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Omega Help Area => Omega General Help => Topic started by: bury omega on 29 August 2010, 17:09:31

Title: v6 misbehaves when cold
Post by: bury omega on 29 August 2010, 17:09:31
engine very rough when the engines cold,sounds like some cylinders missing. and brake pedal also intermittently very stiff and unresponsive before cars fully warmed up, as if no assistance.

also air con does not seem to chill properly,but does blow cold air.

not too bothered about air con but suspect vac pipe issues, and I gather that brakes air con and brakes all rely on a vaccum. when I start up I hear a sound behind dash,? sucking. and when I turn it off  with bonnet up.theres a definent hiss from the top of the engine at the back

if I wait till the engines warmed up a bit (generally the time it takes to smoke a cig) car runs okay, the engine and brakes are fine.

its been doing this a while, been to garage who took off pipes to top of engine and cleaned some gunk out of them, and changed oil, in hope that replacing old thick oil might be causing things to stick when cold. does not seem to have helped as yet.   posted similar a while back, suggestions of idle control valve and exhaust manifold. both seem okay. ICV  appartently only a year old.

any suggestions gratefully recieived, thanks.

Title: Re: v6 misbehaves when cold
Post by: Welung666 on 29 August 2010, 17:14:42
Get yourself a tin of carb cleaner preferably with a straw type nozzle. Start it up from cold and give little short squirts around the area where the hissing is coming from. If you squirt on the leak or disconnected pipe then the revs will rise for a second or two. That gives you a better idea of the area to search for split pipes or disconnected pipes :y
Title: Re: v6 misbehaves when cold
Post by: bury omega on 29 August 2010, 17:22:29
Quote
Get yourself a tin of carb cleaner preferably with a straw type nozzle. Start it up from cold and give little short squirts around the area where the hissing is coming from. If you squirt on the leak or disconnected pipe then the revs will rise for a second or two. That gives you a better idea of the area to search for split pipes or disconnected pipes :y

Cheers!- sounds worth a shot! is it safe to be spraying around? i.e. whats my chances of becoming a human fireball?
Title: Re: v6 misbehaves when cold
Post by: Broomies Mate on 29 August 2010, 18:44:58
Quote
Quote
Get yourself a tin of carb cleaner preferably with a straw type nozzle. Start it up from cold and give little short squirts around the area where the hissing is coming from. If you squirt on the leak or disconnected pipe then the revs will rise for a second or two. That gives you a better idea of the area to search for split pipes or disconnected pipes :y

Cheers!- sounds worth a shot! is it safe to be spraying around? i.e. whats my chances of becoming a human fireball?

Carb Cleaner is flammable, so avoid squirting a large amount on the exhaust manifolds (you shouldn't need to spray there anyway), but provided you try this technique with a cold engine, you should be absolutely fine.  :y

EDIT: The brake servo hose is quite a thick one (I think the thickest diameter pipe in that area).  It is also plastic, not rubber.  It comes from the right hand side of the servo and runs along the top of the engine, to a connection on the right hand side of the Plenum.  Check this pipe carefully, and also it's connections both ends.