Print

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

[Clouseau]

Bit of a weird one, this.

My 2000 Omega CD (X20 XEV) has just passed the MOT and looks good for another year, but it has recently developed a problem when starting from cold.

The engine fires instantaneously but runs rough, as if it was only firing on three cylinders?  After 15 seconds or so and a few blips of the throttle it settles down and then runs perfectly.

I have done all the usual checks, cleaned breathers etc and have also put in a new set of GM plugs. I did find oil in the spark plug well of no. 3 cylinder, but put this down to the rocker cover gasket which has now been replaced with a £25 GM one (!) The oil leak has now gone but the same rough starting problem is still there. No fault codes / EML light either.

Anyone come across this or have any ideas?? :-/

[tunnie]

whats your coolant level like? Is that dropping?

[Abiton]

Have you still got the old sparkplugs that you've replaced?  They may tell a story if you have a look.

What can happen when oil gets in the plugwells is that 'tracking' can occur, which is basically leakage of the spark from the centre contact (top end, not inside engine bit), down over the outside of the ceramic insulator to ground.  This typically leaves a black line of carbon vertically down the outside of the insulator, which is the 'witness' mark made up of cooked engine oil and other crud.

Even with new plugs, if there's a matching line of this crud on the inside surface of the rubber boot at the end of the HT lead, you may still suffer trouble under 'difficult' combustion conditions like cold-start or sudden increase in load ( e.g. pulling away from standstill).  Can probably be cleaned off carefully if this has occurred.

As Tunnie suggests though, another reason for rough running for a short while from cold-start is that there is coolant in one of the cylinders.  This rapidly evaporates or just gets pumped out of the exhaust ports, so resolves quickly. It will get worse though, if this is what is happening, and new headgasket is the only solution.
Not unheard of in high-mileage, less-than-wonderfully-serviced Omega engines. 

[Clouseau]

The old plugs have already been binned, but I'll keep an eye on the new one.  I've got a replacement set of HT leads in the post from ebay (99p including the DIS pack, which you can't grumble at) so will swap these anyway.

The head gasket was replaced 14 months ago when a snapped exhaust stud (then a snapped extractor) meant the head had to come off. The mileage is 105K so I'd be a bit miffed if the new gasket has gone.

I'll keep a close eye on the coolant level though. Might even be worth whipping the spark plug out when it's cold and seeing if there's any coolant in there.

[Clouseau]

Apart from checking coolant levels are there any other symptoms that might point to the HG - (oil is clear and no signs of emulsifying)
?

[cem_devecioglu]

if you are thinking of hg , a compression test when engine is cold may give some answers  imho..

[tunnie]

lots of white smoke on start up, miss fire on startup, smell of petrol in expansion tank.

Check the condition of the dis pack