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-   -   03 325xi Idle Surge (http://forum.e46fanatics.com/showthread.php?t=808475)

Chadrobb4 12-03-2010 01:19 PM

03 325xi Idle Surge
 
Hi all, I have an 03 325xi that is surging when coming to a stop/idle. Right around 1k RPM it will surge quickly 500RPM and settle out. I know there are a few threads out there on this topic.

Ill be checking codes and look for leaks, but most of that has already been changed and no check engine lights.

One thing I do need to do is replace the thermostat as it threw a P0128 (I know I just said it hasnt had any check engine lights, hasnt had any new check engine lights) and the engine is running very cold with the winter temps coming in.

Is the most likely cause related to the fact it needs a thermostat? Also thinking about changing the VANOS seals while I have the mechanical fan out.

Any info is greatly appreciated.

Capt1014 12-03-2010 01:34 PM

I have the same thing happening to mine, but it's always been like that since I bought it a year ago (02 325XI) :hmm:

Chadrobb4 12-03-2010 01:49 PM

Its quite annoying! I fix one thing, another pops up.

SamDoe1 12-03-2010 02:38 PM

If you have to change the t-stat then just do it and see what happens. Other things to look at would be the camshaft position sensor and/or the coolant temperature sensor.

Capt1014 12-09-2010 03:53 PM

Quote:

Originally Posted by SamDoe1 (Post 12533606)
If you have to change the t-stat then just do it and see what happens. Other things to look at would be the camshaft position sensor and/or the coolant temperature sensor.

Coolant temp sensor can make the idle surge?

SamDoe1 12-09-2010 04:29 PM

Quote:

Originally Posted by Capt1014 (Post 12556889)
Coolant temp sensor can make the idle surge?

I would think so, if the coolant is cold the engine will idle higher than if the coolant is hot. Turn your car on on a cold day and it will idle quite a bit higher than after you drive it for 20 minutes. Any variation in this signal could vary the idle speed of the engine.

E-rock 12-09-2010 04:40 PM

My previous car had an idle surge in cold weather. Very annoying. It ended up being a temp sensor.

Kubica 12-09-2010 08:26 PM

It's probably the DISA. Search for the video on here that shows the difference between a broken and new DISA valve.

mp333 12-09-2010 09:40 PM

Try disconnecting the DISA, see if there's any change. Also is the ICV clean?

E-rock 12-10-2010 08:43 AM

Quote:

Originally Posted by mp333 (Post 12558178)
Try disconnecting the DISA, see if there's any change. Also is the ICV clean?

I've never known or experienced a dirty ICV to cause the rise and fall the OP described. Rough idle, yes, but not a rhythmic, surging idle. Couldn't hurt to clean the ICV if it hasn't been done in the past year or two but my guess is a temp sensor has gone bad, or worse, coolant isn't coming into contact with the sensor.

Kubica 12-10-2010 01:51 PM

Quote:

Originally Posted by E-rock (Post 12559388)
I've never known or experienced a dirty ICV to cause the rise and fall the OP described. Rough idle, yes, but not a rhythmic, surging idle. Couldn't hurt to clean the ICV if it hasn't been done in the past year or two but my guess is a temp sensor has gone bad, or worse, coolant isn't coming into contact with the sensor.

Nah, it's the DISA.

Capt1014 12-10-2010 02:38 PM

Quote:

Originally Posted by kubica (Post 12560344)
nah, it's the disa.

disa?

nickchuck 12-10-2010 02:55 PM

Probably the DISA Valve. http://www.ecstuning.com/Search/11617544806/ES25794/ You can disconnect this on your own very easilly. If it flaps open and closed (no spring tension) it's broken.

If not check the coding of your computer. I had mine updated with the newest software ($129 at the dealer) and all my idling issues dissapeared. This may be a good idea if you haven't done it recently anyway.

Rickna 12-10-2010 04:44 PM

Quote:

Originally Posted by Capt1014 (Post 12560576)
disa?

Air Adjustment Unit


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