Cold running issues
30 March 2009, 07:17 PM
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Cold running issues
Hi,i have had cold running issues for a while now,and it is really starting to p**s me off,car is an MY98 uk turbo with coil pack in centre of inlet manifold,reading up on here,i have changed the maf,water temp sensor,lambda sensor,but it has not made any difference.
The symptoms are as follows,when starting the car from cold,it fires up fine,and idles fine,but when in transit,there is a hesitation untill car has wamed up.
I have only changed the maf this weekend,which has improved things a little,before the maf change,car would start and idle fine,but when in transit up to 3000 rpm would be fine,anything beyond that and engine check light would flash briefly,and car would be very hesitant,again once warmed up,would be fine.
The car has an apexi ecu,the next thing i was going to look at was spark plugs,but tonight i pulled off each ht lead in turn to see if it was sparking ok.Three of them were fine but one was very weak.See picture below
Can anyone shed any light on this,could the coil pack be knackered ?
The symptoms are as follows,when starting the car from cold,it fires up fine,and idles fine,but when in transit,there is a hesitation untill car has wamed up.
I have only changed the maf this weekend,which has improved things a little,before the maf change,car would start and idle fine,but when in transit up to 3000 rpm would be fine,anything beyond that and engine check light would flash briefly,and car would be very hesitant,again once warmed up,would be fine.
The car has an apexi ecu,the next thing i was going to look at was spark plugs,but tonight i pulled off each ht lead in turn to see if it was sparking ok.Three of them were fine but one was very weak.See picture below
Can anyone shed any light on this,could the coil pack be knackered ?
30 March 2009, 08:18 PM
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scarey how often somwone posts the same isue as I'm having...
poor running till water temp reaches 50 degrees approx (apexi ECU too with commander)
I tried adjusting teh ignition and injection to see if it would make any difference
it did: it was better with more fuelling at cold temps (via the water temperature screeen adjust)
anyway, it still didnt get it fully sorted, but today ...it was back to running fine when cold!
no idea what the problem is, but until today it been <5 degrees outside temperature ....today it was 7 degrees
curious...but I aint gonna dwell on it!
poor running till water temp reaches 50 degrees approx (apexi ECU too with commander)
I tried adjusting teh ignition and injection to see if it would make any difference
it did: it was better with more fuelling at cold temps (via the water temperature screeen adjust)
anyway, it still didnt get it fully sorted, but today ...it was back to running fine when cold!
no idea what the problem is, but until today it been <5 degrees outside temperature ....today it was 7 degrees
curious...but I aint gonna dwell on it!
31 March 2009, 07:49 AM
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Hi,i have had cold running issues for a while now,and it is really starting to p**s me off,car is an MY98 uk turbo with coil pack in centre of inlet manifold,reading up on here,i have changed the maf,water temp sensor,lambda sensor,but it has not made any difference.
The symptoms are as follows,when starting the car from cold,it fires up fine,and idles fine,but when in transit,there is a hesitation untill car has wamed up.
I have only changed the maf this weekend,which has improved things a little,before the maf change,car would start and idle fine,but when in transit up to 3000 rpm would be fine,anything beyond that and engine check light would flash briefly,and car would be very hesitant,again once warmed up,would be fine.
The car has an apexi ecu,the next thing i was going to look at was spark plugs,but tonight i pulled off each ht lead in turn to see if it was sparking ok.Three of them were fine but one was very weak.See picture below
Can anyone shed any light on this,could the coil pack be knackered ?
The symptoms are as follows,when starting the car from cold,it fires up fine,and idles fine,but when in transit,there is a hesitation untill car has wamed up.
I have only changed the maf this weekend,which has improved things a little,before the maf change,car would start and idle fine,but when in transit up to 3000 rpm would be fine,anything beyond that and engine check light would flash briefly,and car would be very hesitant,again once warmed up,would be fine.
The car has an apexi ecu,the next thing i was going to look at was spark plugs,but tonight i pulled off each ht lead in turn to see if it was sparking ok.Three of them were fine but one was very weak.See picture below
Can anyone shed any light on this,could the coil pack be knackered ?
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07 April 2009, 09:58 PM
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According to the service manual there are two physical coils and two inputs from the ECU - one is shared by cyls 1 & 2, and the other by 3 & 4. (Check around page 178 of the service manual .pdf - google "1997-1998_impreza.pdf" if you don't already have it).
That suggests to me it's unlikely you have a fault with the coil pack itself, the ignitor (transistor module) or the ECU if it's just one weak spark out of four - I'd replace the HT leads first. Try swapping a couple of them round, that'll soon tell you if one of them is faulty.
That suggests to me it's unlikely you have a fault with the coil pack itself, the ignitor (transistor module) or the ECU if it's just one weak spark out of four - I'd replace the HT leads first. Try swapping a couple of them round, that'll soon tell you if one of them is faulty.
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