Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: J_K on 05 August 2008, 22:00:30

Title: Missfire
Post by: J_K on 05 August 2008, 22:00:30
I got my 2.5 V6 today, delighted with it only one small problem with it.

It has a hesitation/missfire at low revs, seems to struggle, I'd say one cyliner isn't firing as its not as smooth as it should be.  Its not as bad when its cooled down a bit.

Most likely cause? Plugs/leads....

I got a set of plugs on my way home this evening, only place was open was halfords so I now have 8 plugs  ::)   How easy/difficult are they to change?  I can see the drivers side bank pretty easily although does the egr (I think??) have to come off, passenger side looks a bit more difficult but I'll get at it somehow...

Plugs and leads are the obvious ones but could it be anything else, it seems to be just affecting a few cylinders though rather than the general running of the car and there's no warning lights up on the dash either which I suppose is a good thing.


Also the metal pipe coming off the egr (I think thats what it is) on the drivers side is very rattely?  Any way of stopping it or is it something that usually happens.

Thanks.  ;)
Title: Re: Missfire
Post by: rickyboy on 05 August 2008, 22:04:21
Does the engine management light come on when you turn the ignition onto position 2 (without starting the car)?
Title: Re: Missfire
Post by: J_K on 05 August 2008, 22:14:31
Er... Yes.....

That and the battery light, handbrake warning and the oil light...

All the rest go out...

I bet I have a problem don't I?.....  Nothing on when its running though.
Title: Re: Missfire
Post by: rickyboy on 05 August 2008, 22:30:29
That's a good thing.  Was suspecting that the bulb had been taken out but it obviously hasn't.  Read "paperclip test" in the maintenance section and give us the codes anyway but it looks like you are looking in the right area.  Ignition system would be the obvious place to start.  Also check for oil in the plug wells.
Title: Re: Missfire
Post by: J_K on 05 August 2008, 22:35:48
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That's a good thing.  Was suspecting that the bulb had been taken out but it obviously hasn't.  Read "paperclip test" in the maintenance section and give us the codes anyway but it looks like you are looking in the right area.  Ignition system would be the obvious place to start.  Also check for oil in the plug wells.

I was thinking thats what you were thinking alright, I went and checked the manual to see if it should be on so no worries there (I'd have never thought of checking that though....

Oil in the plug well's will be done tomorrow along with the spark plugs.
Will try the paper clip test tomorrow too.

Thanks.
Title: Re: Missfire
Post by: philhoward on 05 August 2008, 23:18:12
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That's a good thing.  Was suspecting that the bulb had been taken out but it obviously hasn't.  Read "paperclip test" in the maintenance section and give us the codes anyway but it looks like you are looking in the right area.  Ignition system would be the obvious place to start.  Also check for oil in the plug wells.

I was thinking thats what you were thinking alright, I went and checked the manual to see if it should be on so no worries there (I'd have never thought of checking that though....

Oil in the plug well's will be done tomorrow along with the spark plugs.
Will try the paper clip test tomorrow too.

Thanks.
Just me being me...but first time round this as "i'll oil the plug wells tomorrow"...the idea is there shouldn't be any in there!  If there is, then cam cover gaskets need replacing and breathers cleaning out - standard for V6's, i gather..
Title: Re: Missfire
Post by: J_K on 05 August 2008, 23:32:43
Quote
Quote

Oil in the plug well's will be done tomorrow along with the spark plugs.
Will try the paper clip test tomorrow too.

Thanks.
Just me being me...but first time round this as "i'll oil the plug wells tomorrow"...the idea is there shouldn't be any in there!  If there is, then cam cover gaskets need replacing and breathers cleaning out - standard for V6's, i gather..

Allow me to rephrase that, the plug wells will be checked for oil tomorrow while I'm changing the spark plugs :D  :y
Title: Re: Missfire
Post by: tmx on 06 August 2008, 01:12:57
missfiring ignition faults etc are not recorded by the ecu btw! so if no faults are found then thats why! its usually the dis pack that dies around 100 - 140k is the lifespan of one
Title: Re: Missfire
Post by: J_K on 06 August 2008, 10:00:16
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missfiring ignition faults etc are not recorded by the ecu btw! so if no faults are found then thats why! its usually the dis pack that dies around 100 - 140k is the lifespan of one

And I'm on 124k so that could also be the problem.

I suppose the best thing to do is start from the plugs and work backwards....

Edit: Paperclip test shows up nothing out of the ordinary.
Title: Re: Missfire
Post by: ians on 06 August 2008, 11:36:40
I suggest you follow the breather cleaning guide thoroughly regardless of whether there is oil in the plug wells.  Take the plenum off (good guide for that too) and then change the plugs - access much easier.  (You can also inspect the HBV then for signs of leaks too.)
Title: Re: Missfire
Post by: PaulW on 06 August 2008, 11:51:31
watching this thread with interest, as I'm on the same boat as you...

177k miles, hesitant upto 4krpm then gets full power/stops missing...

replaced coilpack, plugs, leads, checked multirams, done allsorts, but still the same...
Title: Re: Missfire
Post by: J_K on 06 August 2008, 12:04:35
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watching this thread with interest, as I'm on the same boat as you...

177k miles, hesitant upto 4krpm then gets full power/stops missing...

replaced coilpack, plugs, leads, checked multirams, done allsorts, but still the same...

Interesting, mine also seems to be ok at high revs too although I'm not sure what it should be like really....
Title: Re: Missfire
Post by: PaulW on 06 August 2008, 12:06:59
Well my old 2.5 pulled through the entire range (had 113k on the clock when I sold it)

this one, its as flat as a pancake upto 4k, and then goes as it should high revs.
Title: Re: Missfire
Post by: blob on 06 August 2008, 13:02:32
i have got the same problem which is getting worse it is very lumpy when i start up from cold does the dis pack eventuly fail completley? i have 72000 miles on the clock
Title: Re: Missfire
Post by: J_K on 06 August 2008, 14:50:35
Mine seems to get worse as it gets hotter.

Also an awful vibration from it, I can feel the car rocking even when its just ticking over, could it not be firing on all cylinders or would that be more noticable.

Its just confusing me at this stage  :o
Title: Re: Missfire
Post by: jonathanh on 06 August 2008, 15:02:50
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Mine seems to get worse as it gets hotter.

Also an awful vibration from it, I can feel the car rocking even when its just ticking over, could it not be firing on all cylinders or would that be more noticable.

Its just confusing me at this stage  :o

a single cylinder misfiring on a V6 is less noticable than a 4pot (1/6th of the power not 1/4).  V6 should be smooth not rocking

good luck

Title: Re: Missfire
Post by: J_K on 06 August 2008, 15:23:56
I was thinking but unsure.

I know ideally I shouldn't be driving it then but will it do it that much damage if I have to drive it for an hour or two to get somewhere that has tools?
Title: Re: Missfire
Post by: jonathanh on 06 August 2008, 15:29:16
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I was thinking but unsure.

I know ideally I shouldn't be driving it then but will it do it that much damage if I have to drive it for an hour or two to get somewhere that has tools?

i would not be too keen on it.  you run the risk of unburn fuel in the cat which probably is not too good for it
Title: Re: Missfire
Post by: mega3.0v6 on 06 August 2008, 16:06:57
I had a missfire on my 3.0 changed engine temp sensor not the on to the gauge inside the car which has 1 wire with a female connector the one next to it. Missfire has not gone worth a try as it is only a tenner a nd i found this info through autodata which my friend has who owns a garage.