Rough idle when engine is cold

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lancia58
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Rough idle when engine is cold

Post by lancia58 »

Hi

When switching on the engine after couple of days that I haven’t drive my car, the idle is a bit rough ( rarely it’s really rough like one plug is not firing ) . After one to two minutes when the engine warms up a bit the idle becomes smooth. Does anybody has an idea what can be the cause for that ?

P.S. I changed the idle stepper motor 2000 miles ago , to a new one due to unstable idle and sudden engine cut off. With the new stepper motor the engine never cuts off again and when the engine warms up the idle is stable and smooth. I renewed the plugs 500 miles ago


Thanks
Zohar
Xantia 2.0 16V Automatic make year 2000 LHD
Citroen C4 THP Automatic make year 2009 LHD
Citroen C4 VTS 2.0 16V make year 2006 LHD
Peter.N.
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Re: Rough idle when engine is cold

Post by Peter.N. »

Car, engine?
lancia58
(Donor 2022)
Posts: 711
Joined: 30 Nov 2010, 07:02
Location: Israel
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Citroen C4 VTS 2.0 16V make year 2006 LHD
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Re: Rough idle when engine is cold

Post by lancia58 »

Xantia SX automatic 2.0 16v make year 2000

Thanks
Zohar
Xantia 2.0 16V Automatic make year 2000 LHD
Citroen C4 THP Automatic make year 2009 LHD
Citroen C4 VTS 2.0 16V make year 2006 LHD
lancia58
(Donor 2022)
Posts: 711
Joined: 30 Nov 2010, 07:02
Location: Israel
My Cars: Xantia 2.0 16V Automatic make year 2000 LHD
Citroen C4 THP Automatic make year 2009 LHD
Citroen C4 VTS 2.0 16V make year 2006 LHD
x 8

Re: Rough idle when engine is cold

Post by lancia58 »

Anyone has an idea ?

Thanks
Zohar
Xantia 2.0 16V Automatic make year 2000 LHD
Citroen C4 THP Automatic make year 2009 LHD
Citroen C4 VTS 2.0 16V make year 2006 LHD
Peter.N.
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Joined: 02 Apr 2005, 16:11
Location: Charmouth,Dorset
My Cars: Currently:

C5 X7 VTR + Satnav Hdi estate Silver
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In the past: 3, CX td Safaris and about 7, XM td estates. Lovely cars.
x 1199

Re: Rough idle when engine is cold

Post by Peter.N. »

As I have only run diesels for the last 25 years or so and the last petrol engines I worked on had a carburetter and distributer my knowledge of modern petrol engines is scant to say the least but, if it sounds as though its missing on one cylinder it probably is, they now apparantly use coil packs, one for each cylinder so I would think that one is faulty, probably getting damp when the car has been standing and the insulation is breaking down until it dries out, you need to be able to disconnect them one at a time until you find the one that makes no difference - that will be it.

Peter
addo
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Post by addo »

Zohar's car has two coils with waste spark, you can read the dwell times or spark advance on Lexia and instantly see if there is a problem.
Peter.N.
Moderating Team
Posts: 11563
Joined: 02 Apr 2005, 16:11
Location: Charmouth,Dorset
My Cars: Currently:

C5 X7 VTR + Satnav Hdi estate Silver
C5 X7 VTR + Hdi Estate 2008 Red

In the past: 3, CX td Safaris and about 7, XM td estates. Lovely cars.
x 1199

Re: Rough idle when engine is cold

Post by Peter.N. »

I told you I didn't know anything about them :?
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