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[AetO]

Had a problem with our Omega a month or so ago. Didn't fire on all cylinders, smelled sulphur etc. Turned out to be (only) a faulty ignition cable.

Changed all six cables (not original Opel parts) and suddenly it had problem starting. Never an issue before. But, it drove smoothly like a dream.

Gradually, the last week, it's been deteriorating again. Still hard to start, takes two or three goes, worse when cold (we have -10 C here now). Misfiring when driving, especially low revs. A bit better above 2000 revs perhaps, and slightly better warm than cold.

Checked and changed spark plugs. No change.
Checked fault codes, no codes showing.

We've had suggestions that it might be the ignition coil that at fault. Any other ideas?

[neilr]

Any water or oil in plug wells. Get mirror and check to see if dispack (coil ) is damp or has rust staining on it. Finally are all plug leads attached firmly to coil. Last but a wild card is the crank sensor breaking down. This doesnt always give codes.

[zirk]

Had a problem with our Omega a month or so ago. Didn't fire on all cylinders, smelled sulphur etc. Turned out to be (only) a faulty ignition cable.

Changed all six cables (not original Opel parts) and suddenly it had problem starting. Never an issue before. But, it drove smoothly like a dream.

Gradually, the last week, it's been deteriorating again. Still hard to start, takes two or three goes, worse when cold (we have -10 C here now). Misfiring when driving, especially low revs. A bit better above 2000 revs perhaps, and slightly better warm than cold.

Checked and changed spark plugs. No change.
Checked fault codes, no codes showing.

We've had suggestions that it might be the ignition coil that at fault. Any other ideas?

Assuming no oil around the spark plug wells, my money would be on the coil pack, dont rule out the leads again or aswell.

Chris.

[AetO]

Had oil in plug wells before we changed them all. None now.

Husband says impossible to check coil pack (is this the same thing as ignition coil - am Swedish, not completely proficient in English car terms) rust in situ, has now ordered new replacement.

Husband also says all plugs definitely sparks.

Any ideas why it's difficult starting now after cable change? Husband, again, adamant all cables well attached.

[Varche]

Had oil in plug wells before we changed them all. None now.

Husband says impossible to check coil pack (is this the same thing as ignition coil - am Swedish, not completely proficient in English car terms) rust in situ, has now ordered new replacement.

Husband also says all plugs definitely sparks.

Any ideas why it's difficult starting now after cable change? Husband, again, adamant all cables well attached.

Hi AetO -welcome to the forum.

1. Had oil in plug wells before we changed them all. None now This is a classic problem with the V6 engine. The oil comes from the cam cover gaskets failing usually associated with inadaquate cleaning of the breathers. If it hasn't been fixed it needs doing. Use only genuine Opel gaskets and "goo". There is a how to in the guides section of the forum.

2. Coil Pack is the same as DIS pack (distributorless Ignition system) or ignition coil. Be aware that there are several variants of the same item depending on the age of the vehicle. The main difference being the wiring loom connector shape - rectangular or oval. If the Bosch part number is the same you will be OK.

Finally have a look under the bonnet with the engine running in the dark. It maybe another ignition spark  plug lead (you call it cable) that is failing. You may  see arcing.

[Marc Taylor]

I had exactly the same prob on my 2.0.  I have just had to change the plugs, leads and rocker cover gasket for the second time in 7 months, it was the leads at fault but changed plugs too

[SteveS]

AetO,
The recommendation on the cam cover seals given by Varche is sound. I tried some copy parts and I didn't even get to see if they would seal as they wouldn't even fit. I then got some Vx ones and no problems for the last 2 years.

However, in my experience oil in the plug wells didn't have any effect on running and there was no mis-fire in that condition. That doesn't necessarily mean it can't cause a mis-fire.

I have had a DIS pack failure and it was only running on 5 cylinders. Someone told me that it must have only been running on 4 cylinders as there are 3 coils each feeding 2 cylinders on the V6. It didn't seem that rough though and maybe it was a failure of the connection between the coil and just one terminal.

Only recently I had an intermittent misfire that was worse at low revs and acceleration. At high revs or steady load it was running on 6. I couldn't find any problems but then it started mis-firing all the time and I tracked it to an HT lead. I replaced the lead and it fixed the regular mis-fire and the intermittent mis-fire as well. All I can think of was the HT was failing and was causing a weak spark. Fine except when the engine was under load. Then the lead failed completely making it easier to find.

Don't rule out spark plugs or HT leads just because they are recently replaced). You may get a spark, but is it the same strength on all plugs?

 

[AetO]

SteveS,
I've heard before that copy seals are no good. Someone said Saab will fit and are better, but I wouldn't know. Or that may have been only the actual covers.

My feeling has been all along that there's something amiss with the new HT leads. Copy parts, mind you from well-reputed shop here in Sweden, Mekonomen. But apparently a few of the leads were a lot longer than original parts. Could that cause start-up problems and/or misfire under load? From what you're saying that seems likely to me.

[SteveS]

AetO,
I have only experience of the one set of seals that didn't fit. Others may be OK, but it is more likely that the VX one will do the job.
Copy parts are generally made to a cost and materials may not be up to the job. The originals will be designed to last several years as they are fitted to the new engines and if they didn't last Vx would gave a major warranty problem. If copy parts only last a year or so I doubt there would be any comeback on the manufacturer.

I always have suspicion over new parts if there is a problem after fitting them. I remember fitting some Champion spark plugs to a mini many years ago. When I had a misfire I suspected I had got something wrong in re assembly of the the distributor cap or something with the HT leads which I had also worked on. I finally found one of the new spark plugs wasn't sparking right. Could be similar with your HT leads.

All through the intermittent misfire and when it was running on 5 cylinders mine always started OK, but the Omega in my experience has always started brilliantly.

[AetO]

Have now fitted new dispack, and voilà! Starts without problems, no misfires, smooth and lovely again!

Took 1,5 hours to replace. With the aid of a small telescope mirror and two different extensions, no need for dismantling much at all. Left the wipers and scuttle in place, only removed plenum and two vacuum hoses.

According to husband, not a good idea to do this straight after a heavy meal though, as you have to practically lie on top of the engine throughout...

[sandune]

Great! Well done. Result!!!!!!!!