. After a short while of the car driving perfectly well, the engine fault light comes on and it starts misfiring. I've noticed this occurs at around 85 on the temperature gauge each time I drive it. I've had a probe plugged in and it indicates misfire unidentified cylinder, misfire cylinder 2, misfire cylinder 4. I've ordered new plugs, not delivered/fitted yet but I'm not convinced this will fix it. The confusing factor for me is it only happening once up to running temperature. All help appreciated

2.6 uses a "coil pack" that "sits" in the cylinder head .. it is possible that as this gets hot it is failing. They do corrode, especially if water leaks from the skuttle onto the 2-4-6 bank - although it is usually the no 6 pot that suffers most. Might be worth taking the coil pack out and looking for either water ingress into the plug wells, or oil in the plug wells ... which means the breather system has not been maintained correctly and you need new cam cover gaskets and a breather clean. Given the faults are on the one side my guess will be a coil pack problem, linked to some other problem .. oil or water

I had recently syl no 6 plug well full of water due to the leak from the scuttle but for some reason error code indicating misfire in syl no 4. Very bad in idling but in normal driving ok. Today I have all wells dry but still misfire in syl no 4 when idling. Next step perhaps for me is to change coil back bor bank 2.

[shyboy]

If the coil pack is in bad condition, (cracked,rusted,etc.), it might be worth trying to repair using Araldite to re-seal cracks etc. after a careful clean up.
I did this on my 2.6l estate some years ago and to my amazement it worked and hasn't misbehaved since. The debate at the time was whether Araldite conducted electricity or not but whilst I still can't answer that categorically, it did the job.
Worth experimenting before buying a new coil pack?

[05omegav6]

If the coil pack is in bad condition, (cracked,rusted,etc.), it might be worth trying to repair using Araldite to re-seal cracks etc. after a careful clean up.
I did this on my 2.6l estate some years ago and to my amazement it worked and hasn't misbehaved since. The debate at the time was whether Araldite conducted electricity or not but whilst I still can't answer that categorically, it did the job.
Worth experimenting before buying a new coil pack?

Interesting suggestion...

Two concerns...

1. The exposed metal rusts due to condensation due to water ingress from the scuttle, so sealing it in makes sense. But the only reason it is exposed is because it's a multilayer heatshield. When it corrodes it expands this is bad for the plastic because...

2. The plastic goes brittle with heat and is quite thin where the heatsink vents are. So as the heatsink corrodes and expands, splitting the thin, weak plastic... Cracking itself isn't an issue, it the corrosion which causes the cracking in the first place that is the problem... the worse the cracking, then the worse the corrosion was to cause it.

Most epoxy materials soften with heat, some actually return to liquid as low as 60°C, so I would question their suitability for the purpose suggested. Best approach imho would be to reseal the scuttle as per the guide, remove the foam from the bulkhead above the 246 coilpack plug/dispack and renew the coilpack/dispack with a Bosch or GM item.

[shyboy]

I take your points HKT, and I did it very much 'tongue in cheek'. It definitely worked OK, so perhaps I was lucky, (or just made of genius material). 

[Shaun wild]

All sorted, I ordered new plugs then set about gettingat them, what a pain on cylinders 2,4,6 because if the loom. I removed the coil pack to find all 3 plug wells full of mainly water!
I cleaned them out and gave the coil pack a good clean and found the rubbers that protect the plugtops and springs to have split I ordered acoil pack refurbish kit which includes new rubbers and springs. Replaced them, replaced the removed parts and the car is running sweet again. I'm hoping the water got in between the engine and the coil pack seal. But time will tell.
Thanks for all your advice

[05omegav6]

Re seal the scuttle as per the guide... Otherwise the issue will return in short order