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-   -   N62B44 - Idle Surge - Jumpy Throttle at Idle Speed (https://xoutpost.com/bmw-sav-forums/x5-e53-forum/108702-n62b44-idle-surge-jumpy-throttle-idle-speed.html)

dkuchan 08-22-2018 12:26 PM

N62B44 - Idle Surge - Jumpy Throttle at Idle Speed
Hey Guys,
I'm new to the forum, but I can't find any threads that seem to fit my problems so I figured I'd post.

I have a 2004 E53 with the 4.4 and my current problem is that I get idle surge but it's intermittent. I also have the intermittent issue where when I put the car in drive and touch the accelerator it will sometimes act as if there is a dead zone at the very beginning of pushing the pedal where nothing happens (it's a very small amount of pedal travel), but then when it responds the car lunges forward and it jerks (rpm's fluctuate) with the pedal if you hold it in that position where it first responds. This means that in a parking lot or driveway the car will lunge/surge at just above idle speed. When this is occurring I also have some problems with coasting RPM being too high which then appears to lead to downshifting issues. I also have a rough idle at times that will shake the car and it seems to come and go as well. These problems may all be related, but there isn't always a correlation between rough or surging idle at startup and the jumpy throttle response problem.

I had some low-end power issues as well, so I thought maybe the Vanos system was to blame for all these problems, but I replaced all 4 solenoids (with the genuine BMW solenoids) and these problems still linger. My low end power is better and the car does seem to run better so I did have some problem with the solenoids, it just wasn't the silver bullet I'd hoped it would be.

I am not throwing any codes.


Any ideas on what the root cause (or causes) might be? Any help is much appreciated.

srmmmm 08-22-2018 05:40 PM

I'd start with a thorough check for vacuum leaks, then move on to the idle control valve:


2002 X5 3.0 347,000 miles
2014 428i 39,000 miles

2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

1970 Firebird Under restoration - time for paint

amancuso 08-24-2018 08:28 AM

N62B44 - Idle Surge - Jumpy Throttle at Idle Speed
The problem with shifting is most likely the valve body and solenoids in the transmission.

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dkuchan 08-24-2018 12:25 PM

Thanks for the replies and the help.

As far as the vacuum leak and idle control valve go; I have the N62 and I can't seem to find anything on any idle control valve. I did actually just start getting some codes as well.

P0300 - Random/Multiple Cylinder Misfire Detected - Confirmed

P0001 - Fuel Volume Regulator Control Circuit/Open - Freeze Frame
P0103 - Mass or Volume Air Flow Circuit High Input - Freeze Frame

This does seem like a vacuum leak or mass air flow sensor malfunction could be my problem. I did just order new crank case vent valves. I'm going to try to get those in this weekend if they are delivered in time...maybe I have a torn diaphragm or something.

Any thoughts?

bcredliner 08-24-2018 01:12 PM

MAF could be the problem. I would troubleshoot it by disconnecting the connection to the MAF and see if engine idle smoothes out. If you don't know the last time the MAF was replaced or cleaned I would clean it and the throttle body to see if that helps before purchasing any parts. If you decide to clean the MAF only use MAF cleaner. Spray liberally. The important wires to clean are kind of hidden. A common symptom of a bad MAF is the engine seems to be roaring when you increase the RPMS and noticeable loss of acceleration. This video should be helpful: https://www.youtube.com/watch?v=aDlHCjgYf8s

Vacuum leaks are usually not intermittent. I agree to check for vacuum leak but based on your situation troubleshooting probably won't be conclusive unless you do a smoke test.

Did these all start at the same time or have the symptoms gradually gotten worse and the number increased of a fair length of time?

Helps getting applicable input if you put year and model of you X5 in your signature.

dkuchan 08-27-2018 12:23 PM

Thanks for the tip on updating my signature!

I cleaned my MAF sensor and throttle body this weekend and it does not appear to have affected my problem(s). I cleared my codes as well and it didn't take too long for them to come right back (at least the misfire and the fuel volume control). This problem does appear to be way worse when the engine is cold and once it reaches full operating temp it runs a lot better and sometimes I'd even say it runs pretty close to what it should. I also inspected my crankcase ventilation valves and they appeared to be in good working order (still good and rubbery with no visible cracks). I didn't get my new ones in time to swap them out, but they should be here today. I also checked my duct from the MAF to the throttle body for cracks and it appears to be fine. I haven't checked for all potential vacuum leaks yet, but I checked a few accessible joints with carburetor cleaner to no avail. I'm going to see if a local shop has a smoke machine so I can avoid spraying carb-clean all over plastic and rubber parts.

Whatever the problem is, I started seeing it around January time-frame, but it was very infrequent and it got better as the temperature up here got warmer (I live in Michigan so it's a dramatic shift through the seasons). At first it was intermittent (and still sometimes is), but it's more frequent than not at this point. I also just changed the oil and switched from 40w to 30w and it seems to have made it worse. It seems like this is probably only a coincidence, but I figured I'd throw it out there in case someone thinks it means something.

I'm just hoping it's not my intermediate levers/eccentric shafts, but I figured with it being intermittent that these were probably not the cause. Any thoughts?

dkuchan 08-31-2018 01:18 PM

The other night I change out my CCVV's and it didn't help.

I did take it for a ride the other night after it was already run up to temperature and then shut it off, and after restarting while at operating temp it ran like a top (better than it probably ever has for some reason). So, the next day I was at work and when I went to leave work (car was ambient temp) it ran like crap...idle surge, jumpy throttle at low speed across the parking lot, etc. When I got across the parking lot and was about to pull out of the driveway I decided to shut it off an restart it to see if I would have the same luck I had the other night only when the car was not yet up to operating temp. After restarting it ran pretty good (at least as good as it normally has since I've had it and before the issues). My small dead-spot in my throttle went away and so did the jumpiness and idle surge. It still wasn't a super-smooth idle, but this car has never had a smooth idle since I've had it.

I'm about to leave work right now and I'm going to try to start it, shut it down, and restart it to see if it will act this way without driving it at all. I'm to the point now where the problem isn't really intermittent anymore so it's a little easier to do some testing and troubleshooting.

I don't know what any of this means yet because I haven't had time to really research it or even think about, but let me know if anybody has any thoughts or advice.

oldskewel 08-31-2018 03:40 PM

I don't know much about the N62, but if I can believe the youtube video linked above, it seems the N62 does not have an idle air control valve.

But I will say that on my M54 (3.0i), your symptoms sound exactly like mine did when my IACV was stuck. EDIT - I mean the general symptoms you list up top; unlike your latest post, my problem was constant.

Briefly, I just finished a top-end engine rebuild on it, and had cleaned out the IACV as part of that, creating a problem where none had existed. After reassembling, I found the exact same symptoms you list above. I removed the IACV and it was obviously stuck (the simple test for that is to just gently twist it while holding it in your hand - the valve should gently clang about while doing that, unless it is stuck).

So I cleaned it again, much more carefully this time, which made things perfect again. BTW, I had no problems with the IACV before the rebuild, so all I can think of is that some of the solvent I sprayed in there the first time loosened but did not remove the gunk, and then the gunk settled in a bad spot, leading to the problem.

Hopefully this helps. Maybe whatever the N62 does to replace the functionality of an IACV is the problem for you. ???

dkuchan 08-04-2019 06:48 PM

Update: I still have issues with this...I actually broke down and paid my local import shop to diagnose and they came up empty-handed. After talking to them it seemed like they had no idea what they were talking about so I don't have a lot of faith in anything they told me. They said they smoke-tested it and there were no vacuum leaks. Tested the MAF and it tested good (I ended up replacing it anyway and it didn't help). They re-taught Vanos system (not sure what that entailed).

Anyway, I have also since replaced the spark plugs, Vanos solenoids (OEM), and the IVM. Spark plugs didn't seem to do much, but they needed to be done anyway. The IVM however seemed to help quite a bit (at first). My shifting problem appeared to be gone, but my throttle and idle issues were still there. I also regained a decent amount of power. The shifting problem has returned, but at least now I feel confident that it is related to my other problem(s) and not a mechanical issue with the trans or valve body. My power still seems better so I think the IVM did help solve something (just not what I was chasing). My shifting problem being better after changing the IVM seems to be related to simply unhooking the battery for a half hour or so (planning on testing this theory, but haven't had time yet). I have a subwoofer box in the back and stuff so it takes a bit of time to get in there to unhook the battery. Maybe there's a better way than digging in there?

I have also learned another thing in this process...When I start the car cold (ambient/overnight/70F-type conditions) and immediately take off I get the throttle issues. If I wait about a minute and half the idle will stumble and surge for a few seconds at about that time and then it will level out. If I take off after that happens I don't seem to have the throttle issues. Also, if I do take off right away cold and am experience the issues I can pull over and shut the car off and turn it back on immediately turn it back on and the throttle issue is gone. The 1.5 min waiting period hasn't failed me yet so I think there's something to this, but I have to say that's it's more related to engine temp than time because if it sits for an hour or so the time will be cut down to say 30s instead 1:30.

My new question is, is there something that happens that you guys can think of related to engine temp that can cause this? Emissions control or something?

Also, that import shop told me that the throttle body works in unison with the variable valve lift. That doesn't make a ton of sense to me because it seems like there would be no point to variable valve lift if it worked that way, but maybe I'm wrong. If it's true, could this be an issue with my throttle body? I've cleaned it up a bit, but didn't remove it or take it apart. Just cleaned what I could get at. I thought I read that the throttle body is just a fail safe and in normal conditions it is wide open when the engine is running. Does the throttle body maybe work in unison for that first period when I start the car until it gets to a certain temp? If so, it might be my issue and it might be what the import shop was talking about (even though they claimed it worked like that continuously because I asked this question...I first received the glossy-eyes looked when I asked which is why they didn't seem credible).

Let me know what you guys think because I'm about to drop it off at BMW to pay diagnostics, but I really don't want to do that because it's 40 minutes away and I don't have a spare car or anybody that can help me get to and fro.


crystalworks 08-04-2019 08:33 PM

^Keep this thread updated. The parts truck I bought to get the aero kit off of had this exact problem. Went to 2 local shops (one of which is pretty damn good) and could not figure it out. Unbelievable amount of new parts were thrown at it. It was retimed, new vanos solenoids, new valvetronic actuators, eccentric shaft sensor, etc. You name it. The good shop was baffled and felt bad for the PO. Gave him a break on the repair bill obviously as they are a fairly good shop and were very disappointed to not be able to fix it for them.

^None of that helps you though. Sorry. :)

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