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89 325i Rough Warm Idle And Other Odd Problem

4K views 8 replies 2 participants last post by  mattpark 
#1 ·
I have an 89 325i that starts to idle rough when it gets warm. It was previously idling poorly all the time, a cracked breather hose cured most of it.

When it warms up, it's like a light switch, all of the sudden, the idle drops to around 500rpm and it gets very rough.

I've searched for about 2 hours but I don't think I've found what I'm looking for. I will double check vacuum leaks, test the fuel pressure (I've seen a few where fuel pressue regulators have come up), and maybe try adjusting the idle if possible.

Any other ideas?

Another problem it has is the engine will completely shut off for a split second, and the check engine light flashes for the split second that it's happening, but it turns right back off and the car continues to run fine otherwise. I noticed it doing it under hard acceleration, but now it's doing it at low rpm light load situations as well.
 
#2 ·
Originally posted by mattpark@Mar 7 2005, 01:06 AM
I have an 89 325i that starts to idle rough when it gets warm. It was previously idling poorly all the time, a cracked breather hose cured most of it.

When it warms up, it's like a light switch, all of the sudden, the idle drops to around 500rpm and it gets very rough.

I've searched for about 2 hours but I don't think I've found what I'm looking for. I will double check vacuum leaks, test the fuel pressure (I've seen a few where fuel pressue regulators have come up), and maybe try adjusting the idle if possible.

Any other ideas?

Another problem it has is the engine will completely shut off for a split second, and the check engine light flashes for the split second that it's happening, but it turns right back off and the car continues to run fine otherwise. I noticed it doing it under hard acceleration, but now it's doing it at low rpm light load situations as well.
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ICV valve clean it, and your MAF also could be your throttle possitioning sensor/ does this happen when you rev it or when you just let it idle? check everything with a multi meter and clean your icv and MAF the icv tends to stick over time and can cause problems as described.
 
#4 ·
Originally posted by mattpark@Mar 7 2005, 08:25 PM
The ICV moves freely. It's more of a misfire at idle once it warms up, and continues as I accelerate to about 1500 rpm, then goes away.
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ooo its your timing, your car doesn't have the motronic right? if you dont know how to time it then take too long he would prolly do it while you wait and then that should take care of it.
 
#5 ·
The car keeps throwing a code for the coolant temp sensor. The temp sensor is new, tests good, and the wiring checks out. I'm done working on this POS.

>ooo its your timing, your car doesn't have the motronic right? if you dont know how to time it then take too long he would prolly do it while you wait and then that should take care of it.

That post makes no sense at all. Who is "he"? :wtf
 
#6 ·
Originally posted by mattpark@Mar 8 2005, 11:04 PM
The car keeps throwing a code for the coolant temp sensor. The temp sensor is new, tests good, and the wiring checks out. I'm done working on this POS.

>ooo its your timing, your car doesn't have the motronic right? if you dont know how to time it then take too long he would prolly do it while you wait and then that should take care of it.

That post makes no sense at all. Who is "he"? :wtf
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haha i duno i was pissed when i wrote that. after you changed it did you try reseting the ecu? disconect the battery for a while and then reconect it see if that helps. are you sure its the coolant temp sensor? there is 2 temp senors in the block 2...
 
#7 ·
Now that so called BMW shops can't seem to figure it out, I'm back at it.

Here's the latest symptom. The car misfires when it's warm, and it's like the ignition is turning on and off sometimes.

Is there some sort of main relay or something that might need replacement?
 
#8 ·
Originally posted by mattpark@Mar 16 2005, 05:00 PM
Now that so called BMW shops can't seem to figure it out, I'm back at it.

Here's the latest symptom. The car misfires when it's warm, and it's like the ignition is turning on and off sometimes.

Is there some sort of main relay or something that might need replacement?
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maybe your rotor and cap. also there is the main relays under the wiring cover, there is 3 on my car, on my friends 88 there is a box with them in it in teh engine compartment.
 
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