07 X3 weird idle issue and surging

[englishtom1596]

PROBLEM SOLVED


Hey everyone,

Just bought my wife a 2007 X3 with 91K on it. When we bought it the idle would surge every so slightly for about 10 seconds after start up. Figured it just needed a tune up so i did front diff fluid, trans filter and fluid, transfer case fluid, oil change, oil filer, air filter, cabin air filter, valve cover gasket, and spark plugs. I also did coils at first but the car was misfiring like a pig after those so i switched back to the old ones.

After doing all that the issue at idle got worse and you could now feel the car shake as the engine surged. Unplugged the MAF and the problem went away. Well the wife was driving it and started to buck and kick so she took it to the dealer who pulled nothing but a MAF code (from me unplugging it). Other than that they said it drove fine so they didn't touch it.

ordered a New VDO sensor and it arrived last night and its STILL doing it. it has gotten better only jumping up and down about 50rpm from the 500rpm idle. Also after i've been driving it all day i'm now getting some shuddering in 3rd gear where it feels like its surging instead of accelerating smoothly.

I'm really at a loss at this point. I've heard these things have transmission problems, I've heard the chain in the transfer case gets loose and slips, i've heard fuel injectors clogged and i've heard software updates. I just can't keep dumping money into this thing and BMW seem totally disinterested in actually diagnosing anything.

any help would be appreciated. I'm wasting money on this thing when my e36 M3 needs love

[dukedkt442]

Until you pull the codes (the real ones, not the ones that auto zone or most shops will pull) anything is a shot in the dark. From everything you did, plugs and coils are most important. If the coils made it misfire, you either got a bad coil or didn't install it correctly. Reinstall all of them, Disconnect one by one until you find the problem. TC fluid should be changed every 25k miles. I hope you used only the BMW fluid or you made the problem worse. After going almost 100k before changing the TC fluid, you probably need to have BMW reset the TC adaptations. Other things to look for: DISA, VANOS check valves, VANOS solenoids, vacuum leaks... The list goes on and on without reading the stored codes.

[englishtom1596]

BMW were the ones who pulled the codes and there weren't any other than the MAF but i also unplugged the sensor to try and diagnose the sensor.

The weird thing about the coils is Realoem gave me the part number for one set, then when i searched them FCPeuro sent me a different part number and different to the ones that were installed in the car... so i don't really know which is correct.

the Tcase fluid was done with BMW fluid along with everything else. I only put OE parts on my cars to avoid doing things twice.

looked at DISA's but they don't make any noise at idle like everyone says and the car has plenty of power which i also feel eliminates vanos issues. vacuum leaks... who knows. I did find the exhaust tip valve line disconnected but i plugged that back in. Don't know where that connects in the engine bay?

[dukedkt442]

I'd get them coils back in. Depending on the brand and source they may have alternate part numbers. If you order from BavAuto or FCP or ECS they are great vendors and you can rest assured they are the proper coils. I had my first fail at 82k so it is a reasonable bet that yours needs coils.

[Chamberlin]

We just got a '07 X3 for my dad this evening, and its doing the same thing. Unstable idle on startup, shuddering juttering only when in reverse backing down the driveway slowly. The battery totally died as soon as we for home so we had to run to the nearest Oreilley's and drop almost $200 within 1 hour of owning the car. LOL.

The MAF sensor is a Seimens unit I think, and I removed it to clean it....but it looked brand spanking new, like somebody just changed it. Same with the (very weird) air filter.

Near term plans are new spark plugs, oil change, differential, t-case, tranny fluids, filters power steering flush, and maybe DISA or other related systems.

I'm gonna hate working on this car as compared to my S52s!

[englishtom1596]

Just wanted to update this thread as i found the fix awhile back and hate when people don't tell how they fixed problems.

After it visiting an independent BMW shop and the dealer, neither could identify the problem and just wanted to throw the same parts at it which i had already replaced (read first post).

So I decided to go on my scanner and said screw it and cleared all adaptations (which basically resets all the perimeters) and voila!! it stopped the problem instantly...for at least awhile. So after doing this i knew it was NOT MECHANICAL, that it was in fact computer related. kept searching old threads and i found info about eccentric shaft sensors which commonly go bad causing oil to penetrate the sensor (Located under the valve cover and attached to the front of the exhaust cam to measure how much the eccentric shaft motor is moving the camshaft). I started researching this problem and found it caused the same problems I was having, stumbling, hesitation, falling on its face etc.

Needless to say i pulled the valve cover off...for the 3rd time, installed the new eccentric shaft sensor (with new valve cover o-ring seal), cleared adaptations and DONE!! FIXED!! Car has now done around 10K and all good.

I still have the idle bounce on initial start up but have been unable to locate the cause yet.

hope this helps anyone with similar issues. I must say i'm amazed at how riddled with gremlins these things have, I don't know what BMW was thinking but it really makes me appreciate my pre 2000's BMW that much more.

[Chamberlin]

Thanks for the update on this issue! Of all the other things that can go wrong and cause these problems, this one is at least one of the easier fixes that should be tried first. Aside from my dad's X3, I've since got an E91 wagon with the same motor, so I had better get used the N52 quirks!

[englishtom1596]

I just can't believe how bad BMW sensors were during this period. Just cheap plastics and overly complicated. We ended up trading our x3 in recently because I just got sick of chasing down problems on it constantly. Something to be said for warrantee and a cheap lease payment.

[CynicalBjorn]

Thanks for the update on this issue! Of all the other things that can go wrong and cause these problems, this one is at least one of the easier fixes that should be tried first. Aside from my dad's X3, I've since got an E91 wagon with the same motor, so I had better get used the N52 quirks!

I know it's a bit old, but any chance you remember what codes you were getting? Having similar problems with my X3

[jclausen]

Valve tronic sensor pull off the plug and see if oil is in there located at the front part of the valve cover

[englishtom1596]

exactly. mine didn't have oil in it though and wasn't throwing codes yet.