Exhaust Vanos Solenoid disconected
 

2007 Bmw X5 4.8, 90000km

I have a misfire on cylinder 1 on cold startup and also a acceleration hesitation at low rpm.
Misfire is not there when engine is warm and hesitation is reduced as well when engine is at operating temperature.

After checking spark, coil, injectors...

If I unplug the Exhaust Vanos Solenoid on that Bank of cylinders. The car stars great when cold and doesn't have the shudder on acceleration.

My question is:
Why would this happen?
Is Vanos spring loaded in default position or controled by oil pressure?
Valve timing has been changed but wouldnt that mean that my solenoids are bad and not the Vanos seals? I thought Vanos was only for intake valves. I only get codes for the misfire on cylinder 1. Nothing to do with vanos or solenoids or cam timing.
Is my Vanos stuck? If it is wouldn't I get a code for this or multiple misfires?
Totally confused.:dunno:
Can I somehow jump the wires somehow so I dont get an engine light? I am happy with the performance with the solenoid disconected, it has reduced torque but I don't mind. Its better than the misfire.

Just switched Exhuast Vanos Solenoid from one bank to the other with no change. Still rough idle, stumbling low rpm acceleration and misfire on cylinder 1.

Unplug the solenoid and smooth idle, smooth acceleration and no misfire.
No codes except for the misfire.

Really?!?!

Just take it out in the field and set it on fire, report it stolen and collect the insurnace.

Not a bad idea.

Honestly with the VANOS disabled it only affects the low end. WOT is still amazing and at the low end the change is hardly noticable. Keep in mind my VANOS is stumbling on the low end.

Actually I am not even sure the VANOS has gone bad :dunno: maybe its the eccentric shaft sensor or cam position sensor or maybe a temp sensor?

I believe the misfire code is a symptom of something with the timing that has gone wrong. Why? Because disable the VANOS and the misfire is gone.

What controls the VANOS timing?
Temp?
Throttle position?
...
What could go bad and not throw a code?
When the car warms up there is no misfire.

If the VANOS is stuck wouldn't it throw a code?
Any way to unstick a VANOS without removing the valve cover?

Can't sell this thing with the engine light on:banghead:

If you wanted to know 'what is wrong with my car, how can I diagnose this and fix it properly?", I'd be inclined to help.

But if the request is 'how can I screw a future buyer by covering up a defect?' you can get lost.

I was looking at trading it in at a local dealer and they would take it with the engine light on but at a lower rate. Would love to fix it and keep it. Just feeling like I got screwed. Purchased from a small dealer, paid quite a bit of money for a car that has problems.
So many problems with VANOS out there and not many diy fixes. VANOS stuck replace seals $$$$$. Not sure if that is my problem and dont want to waste money at the dealer figuring it out.

Car runs great with exhaust solenoid disconected. This must be a clue as to what is wrong I just want to understand why.

Not trying to screw anyone I have spent weeks of reading and trying things.

Swiched coils and plugs.
Replaced injector on Cylinder 1 (Injector 1 looked wet and was black with carbon, not too much but it wasn't like the other injectors) Valve problem? Timing?
Opened valve cover and looked at intermediate lever spring. Had a huge nightmare putting the valve cover back on. Its back on now and not leaking.
Cleaned VANOS Solenoids.
Switched Solenoids with other Bank with no change.
Cleaned MAF sensor
Tried some seafoam to get rid of the carbon
Suggestions...

So I connected back the solenoid.
I did an oil change to make sure the oil is fresh. VANOS likes clean oil.
Warmer weather has caused less misfires in the morning and the acceleration shudder seems reduced.

Cold weather has an effect on oil pressure? Therefore has an effect on the ability of the solenoid to move VANOS?

Any VANOS experts out there???

All your problems are described in many threads about intermediate shaft levers failures.It may be mixed with other problems,but you need a proper diagnosis.Disconnecting the vanos solenoid probably masks the problem,not solving it.

I was trying to avoid that as a soution but I think you are right. My thought was that with 90000km my X5 couldn't be worn that badly.

I can't find any DIY for the lifters. Can anyone point me in the right direction?
Is this a DIY job or are there too many special tools required?
Can I change one bank of lifters and leave the other bank? I know it would be better to do them all but my DIY skills are already being pushed to the max.

Thanks for all the help.
M

Looks like the timing tools are required because the lifters can not come out from the top. There might be a way to get around using the tools but I would like to know if anyone else has done it. Immobilizing the eccentric shaft once removed is the key part not to disrupt the timing. I watched a video of a guy who tied it with his shoelace lol. I think I can come up with something better.
I cant find anywhere to rent tools that will ship to Canada.

I know this was a long time ago but did you ever workout what the problem was? My 2005 4.8is is exhibiting identical symptoms including misfire on cylinder 1.