2005 4.4i Rough Idle Turned Nightmare
 

My first post here after lurking for a while. I am at my wits end here trying to diagnose the problem. My 2005 x5 4.4i had the rough idle when cold in the morning but after would be ok. I read here that it was probably the vanos solenoids. I also had Valve cover leaks so I changed out the VCG and all the vanos solenoids. Using ISTA + I reset the learning on the servo solenoids.
So far it sounds like a diesel and has no power.

I have checked and rechecked all of the sensor connections to make sure they are not loose or in the wrong positions. Vacuum lines aren't leaking, however I did notice the PRV on the passenger side valve cover is sucking air through the little nipple thing. I tried blocking that and it seems to make it worse. My battery went dead about a week before I changed the valve covers and I reinstalled a 900 cca AGM to replace it. Voltage checks out 12.8 or so without the engine running. While running its 14 volts.

The error codes Im getting are misfires and vanos. Is there software the will tell me specifically what component is causing issues. I reinstalled the old solenoids and it is still the same. Instead of guessing and throwing money at parts changes what is the best route to take.

Thanks in advance.

Look into intermediate levers and valve minimum adjustments. If the valvetronic system can't set the valve heights correctly you will have terrible idle when cold especially when ambient temp is low.


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I did that and it said they were set at .03 i think. It also is not just when cold now. It is all the time and the X is pretty much not driveable.

What vanos solenoids did you use to replace the OE ones with?

Had the intermediate lever issue on my ‘04 4.4, started at about 65-70,000 miles with symptoms as described here - at temps below 37 degrees ran terrible and sounded like an old diesel until warmed up, ran fine once warm. Dealer proposed cost for repair along unrelated and typical transmission issues led me to replace the vehicle. Hope your issue is simpler.


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Guessing at BMW specification never ends up right. Time to take her in.

:thumbup:

Just ones from ebay but surely all 4 wouldnt be bad would they?
I swapped the old ones back in and it made no difference.

Trying to drive it causes failsafe to kick in now.

Make sure you have proper voltage from alternator

Ebay ones are notorious for being unusable on all chassis. I'm not saying this is your problem, but my bet is that they aren't any better than the OE ones @ whatever mileage is on your X. You'll need some OE/OES ones to truly rule out the vanos solenoids.

To really troubleshoot this you will need a scanner/software that will tell you commanded vanos values vs. actual values. I think (have never tried personally) a Foxwell will give you that data. Hopefully someone else will chime in who has used it for that purpose.