Help with fluctuating idle
Moderator: martauto
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chopper
- E30 Zone Regular
- Posts: 478
- Joined: Sat Nov 28, 2009 11:00 pm
Hi guys, hopefully someone can point me in the right direction. I got the cabby m20b25 cabby converted from auto to manual and since doing the conversion the mechanic can't get the idle to stop pluse revving, and whilst doing this he's unplugged the icv and the engine will automatically Rev to the limit. He tested the throttle position switch and replaced it but the problem is still there. We have checked all hoses for air leaks and Made sure the wiring is connected. Does the ecu need changing due to the swap?
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jslot
- E30 Zone Regular
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- Location: Isle of Man
Pulsing idle is caused when the ECU has been disconnected from the battery and losses is idle memory. People say you just need to let it idle for ages but I have found driving it around normally for a bit will sort it out.
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steve_k
- E30 Zone Team Member
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- Location: in the vale of mansfield
normal way is when the battery is reconnected to let the engine idle for about 10mins then drive it for a while to "relearn" all it's settings.jslot wrote:Pulsing idle is caused when the ECU has been disconnected from the battery and losses is idle memory. People say you just need to let it idle for ages but I have found driving it around normally for a bit will sort it out.
if it's got t*ts or wheels it's bound to be trouble...............prove me wrong.
getting oral sex off an ugly person is like rock climbing.....don't look down ;)
getting oral sex off an ugly person is like rock climbing.....don't look down ;)
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chopper
- E30 Zone Regular
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- Joined: Sat Nov 28, 2009 11:00 pm
It engine revs high so it's like a kangaroo if you try to drive it. Strange thing is the car started and drove fine on first start up then a day later this problem occurred. I'll give it another go over the weekend thanks.
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Brianmoooore
- E30 Zone Team Member
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Unplugging the ICV on a M20B25 should have no effect whatsoever, until engine load changes. The ICV is essentially one motor opening it, fighting another motor trying to close it, so if both motors are disconnected at the same time (by pulling the plug) it should remain exactly as it was.
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chopper
- E30 Zone Regular
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Hi guys, so I left the car started for 10-15mins then tried to drive it but it won't accelerate, so cannot drive it. Maybe it needs longer to relearn it's idle??
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Brianmoooore
- E30 Zone Team Member
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So what's the latest on the ICV problem??
Idle speed learning has nothing to do with the car accelerating. If it won't respond to the throttle pedal, the ECU isn't getting a signal from the AFM, and the mixture becomes excessively weak as air flow increases.
Idle speed learning has nothing to do with the car accelerating. If it won't respond to the throttle pedal, the ECU isn't getting a signal from the AFM, and the mixture becomes excessively weak as air flow increases.
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318isPMK
- E30 Zone Camper
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this again sounds like mine.
