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Omega Help Area => Omega General Help => Topic started by: Ewan on 03 May 2012, 11:14:35

Title: pre facelift 3 litre misfire
Post by: Ewan on 03 May 2012, 11:14:35
After a headgasket replacement, car starts and runs OK for a few minutes then starts to misfire. It seems to get progressively worse, until it will barely move off in 1st. There is nothing coming up on the dash about a misfire, but reading through the whole list of possible faults there appears not to be anything relating to misfires anyway. Any suggestions? I can induce a misfire by moving the ignition cables on the righthand side, which stops when I release them. I looked for leaking HT in the dark but couldn't see anything.
Title: Re: pre facelift 3 litre misfire
Post by: tigers_gonads on 03 May 2012, 11:54:50
Pull the Ht leads off the plugs and check for oil in the plug wells.
Title: Re: pre facelift 3 litre misfire
Post by: Ewan on 03 May 2012, 12:00:43
Nope. Nothing there.
Title: Re: pre facelift 3 litre misfire
Post by: tunnie on 03 May 2012, 12:03:38
Sounds like one or more of the HT leads is breaking down. Do you have a code reader? Might be worth updating your profile with your location, as we may have a tech2 near you.

Clear down codes, then get them read and see which cylinders are miss-firing.

Why was head gasket changed? Hope it was not because of mayo on the filler cap!
Title: Re: pre facelift 3 litre misfire
Post by: Ewan on 03 May 2012, 12:23:19
I have done the paperclip test, with the engine running, and nothing relating to misfires has come up. Like I said nothing on the list seems to relate anyway. What code numbers would I be looking for?
The head gaskets were found to have eroded through in a couple of places. The bores were so full of water that they were hydrolocked I know people on this site say that it is extremely rare for head gaskets to go, but believe me, mine had.
Title: Re: pre facelift 3 litre misfire
Post by: Jimbob on 03 May 2012, 12:28:11
the 2.5 and 3.0 engines cant report missfires unfortunately...

that only comes with the 2.2, 2.6 and 3.2
Title: Re: pre facelift 3 litre misfire
Post by: Ewan on 03 May 2012, 12:38:33
Thanks for that. Usefull to know for sure. Thought I might have been unaware of something.
Title: Re: pre facelift 3 litre misfire
Post by: Jimbob on 03 May 2012, 12:40:44
your description certainly sounds like dodgy leads are a fair possibility, especially after being disturbed.

they are connected the correct way and fully pushed home at both the dis and engine ends?
Title: Re: pre facelift 3 litre misfire
Post by: Ewan on 03 May 2012, 12:53:30
Yes, everything is pushed home. But if anything was loose, why should it run OK initially? I don't really buy the HT leads breaking down as there is certainly at least two or three misfiring, and I can't see that happening all of a sudden when there was not a trace of misfiring before.
Title: Re: pre facelift 3 litre misfire
Post by: tigers_gonads on 03 May 2012, 13:05:40
As the leads get warm, the insulation breaks down and you get a missfire
Title: Re: pre facelift 3 litre misfire
Post by: Ewan on 03 May 2012, 13:29:45
But two or maybe three - all of a sudden? But I'll look into it. Certainly it would be a good outcome. It's the knackers yard for the car if I can't sort this out. It has been under a death sentence for a few months now, on sorn but I just can't bring myself to do it. This has been the hardest car that I've ever had to scrap, I like it so much. Those leather seats oooooh.
Title: Re: pre facelift 3 litre misfire
Post by: tigers_gonads on 03 May 2012, 14:43:11
But two or maybe three - all of a sudden? But I'll look into it. Certainly it would be a good outcome. It's the knackers yard for the car if I can't sort this out. It has been under a death sentence for a few months now, on sorn but I just can't bring myself to do it. This has been the hardest car that I've ever had to scrap, I like it so much. Those leather seats oooooh.



Stick a request for a set of Ht leads off one on the breakers on here in the test section.
If you ask admin nicely, they may move it to the bits wanted / for sale section  ;)
Title: Re: pre facelift 3 litre misfire
Post by: tunnie on 03 May 2012, 15:30:11
the 2.5 and 3.0 engines cant report missfires unfortunately...

that only comes with the 2.2, 2.6 and 3.2

D'oh!

Thought they could  :-[
Title: Re: pre facelift 3 litre misfire
Post by: omega3000 on 03 May 2012, 17:05:19
Could be coil pack , similar as mine was doing till i changed it  ;)
Title: Re: pre facelift 3 litre misfire
Post by: spurgindavid on 03 May 2012, 23:04:01
mine was doing this for the last few weeks, not helpful when your trying to drift!
changed the coil pack 20 mins ago and bobs your uncle and fannys your aunt

back to her usual self  ;D
Title: Re: pre facelift 3 litre misfire
Post by: Ewan on 04 May 2012, 10:57:42
Thanks all.