3 weeks after having the fuel pump/filter replaced for a no-start condition, my '97 540ia engine started surging in city traffic after a 2 hr drive. The idle would jump from normal to 1000-2000 rpm and back to normal; it never bogged down. There was no CEL, a new ICV didn't fix it, eventually it flooded and wouldn't start. But finally, a coolant temp sensor code came in. Replacing the sensor fixed it. There was never overheating, and the temp gauge always showed normal. The car runs great with 173k miles.
My 540 was starting to idle roughly and hesitate on light acceleration, when I removed the ICV it was frozen/varnished almost 2/3 way closed. After prodding with a dowel and almost a full can of CRC I reassembled and the results are stunning. Thanks for pointing out a basic PM which should be part of every E39 annual maintenance.
My idle valve was stuck too and I got it loose by spraying brake cleaner into it. Now the valve moves very freeley.
I don't have any carburator cleaner, do you think brake cleaner is sufficient or is carburator cleaner better?
What do you think of filling a 50/50 mix of acetone and atf into the valve?
Such a mix is well known for removing carbon deposits and dirt in cylinders.
I am sure that mix would get rid of all dirt within the idle control valve.
I used brake cleaner and had zero issues. Just make sure that the little "window" inside moves freely when you hold the icv in your hand and rotate your hand. It should "clink". Hope this helps! Cheers
project for monday morning? i think so
First post, here =) Just did the ICV clean on my '97 540i this afternoon...super easy. The valve was moderately dirty and only moved a little. Cleaned with CRC TB cleaner until both sides shined. Results: Idles a bit smoother on cold start and seems to take less to give it throttle. By that, I mean that I can now 'tip toe' on the accelerator pedal and it goes.
Thanks for the write up!
awesome write up! dont know anything mechanical. this took me two minutes and now the gears arnt lagging and the car is not stalling !!!! Thank you
2000 e39 here, the ICV is a little harder to get to. You have to remove all air intake housing/tubes, remove DISA (wipe clean or use CRC throttle body cleaner while it is out), and jiggle out the ICV which is tucked under the throttle body. Make sure the metal ramp/flap moves by pressing it. Reverse the process making sure to follow the air glow arrow on ICV (little tube/T goes in grommet housing first). While you have the boots off the throttle bottle uses CRC throttle body cleaner to spray it out, keep in mind you must move the throttle cable on the right to open the flap on the inside.
This is maybe already asked, but does this work on a 2000 BMW 528i ?
Thank you
This is something I did after getting a bunch of codes AFTER I replaced my MAF as the culprit from the first set of codes. I took the ICV off and cleaned it as part of replacing this time, the number 5 coil (original factory BMW 7/98 stamp on it) and the new MAF a week ago. HUGE DIFFERENCE! Thanks for sharing. FYI, my gasket from the ICV to the manifold was good so I just cleaned the old sealant off of the unit and put new sealant on it...
I did this a month ago along with a lot of other maintenance and yes it makes a hell of a difference. UPDATE: My E39 sat a few days and was running great after putting a new MAF, replacing a coil, cleaning the ICV and replacing the air and cabin filters. That was a month ago after she was stalling at stops, rough idle before stalling and misfiring bad. Now she's back to misfiring! I'm baffled. All she did was sit for a few days and was running great when I parked her. I wanted to ask you all when putting the ICV back on, I cleaned the old sealant off of the ICV and put new sealant (#4) marked above where it attaches to the manifold. Could that be an area of concern? Is that gasket easy to identify if it's bad? Just guessing here as I have no clue what the hell happened... Any ideas???? Thanks! Here's what I did a month ago: http://www.bimmerforums.com/forum/sh...2188854-Update
- - - Updated - - -
>>>>>>>UPDATE: I just pulled codes and here's what I have (TripleTTT are you reading this :-) PO330, PO505, PO325, PO307 (this one came up more than once and is the only one that repeated itself) PO173, PO325 So cylinder 7 is now misfiring (I replaced coil #5 a month ago (see hyperlink above) and it looked to be original...) Not sure if it's a plug or coil--how do you know? Well there you have it... 350kish and still clicking... Any and all input is always appreciated. Thanks!
Last edited by 300kplus; 07-31-2015 at 06:26 PM.
So, anyone have any ideas for what might be causing these symptoms on a 2001 540i? The idle just bottoms out and the car shuts off, no idea what causes it. As long as I'm on the gas everything works, power is great, but as soon as I stop the car shuts off. I'm waiting on a new MAF, but wondering if anyone has any other ideas?
Don't know what controls idle on the 2001; if it has an ICV, clean it.
My '97 540, which runs fine and idles perfectly, would stall often enough if it the clutch was depressed when it had been running at highway rpm, like when getting off the highway at an exit ramp. Idling at a light, it never stalled.
If the rpm dropped rapidly, it would keep dropping, then either the rpm would 'catch', as if bouncing off zero, jump to ~1200, oscillate for a second or two then settle down to ~700. Or, the rpm didn't bounce back, but fell to zero and stalled, as if there was lag in a control system. Roughly 50/50 chance.
I thought it might be an ECM software problem (car is an early example), or ICV lag. Couldn't do anything about software, so I cleaned the ICV.
It was only slightly dirty (was cleaned years ago; car has only highway miles). A quick rotary flick would cause the flapper to hit the internal stops. But it's hard to know just how easily it should rotate, or if it's free enough. That test isn't exactly reproducible. But my impression was that cleaning caused it to hit the stops with a more noticeable click.
Maybe imagination, but in similar situations since, it hasn't stalled. Engine rpm drops smoothly to ~ 650, without rebound or oscillation.
Now, if only the SW wasn't so persnickety about shutting the engine off if it's not fed *exactly* the right amount of gas when the clutch is engaged at idle. Geez, for an engine with such torque, it should be at least as robust as my '86 535i. On that car, with engine idling, you can dump the clutch and it won't stall; it just pulls away. No SW beast to feed?
HTH
-Fabrice
Absolutely I likely know what the problem is.
Its the drive by wire (DBW) throttle body (TB).
In essence an ISV/ICV is a computer controlled mini-TB for idle stablization... on the DBW cars its not needed since the DME can use the actual TB.
@Diren, the DBW TB has a known failure mode where the insides (inside is a servo motor but also several position-sensing potentiometers) get dirty/dusty and then the pot tracks get contaminated so the DME gets a false signal for where the throttle plate is. I've posted up a bit on this lately. Your symptom is a common "early warning sign".
That said it also could be a vacuum leak, but I will admit this TB thing is my pet chip on my shoulder because I've wrestled with it all too much since some of the new off the shelf VDO's kinda suck...
Unlikely it's the MAF.
Have a look at this info. Note my bit about testing this by working the plate back and forth a bunch by hand and seeing if the problem goes away for a while. Also note the codes are fairly reliable for this or accelerator pedal or MAF.
--- EDIT --- ooops I have 3 threads at least on this topic... THIS one is the latest one... ------------------
http://www.bimmerforums.com/forum/sh...hrottle-Bodies
Read the posts there, in fact I should probably post a quick update....
Last edited by geargrinder; 07-17-2016 at 09:51 AM.
2003 M3CicM6 TiAg
2002 540iT Sport Vortech S/C 6MT LSD TiAg
2008 Audi A3 2.0T DSG (the daily beater)
2014 BMW X1 xDrive28i (wifemobile)
Former:
1985 MB Euro graymarket 300SL
1995.5 Audi S6 Avant (utility/winter billetturbobattlewagen)
Reviving this DIY with this info I found since I was about to remove the ICV again to clean it after a couple of recent episodes of stalling and throttle lag from idle.
I don't see this e46 post linked in this thread, but it contains a lot of interesting details about the inner workings of the ICV: https://www.e46fanatics.com/threads/...n-icv.1043323/
The TL;DR is: When you clean it, always keep the motor and electric plug facing up (inverted T) until the cleaner dries out and then put some drops of engine oil inside and turn the ICV around. Besides the risk of killing the motor with the brake/throttle cleaner, there are 2 bearings inside the ICV. Brake/throttle cleaner will dissolve the factory lubricant inside those bearings and the valve will eventually become sticky again, not because it's dirty but because the bearings are bone dry.
There is also this thread from MBWorld that shows how these "revolving door" ICVs react to different applied voltages: https://mbworld.org/forums/e-class-w...l-voltage.html
Better understanding how they work helps in properly understanding what you are doing when you clean them and how to avoid killing them. I suppose I have caused tons of wear on the bearings after several cleaning sessions with no subsequent lubrication. I'm at around 170k miles.
Last edited by crdiscoverer; 03-15-2021 at 03:51 AM.
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