Omega 2.5 missfire HELP!!! - sps
Hi

I would appreciate any help or advise that any of you may be able to give.

I have a Omega 2.5 V6 petrol CD that is miss-firing. I have had the spark plugs changed whilst being away from home on business by an autotune company - they noticed that one of the spark plugs had water on it (this was the only one) obviously, this was the cause of the miss-fire, the car has been fine for the last 1000 miles but then it rained!! I now have the exact same problem and the car is awful, the guy who fitted the sparks said that the head gasket looks o.k. - could it be the HT leads?

Any help or suggestions would be appreciated - I don't want to keep spending money until I can get to the root of the problem.



Regards


SPS
Omega 2.5 missfire HELP!!! - johnmac
Apparrently it only takes a pin-hole in the spark plug Ht lead before 'arcing' will occur. You could try putting some grease over the boots see if that helps. If so its most likely them. The other thing is oil coming in fom the valve cover.
Omega 2.5 missfire HELP!!! - Chad.R
SPS,

There have been many cases of Omega V6's miss-firing due to faulty HT leads reported on this forum and it seems to be a common problem - what's the age of the car?

I'd start by checking the HT leads, though they can be a pig to remove and refit - you may have to remove the wipers and the panel in front of the windscreen etc to gain access as they route from the back of the engine block.

I had the HT leads changed on my V6 Omega (94) about 10 months ago while the cam cover gaskets were being done, though I wasn't experiencing any miss-fires it was probably only a matter of time -(8yrs/95K)

Vx dealers quoted £75+vat per set (you need 1 for each bank of cyl), Autovaux (01924 376003) did both for around £90 inc.

Good luck.
Chad.
Omega 2.5 missfire HELP!!! - Aprilia
Very common fault.
Change plug leads (use genuine Vauxhall ONLY). Also check the coils for damage/deterioration.
Omega 2.5 missfire HELP!!! - sps
Many thanks for all the helpful replies - Aprilia, why do you say use Vauxhall only? I have seen other postings recommending autovaux as alternatives at half the price of Vauxhall. Just interested.

SPS
Omega 2.5 missfire HELP!!! - Dynamic Dave
Autovaux supply genuine Vauxhall parts, but a do so a lot cheaper.
www.autovaux.co.uk
Omega 2.5 missfire HELP!!! - Aprilia
Omega management ECU monitors the HT voltage waveform (by looking at the 'reflected' voltage waveform in the coil primaries). HT leads must therefore have exactly the right impedance (i.e. be OEM) otherwise ECU will log a fault. There may be aftermarket leads that are 'spot on', but you would be taking a chance.
Omega 2.5 missfire HELP!!! - Chad.R
Aprilla,

Omega management ECU monitors the HT voltage waveform (by looking at the 'reflected' voltage waveform in the coil primaries). HT leads must therefore have exactly the right impedance (i.e. be OEM) otherwise ECU will log a fault.

Just out of curiosity, when the ECU logs a fault as described above - what is the result/how is the driver informed?

Chad.R
Omega 2.5 missfire HELP!!! - BodgeJob
For the record replaced mine after rodent damage @ 71K miles (must have been hungry!) with CDC Electraspark leads (OEK608) purchased from Sutton Auto Factors www.autospares-group.com/index.htm at a cost of £44.77 inc VAT. Whilst not as substantial as the OEM fitment manufactured by BERU www.beru.com/english/home/ have been fine in the 9 months (10K miles) since fitted. Certainly not had any indication of ECU fault logging. However as fitting is a complete swine (DIS module is nearly impossible to reach even with the induction hardware removed) OEM is probaly sensible if only to avoid the risk of having to do it again (though one wonders if they fail regularly just how good the OEM leads are!).

Jon L.

By putting the Web URL inside brackets stops them becoming clickable links. I\'ve amended. DD.
Omega 2.5 missfire HELP!!! - Aprilia
I suspect most aftermarket leads are now OK. A few years back they were not very accurately impedance matched to OEM. This led the ECU to believe that one of the plugs had gone down and it shut off the relevant injector (to protect the cat.).
 

Value my car