Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: REvil71 on 01 January 2008, 20:38:00

Title: Hi, Anyone help on a idling/misfire perhaps...
Post by: REvil71 on 01 January 2008, 20:38:00

I have a 99 pre-face lift elite 2.5 petrol and she is driving me up the wall.
Start her from cold, lovely idles perfect, drive for more than a few yards or let her idle for a little then the miss happens. Sounds like a cylinder has dropped. This has happened out of the blue. Changed leads but no difference. Anyone got any ideas.
Thanks

Title: Re: Hi, Anyone help on a idling/misfire perhaps...
Post by: TheBoy on 01 January 2008, 20:38:52

Is the miss only at idle? If so, look for unmetered air getting in.

Title: Re: Hi, Anyone help on a idling/misfire perhaps...
Post by: REvil71 on 01 January 2008, 20:41:01

From cold idling and a little driving - fine . Once it even thinks about getting warm the fault occurs. Idlies rough and driving feels like a large hesitation as if 1 or more plugs are undone.

Title: Re: Hi, Anyone help on a idling/misfire perhaps...
Post by: TheBoy on 01 January 2008, 20:44:12

Quote

From cold idling and a little driving - fine . Once it even thinks about getting warm the fault occurs. Idlies rough and driving feels like a large hesitation as if 1 or more plugs are undone.

Could be coolant temp sensor, would need a live data feed to know for def

Title: Re: Hi, Anyone help on a idling/misfire perhaps...
Post by: REvil71 on 02 January 2008, 13:21:35

I've just noticed the heater bypass valve isnt plugged into anything. should it be if so what

Title: Re: Hi, Anyone help on a idling/misfire perhaps...
Post by: ians on 02 January 2008, 13:28:28

'isn't plugged in'

- there should be three coolant hoses and a vacuum pipe on top.

But shouldn't affect idling.

Something tells me you're not really talking about the HBV though...

Title: Re: Hi, Anyone help on a idling/misfire perhaps...
Post by: bigdods on 02 January 2008, 15:46:48

Both my old 2.5 and my newer 3.0 suffered odd idling problems and missing/loss of power. In both cases a replacement dis pack was needed.

Title: Re: Hi, Anyone help on a idling/misfire perhaps...
Post by: REvil71 on 02 January 2008, 16:19:25

Is there any test I can do before I replace the dis just incase it isn't that. Also I was talking about the HBV , the water connections are fine but there is no vacuum line connected.

Title: Re: Hi, Anyone help on a idling/misfire perhaps...
Post by: ians on 02 January 2008, 16:24:28

The HBV shouldn't affect idling, but I'm not sure if the vac leak from the disconnected hose might have any consequences..?  

AFAIK the vac pipe should go through the bulkhead somewhere in the vicinity of the coolant hoses.   May well have broken off at the bulkhead?

Anyway I would try removing the idle control valve and giving it a good clean to start with - can't do any harm.

Title: Re: Hi, Anyone help on a idling/misfire perhaps...
Post by: Marks DTM Calib on 02 January 2008, 16:39:12

Any ECU light or fault odes stored.....it is classic over fueling when hot type symptoms which tends towards coolant temp sensor.

Title: Re: Hi, Anyone help on a idling/misfire perhaps...
Post by: REvil71 on 03 January 2008, 15:43:45

Is there a link for the coolant temp sender or pics.
cheers