v70 idle speed problem
#1
10-25-2010, 01:17 PM
v70 idle speed problem
Hi,
1997 registered v70, b5252s engine (10v na) auto in the UK, first hint of a problem was the idle speed going up from normal to about 1000-1100, still driveable, but not so pleasant as it doesnt slow down like it should, replaced the iac valve (as I had a problem with this 3 years ago) {but fixed it by cleaning the iac valve which was gunked up} and the tps, made no difference, at idle, if you pull the plug on the iac the revs go back to normal, so something is telling the iac to open a bit no fault codes stored other than the ones you would expect after pulling the iac plug;-; replaced the ait (intake air temperature sensor) no different, got a new map coming this week, but wondered if anyone had experienced a similar problem and what their solution was, there are no air leaks as far as I can tell and last week an emission check was fine, very good indeed,
it really would be nice to know the logic behind this problem
Thanks for looking
1997 registered v70, b5252s engine (10v na) auto in the UK, first hint of a problem was the idle speed going up from normal to about 1000-1100, still driveable, but not so pleasant as it doesnt slow down like it should, replaced the iac valve (as I had a problem with this 3 years ago) {but fixed it by cleaning the iac valve which was gunked up} and the tps, made no difference, at idle, if you pull the plug on the iac the revs go back to normal, so something is telling the iac to open a bit no fault codes stored other than the ones you would expect after pulling the iac plug;-; replaced the ait (intake air temperature sensor) no different, got a new map coming this week, but wondered if anyone had experienced a similar problem and what their solution was, there are no air leaks as far as I can tell and last week an emission check was fine, very good indeed,
it really would be nice to know the logic behind this problem
Thanks for looking
Last edited by tobydell; 10-25-2010 at 01:29 PM. Reason: added qualification to make sense
#2
03-08-2011, 07:48 AM
idle speed still a problem
Well I thought I had fixed it, replaced iac valve air intake temp sensor, coolant sensor, manifold absolute pressure, and tps, did the battery disconnected routine to drain capacitors, and relearned the ecu to idle, and it was good, for a while, week or 2, then the idle speed went up again, to 11 1200 at no throttle ie traffic lights or wherever, so car is trying to move
so I got a replacement ecu, made no difference, been running without the iac valve connected, goes fine, except might stall when cold,
without the iac valve connected, the revs would almost hunt at tickover (idle speed)
just increase a tiny bit then back almost undetectable, so, having been told previously that the O2 sensor was fine, I decided to change it anyway, and guess what, no change
it seems to me that everything in the loop, which could affect idle speed has been replaced or eliminated
so what is missing, what else could affect this 130k on clock regularly and properly serviced
I repeat what I said in the original post, at idle speed, some signal it telling the iac valve to open a little bit, but what? any ideas anyone, Please
so I got a replacement ecu, made no difference, been running without the iac valve connected, goes fine, except might stall when cold,
without the iac valve connected, the revs would almost hunt at tickover (idle speed)
just increase a tiny bit then back almost undetectable, so, having been told previously that the O2 sensor was fine, I decided to change it anyway, and guess what, no change
it seems to me that everything in the loop, which could affect idle speed has been replaced or eliminated
so what is missing, what else could affect this 130k on clock regularly and properly serviced
I repeat what I said in the original post, at idle speed, some signal it telling the iac valve to open a little bit, but what? any ideas anyone, Please
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