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[shyboy]

After being over the moon with my new acquisition for a couple of weeks I've hit my first problem.
I was driving in rain this evening when the EML began flashing on and off for about 30 secs., accompanying a persistent misfire, which sounds like one cylinder out. The EML then stayed on for the rest of the journey and the misfire didn't clear, but it didn't seem to have any noticeable effect on MPG per the display or on the idle RPM, but I put the latter down to 6 cylinders rather than 4. I nursed it home although I couldn't have done otherwise as she didn't want to accelerate enough to get me out of 4th gear. I don't think it was in limp mode but I've never experienced this.
I'm going to check/replace plugs as a first step, but haven't worked on a V6 let alone a plug per coil set-up.
Could anyone give me a brief run down on how to proceed with CPP removal, please? How can I check which one is not firing.
I would normally have done the preliminary investigation before asking but need to get the car mobile ASAP and hope I might be able to save a little time with the help of the experts on here. And I don't want to miss the North West meet on Sunday!    
Many thanks in anticipation.
Bill.

[Martin_1962]

I had that with plugs, if you turned off then on it runs fine

[Kevin Wood]

There is a howto on plug removal on the CPP engines, IIRC. Basically you need to remove the 2 screws holding the CPP module to the cylinder head and get a larger pair of bolts to screw into the brass housings under the bolt heads. Then pull on these evenly to break the seal. Remove the connector to the rear of the CPP module and lif it away to reveal the plugs. Driver's side can be removed withoiut disturbing anything esle, IIRC. Passenger side is a bit more of a challenge. You need to shift the air con hose and bracket and loosen the cable tray that runs across the top of that bank.

I believe a flashing emissions light indicates a fault which could damage a cat so best not to run it until it's sorted.

Kevin

[shyboy]

Thanks for your replies. I suppose it's either plug related or a sticky injector?
It has actually started OK this morning with no misfire or EML showing. Thanks for the info.
Just hope I haven't already damaged a cat.  :-/

[Kevin Wood]

My money's probably on a plug. Do you know when they were last changed?

Also, if there's any oil sitting in the plug wells when you take off the coil packs, you need to change the cam cover gaskets and clean out the breathers

Kevin

[shyboy]

Thanks KW. I don't know when the plugs were changed, despite several receipts for full service, so this is on the list of 'belt and braces' work I'm going to do ASAP, including cambelt kit and cam cover gaskets etc. When you say 'break the seal' on the CPP unit, I presume you mean simply to pull it off the plugs.
If only there were 48 hours in a day!
Thanks for your interest.

[Kevin Wood]

Plugs are specified to be changed at 80k on the 2.6 / 3.2, which is a long time. Could be that they haven't been changed but I wouldn't be surprised if some don't last the distance. They're not too expensive from Vauxhall.

An yes, just pull upwards on the coil packs. They have a rubber seal around the edge that can take a bit of a pull to release.

Kevin

[Marks DTM Calib]

Plugs are specified to be changed at 80k on the 2.6 / 3.2, which is a long time. Could be that they haven't been changed but I wouldn't be surprised if some don't last the distance. They're not too expensive from Vauxhall.

An yes, just pull upwards on the coil packs. They have a rubber seal around the edge that can take a bit of a pull to release.

Kevin

Ow, they have no problem lasting the distance....but they have a habit of working loose.

[shyboy]

Thanks fellas. I've definitely got an intermittent misfire.
Plugs working loose! I've never had that before, but if you mean actually loosening in their seatings, then it could possibly be a contributory factor to the blue smoke I experience just on starting in the morning, if there is oil in the plug recesses, although I would have expected poor running at an earlier stage if there was a loss of compression.
I'll post a result when I've done the work out of interest.
Thanks again.

[shyboy]

I've managed to make a start on the plugs today.
On removing the CPP unit on the offside I found the plug recesses completely clean and free of any oil, but of course the luck didn't last. When I removed the nearside unit, (what a struggle), all three rubber covers stayed attached to the plugs, revealing the 'springs' which carry the juice to the plugs. I recovered the covers with pliers and refitted them to the CPP and all seems fine and undamaged, although they are nowhere near as tight a fit as on the other side, which are very tightly fixed. All three recesses were oily, and the front one was full to the top of the plug with water. There was also a small amount of 'mayonnaise' in the plug recesses, (not present on the filler cap or dipstick), and it seems clear that all this is the cause of the misfire.
Is the presence of water unusual, or is it a product of the oil leaking through the gasket and the mayonnaise forming process? Could it have got in from somewhere else? There is no water loss from the coolant header tank and the engine has been running spot on until the intermittent misfire started.
Do you think replacing the camcover gaskets will effect the required cure for the water as well as the oil, or do I need to look for another fault?
I'd really appreciate the experts' comments before I go further.

[TheBoy]

If you have access to a code reader, see what it says. It may not be related to HT. If it is, it will tell you which cylinder is missing...

[ffcgary1]

Water in the plug wells is not un- heard of but will be the cause of the miss fire. clear the water and do the cam cover gaskets, treat it to a set of new plugs and poss leads and your v6 will be like new again. 8-) the mayo may be just the oil seep from the gaskets and the water ingress so that should cure when you do the work.

[shyboy]

Thanks FFCGARY1.
No leads to worry about on a 2.6l but I'm doing the gaskets and have new plugs to fit.
In view of your comments I'll complete this work and hope it does the trick.
Many thanks.

[shyboy]

I'm still in the middle of this job, (business goes mad at this time of the year). I took a much closer look at the CPP unit when cleaning everything up and find that two of mountings for the rubber covers are actually cracked and there are what I interpret as tracking lines running from these. This has got to be the cause of the misfire, but I'm wondering whether something like Araldite might effect a non-conducting seal and a repair if I can squeeze some into the cracks. Anyone think this might work, or is it too much of a long shot? Is there a proprietary material designed for such a job.
God knows how the cracks have been caused. The unit must have been 'ripped' out on a previous occasion I suppose, or used as a football in a workshop.
I'm just going to ring for a price for a replacement, which might make the above job a waste of effort.

[Kevin Wood]

I have found from bitter experience that araldite is not a good insulator

I'm trying to think what might do a better job...

I would be tempted to clean it all up and try it. Clean up around the cracks as best you can and give it a good coating of "damp start". They may well be tracking spark energy away but equally it could be that they'll cause no problems without a plug well full of oil. It's not a difficult part to replace if that fix doesn't work and at 80 quid or so a side, the coil modules are a bit dear...

Kevin