Rough Idle-Cold only /2002 S60
#1
Rough Idle-Cold only /2002 S60
This happens upon initial startup in the AM, and smooths out after engine warmup. It seems to be amplified between 1100-1200 rpm.
Simultaneously, when the key is first turned (without cranking), there is alot of 'clicking' coming from the engine compartment. I don't know if the two are related.
The ECT sensor seemed to be an obvious choice, and a test in hot water did identify an unstable pattern when cold. Replacing this did not help the trouble.
I found a split vacuum line and replaced it-no change in status. All vacuum lines seem to be in good condition.
Autozone identified an upstream O2 code. I replaced this sensor, even though O2 is closed loop operation.
From here, the IAT seems like a good choice, though it has not thrown a code.
Any ideas appreciated!
Simultaneously, when the key is first turned (without cranking), there is alot of 'clicking' coming from the engine compartment. I don't know if the two are related.
The ECT sensor seemed to be an obvious choice, and a test in hot water did identify an unstable pattern when cold. Replacing this did not help the trouble.
I found a split vacuum line and replaced it-no change in status. All vacuum lines seem to be in good condition.
Autozone identified an upstream O2 code. I replaced this sensor, even though O2 is closed loop operation.
From here, the IAT seems like a good choice, though it has not thrown a code.
Any ideas appreciated!
#2
#4
#5
Fast-forward 2 months...after changing upstream O2 sens (creating code), ECT, plugs, I'm back to square one. With the cooler weather upon us, the S60 still shows a very rough idle between 1100-1300 with some addtl surging upon initial cold start-up.
As stated prev, leaving the key at 'start' for 30 seconds before turning it to 'crank', seems to have some affect on the trouble. Doing this causes the car to operate more smoothly. I believe that the O2 sensors are being pre-heated by first leaving the key in start. However, why SHOULD this have any affect when the car runs in open loop at start-up?
Along with all of this, I can hear some kind of a motor or device which seems to be searching for a set position as the key is initially turned. I don't recall hearing this device cause so much noise previously. There is a good 4 or 5 seconds worth of 'searching' going on.
Any help would be appreciated. Thanks.
As stated prev, leaving the key at 'start' for 30 seconds before turning it to 'crank', seems to have some affect on the trouble. Doing this causes the car to operate more smoothly. I believe that the O2 sensors are being pre-heated by first leaving the key in start. However, why SHOULD this have any affect when the car runs in open loop at start-up?
Along with all of this, I can hear some kind of a motor or device which seems to be searching for a set position as the key is initially turned. I don't recall hearing this device cause so much noise previously. There is a good 4 or 5 seconds worth of 'searching' going on.
Any help would be appreciated. Thanks.
#6
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zmontgomery
Volvo 260, 760 & 960
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03-23-2009 11:26 PM