Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: Sir_Mixalot on 22 July 2006, 18:01:39

Title: Idles high from cold?
Post by: Sir_Mixalot on 22 July 2006, 18:01:39
When i turn on my ommy (2.5), it idles around 1400, over the course of a minute or so this drops down to its usual 4-500 where it will stay until the car is left to cool for a long period.

Why is this? I cleaned out the ICV not so long ago.  Is it an indicator of something I need to do?

Any help appreciated.
Title: Re: Idles high from cold?
Post by: Marks DTM Calib on 22 July 2006, 18:10:22
It should do......most engines do when cold
Title: Re: Idles high from cold?
Post by: Taxi_Driver on 23 July 2006, 07:20:53
As Mark says normal......its called automatic choke.......i remember the days of manual chokes!!  :-?
Title: Re: Idles high from cold?
Post by: summat on 23 July 2006, 09:22:34
Quote
It should do......most engines do when cold

What!, 1400rpm?, not wishing to question the master - I thought cold idle was around 800rpm on a barge?
Title: Re: Idles high from cold?
Post by: TheBoy on 23 July 2006, 09:24:40
My 3.0l MV6 idles at around 1200 - 1400 rpm when starting from cold.  After about a minute, drops back to 600 - 700rpm (if ECC on auto)
Title: Re: Idles high from cold?
Post by: JasonH on 23 July 2006, 09:33:38
My 2.5 does the same as TheBoy's.
Title: Re: Idles high from cold?
Post by: Marks DTM Calib on 23 July 2006, 09:35:14
Of course its not a choke......its simply the ECU running high idle during warm up....
Title: Re: Idles high from cold?
Post by: summat on 23 July 2006, 09:41:14
Hmmm, I *do* remember reading somewhere (probably Over There) that the 800/500rpm was normal, problem is I can't find it now (typical) - whilst my memory is pretty crap I do remember thinking at the time that mine was spot on what was said Over There. Either way, mine idles at a very smooth 800 for first couple of minutes before dropping. 1400rpm?, half the time when you're motoring you'll be at these revs. Off to search for original post.
Title: Re: Idles high from cold?
Post by: TheBoy on 23 July 2006, 09:43:44
Around 500rpm (maybe shade lower) is normal for warm idle with aircon compressor off, 700 rpm about right for warm idle with a/c on...
Title: Re: Idles high from cold?
Post by: Marks DTM Calib on 23 July 2006, 09:45:11
Its more than possible that the 2.6/3.2 idles lower at warm up than the 2.5/3.0 as its a different management system with quite a modified injection setup.....

In fact, it makes sense that it does as it doesn't have air injection etc....
Title: Re: Idles high from cold?
Post by: summat on 23 July 2006, 09:59:36
Ah, a quirk of the F/L's. I'll stop googling for proof I'm not a gibbering lunatic then  :D
Title: Re: Idles high from cold?
Post by: Taxi_Driver on 23 July 2006, 11:12:24
Quote
Of course its not a choke......its simply the ECU running high idle during warm up....

Doesnt the ECU enrich the mixture as well.....for a short period?
Title: Re: Idles high from cold?
Post by: TheBoy on 23 July 2006, 11:14:37
According to my FC, it must be running rich to use that much fuel on cold idle ;)

I think Mark was saying its not like old fashioned auto choke...
Title: Re: Idles high from cold?
Post by: Taxi_Driver on 23 July 2006, 11:35:14
I realise it not like the old fashioned mechanical auto chokes.....and the trouble they caused.....i remember conversion kits being available to convert them back to manual chokes!

I'll call it 'ECU controlled slighty higher revs and slightly richer mixture'  instead then :P
Title: Re: Idles high from cold?
Post by: nixoro on 23 July 2006, 11:53:18
I'm assuming the 2.0 idles sligtly higher mine sits just under 1k revs and when cold goes up slightly and drops after a few minutes to just under the 1k mark again.
Title: Re: Idles high from cold?
Post by: TheBoy on 23 July 2006, 12:16:44
IIRC, 4 pot ones idle at about 750 - 850rpm when warm.
Title: Re: Idles high from cold?
Post by: TheBoy on 23 July 2006, 12:17:31
Quote
I'll call it 'ECU controlled slighty higher revs and slightly richer mixture'  instead then :P
Like you, I'll settle for choke ;)
Title: Re: Idles high from cold?
Post by: Marks DTM Calib on 23 July 2006, 13:29:33
Its normaly refered to a 'cold idle'
Title: Re: Idles high from cold?
Post by: Sir_Mixalot on 24 July 2006, 00:21:21
Thanks for the replies...Was worried it could be down to an air leak that seals itself when the engine warms up and expands.