X5 4.4 2004 no compression on one cylinder

[fieldy1978]

X5 4.4 2004 no compression on one cylinder

Hi everyone. Wifes x5 developed a missfire. Plugged in code reader and got the vague multiple missfire code. Finally got round to getting on it today. Removed all coils and plugs and YES. One plug was black. New coil coming up but thought hmm compression test just incase! And yup zero compression. All others are fine just cylinder 2. Left bank 2nd cylinder from front. Potential of finger issues or burnt valve?

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fieldy1978*said:Today*02:19 PM

Ok had apart several times and still not right. The tappet was over extended so i put a new one in but i think there must be wear on the follower/finger. Anyone heard of this ?

[Bmwtek3]

0 compression huh? I'd take a look inside that combustion chamber with a boroscope if I was you and look for burnt valves or do a leak down test

[fieldy1978]

Thanks bmwtek3. I got my cam in there and all good. Leakdown test is one inlet valve failing as its held open by the rocker. Think i have an answer now. The eccentric shaft is pretty worn either side and allowing the finget to push forward. Bmw want 850 quid for a new one. Just bought a whole second hand low mileage head for 190 on ebay. Going to measure up and compare but looking promising. Just hoping i can remove the eccentric shaft without upsetting the timing.

[Bmwtek3]

Wow I'm a noob haha didn't recognize we were talking n62 motor here , don't really work on that many e53s. But I think your right on with eccentric shaft and levers. They wear right along the idle part of the eccentric shaft and the intake valve will not open at all rather than stay open , resulting in that cylinder not being able to suck in any air for compression.

[fieldy1978]

No it holds it open.( I know it took me ages to work it out). Because the shaft is worn the finger moves towards the valve only a couple of mm. The valve pushes down and the lifter rises up. Hence the knackered lifter initially. It runs perfect unless under load. It will cruise all day long. It will kick down and go happily but the wrong amount of throttle and the misfire develops(must be the certain point on the eccentric cam. I have heard of lumpy idle but my idle is fine. Very strange!

[fieldy1978]

New cam fitted today and its like a race car!!

[brv44141]

Gentlemen I realize this post is older, but after reading it I am having possibly a very similar issue.
I have a 750i with N62 engine in which I did a valve stem seal replacement using the AGA tool. After everything is back together it runs terrible. The scanner reads several codes such as CAM sensor and misfire on cylinders 1-2-3-4. I replaced the sensor same code and problem. I did compression test, all cylinders on the troubled side and have zero compression. This is to my surprise because the car ran fine prior to doing the job, and I also hand turned the engine prior to finishing the job just in case, and there was no problems. Could there be a broken wire, bad IVM computer, the timing / Cam “slipped”, or something else? I am out of ideas other than bent valves, but the car ran fine prior it just smoked bad.

[MarcoZandrini]

You should start your own thread as some folks won’t be interested in OP’s engine.

That said, go back and check your work.