Hi All,

My 3.0 Elite Auto is misbehaving, She keeps dipping at idle and if you put your foot down, she stutters and tries to impersonate a wallaby. :(

I thought maybe Crankshaft position sensor or possibly a blocked fuel filter?

I've done the paperclip test and the only codes are 12 and 31 which as I understand it are test start and no RPM, both normal.

Is it possible to have a Crankshaft Position Sensor fault without it generating a code?

Also I have the dreaded Abs ECU/speedo problem could that be related in any way?

Or am I off the mark and it sounds like something else?

Cheers

RR

first off give the ICV (Idle Control Valve) a darn good clean, then check for any air leaks  :y

Have you had any work done on it lately?

As said clean ICV first (may need a couple of goes), clean contacts on MAF sensor plug and socket with contact cleaner.  If it still does it try it with MAF sensor disconnected - could be a dodgy sensor.

Thanks Chaps, I'll clean the ICV, and MAF contacts tomorrow, I don't know about recent work as I haven't had the car long.

Will report back once done.

Cheers

RR

I would also check what happens when you unhook the plug to the maf sensor see if it runs better

Right, think I may have found the problem, the small rubber gasket/o ring type thing that goes onto the spigot that runs from the inlet manifold into the vacuum pipes (ecotec plastic bit on top of the inlet manifold) is shredded, you can hear the air leak.

If I put weight on the plastic bit and thus putting more pressure on the join, the tickover smooths out.

Does an air leak into the inlet manifold sound a plausable cause of the stuttering upon acceleration?

Would anyone know the name of the oring/gasket in question so I can get a new one?

Cheers

Jim

That sounds a very likely cause.

If you go to your Vauxhall dealer they will look up on screen the part to order it in for you while you look at the screen.

There are plenty of maintenance guides on the forum including one on cleaning the breathers http://www.omegaowners.com/forum/YaBB.pl?num=1152598350 . that may have the part number of the item on it. In any case that is a bit of recommended maintenance.

varche

Varche wrote on 10. Dec 2009 at 13:50:

That sounds a very likely cause. If you go to your Vauxhall dealer they will look up on screen the part to order it in for you while you look at the screen. There are plenty of maintenance guides on the forum including one on cleaning the breathers http://www.omegaowners.com/forum/YaBB.pl?num=1152598350 . that may have the part number of the item on it. In any case that is a bit of recommended maintenance. varche

Cheers, the part number was on one of the guides, ordered, should be here in a couple of days.

The air leak makes sense as it would be unmetered air causing the mixture to be up the creek.

Cheers

Jim

Success!  Well sort of. I found that the third torx bolt housing on the breather bridge had sheared, so the bridge was not secured, hence air leak past the seal.

I reattached the piece of the housing with superglue and replaced the seal as well.

It is 100 times better than it was, but there is still the occasional blip, It seems to me that the rubber sealing fins on the ICV maybe the cause of the small leak as it just seems too loose a fit in the intake manifold.

Can the rubber section be replaced independently of the ICV itself?

If not what would be the implications of using some form of instant gasket to firm up the seal a bit?

Lastly does anybody have an idea on price for a new breather bridge as I'm not convinced of the longevity of my superglue repair?

Cheers

Jim