No start

2002 BMW X5
160,000 MILES • 3.0L • 6 CYL • 4WD • AUTOMATIC
Avatar
ANTIKYTHERA
  • MEMBER
  • 1 POST
Working on the car listed above. would low fuel pressure replace the fuel filter in the fuel pump restoring the pressure but still won't start. Check the timing chain it's intact and still rotating the cam. Did a compression test not get any more than 30 to 60 PSI on any cylinder.my question is is I've heard some of these engines are notorious for the oil pump sprocket bolt falling off would low oil pressure cause a hydraulic lifter to collapse preventing the valves from opening and closing causing low compression?
Jun 21, 2019 at 9:17 AM
Advertisement
Avatar
KASEKENNY
  • ✓Experienced Mechanic
  • 18,907 POSTS
Hi,

Low compression does seem like it is your issue on this M54 engine. However, I have not seen the oil pump sprocket falling off causing low pressure then a lifter issue, then a no start due low compression. Normally, that gear doesn't fall off all of a sudden. The nut normally comes off and the engine starts running very poorly due to low oil pressure causing lifter issue.

Has the vehicle been sitting a while or not run in a little while?

Here is a video of a more common cause of low compression on these engines:

https://youtu.be/NtsKiKWeoa0

If this is not your issue then you will need to run a leak down test to try to determine if the engine is sealing and if not, where you are loosing your compression.

Here is a picture of how the nut will fall off the oil pump gear.

Let me know what you turn up with this video or the leak down test and we can go from there.
Image (Click to enlarge)
Attached Media
Jun 21, 2019 at 10:10 AM
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle