Gearbox or electrical??

[oztme]

Hi,

I'm not really knowledgable about these cars yet, but I think I read somewhere that the hot film air flow sensor can play up leading to the symptoms you describe. Is yours a turbo diesel? I assume so...

I also wonder if you have a boost leak? I think they can pressure test for this.

Another thing you could do is go to a tuning shop with a 4WD dyno, and get a power run. Not tuning, just a power vs boost vs rpm vs air fuel plot. They cost about 50$ here in Australia and take about 15 minutes. This has been useful to me in the past diagnosing problems with my rally car (a turbo)

GL & please let us know how you go...

Cheers
Scott

[wallyx5]

I had a very similar problem as well... as soon as I got to 80mph my X5 would kinda shut down and would not produce any more horse power. I took it into the shop and they found two problems. They smoke tested the intake system and found a vacuum leak in one of the elbows. Cheap fix like $18-25. They also tested the MAF sensor and it was not giving the correct reading. I drove for another 1000 miles or so and the problem would come and go. So I replaced the MAF and problem was solved, she ran like a champ after that. Hope this helps.

[oztme]

Interesting. How many kms had you done before the problem showed? How much did they charge for a new MAF sensor (hot film air flow)?

[wallyx5]

Originally Posted by oztme

Interesting. How many kms had you done before the problem showed? How much did they charge for a new MAF sensor (hot film air flow)?

I had around 220,000 miles when I was experiencing that problem. The shop I was working with wanted $440.00 to replace the MAF. I just bought the part and did it myself for $ 204.83. It's not the OEM Bosch part which runs around $365-389.00. I went with a Siemens part from autohausaz.com

[adamjones2000]

UPDATE 3: Stripped off the inlet manifold to clean and complete the swirl flap mod, only to find my manifold has no swirl flaps. Im guessing when the replacement engine went in they used the replacement manifold.

Checked all the vac pipes, all seem fine.

Stripped and cleaned the EGR valve.

Disconnected the MAF and did a test drive to see if any different.

And guess what.............no different. Whats next to try then?

[gercajr]

I had a similar problem of powerloss, after a week of having this problem, the car wouldnt start, i had to take to the shop, it was the Diesel pump that wasnt regulating pressure properly, they replace the pump and fixed the issue, also u may wanna check the pressure sensor first...