Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: rustynail on 21 March 2008, 16:25:56
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Hi all!
Can somone one point me in the direction as to why my omega 2.5 v6 is revving up all on it's own?
I have been having problems with my LPG convertion and had decided the car had to go.
Now today, having decided to trade it in, i went out for a drive looking for her replacement.
The engine was revving quite high and on one occasion after i stopped and turned off the ignition, turned it back on again and it was revving up and down all on it's own!
Any solutions?
Rusty
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what sort of rev range? And have you ensured that the throttle control under bonnet - next to butterflies is not stuck...
Has there been any work done recently that would have unsettled anything in the engine bay?
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Hiya!
Because of my backfire problems using gas, i have had my garage fix the nearside exhust gasket that had a slight leak when cold, and install a new EGR Valve.
To be honest, the car has always had a tendancy to fluctuate it's revs when driving in traffic etc. So much so that i have often said that the car has a mind of it's own!
The work in the Garage still made no odds the my backfires! and have just installed another set of air pipes! I now concider the car a petrol only!
Rev range is from tickover to 2000+rpm
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Check all 'vacuum pipe connections' and I mean 'all', also clean the 'Idle Control Valve' with carb cleaner then WD40.
I had a idle speed problem on my 2.5 (tick-over rpm 500 to 1700)which turned out to be a vacuum pipe connector which had perished and was leaking badly.
regards
richard
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Engine can only rev if its getting air from somewhere, check the throttle stops, the butterflys should close completely, someone may have 'adjusted' the screw at some point.
Are vacuum pipes connected properly?
Is the brake servo vacuum pipe OK...no holes worn in it? is the seal OK in the servo ?
Remove breather assy to check the fancy seal underneath it.
Remove the plennum to check the 6 O rings are intact.
If no luck you will have to remove the inlet manifold and inlet bridge to check the seals and look for anything that could prevent them sealing properly, cracks etc.
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Ah! Looks like I have a busy day tomorrow!
Maybe all this has something to do with my LPG problem as well!
Thanks for your suggestions, all of you, lets hope the rain holds off for the morning!
Rusty
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Sorry to be a pain, but I though it was all sorted!
I Started the car up next day and it was running perfect!
Anyway, I cleaned the throttle assembly and checked the vacuum pipes, but could not find anything untoward.
Used the car this weekend with no trouble. :y
But it happened again today! fluctuating revving, then it would be ok again then revving again.
When I stopped and opened the bonnet could find nothing wrong.
In desperation, and maybe a little temper >:(, I thumped the top of the engine and it stopped revving! all is right with the world again.
Does this point to a direction to solve this problem? :-?
Rusty
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Guess its knowing where to hit it!
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What LPG system do you have? I have a leonardo AEB 175 and I've known it to bring these symptoms up from time to time. It can go months without a problem then suddenly the over-revving appears for a week or so. Does the over-revving only happen on gas or on petrol as well? I never have any idle problems on petrol.
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Hi Rickboy
Because of my LPG problems i am only running on petrol at the moment, but it can happen running on gas too!
I have an older Emmegas system, ( gas is put into the air intake rubber tubes) you know, the one dealers don't want to know about!
It seems to me that it is almost like there is something switching the engine from low to higher revs all on it's own.
Rusty
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ensure that throttle butterflies closing completely - some cowboy lpg'ers open these a little to allow better gas idle...
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Yes, I cleaned these and made sure that they were shutting too! :y
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MIght be worth blanking the egr in case that is sticking open. Basically, air is getting in somewhere.
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Fitted a new EGR valve last week when the Garage done the nearside Exust gasket that was slightly leaking when cold! :-/
I am at a loss now!
Panic! Panic! Panic! 8-)
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MIght be worth blanking the egr in case that is sticking open. Basically, air is getting in somewhere.
Thanks for your previous reply Theboy.
Is it possible then, to run with the EGR blanked off (bear in mind this valve is a new one) and if it is, how do you blank it?
Is there anything under the engine head cover that can course the problem?
Sorry for the what might be obvious, but I'm a Chippy, not a Mechanic!
All replies very gratefully received.
Rusty
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As someone said , its worth removing the breather unit (black plastic thing that has a cover with Ecotec written on it) and checking the seal (oring thingy) underneath.
I'd check all the thin vacuum hoses AND the rubber connectors at the ends (can perish/split).
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Its fine to run with blanked egr - I bit of neatly cut coke can fitted between the egr gasket and the egr itself works well.
Worth checking plenum o-rings, and the other inlet gaskets for leaks.