It sounds like a fuel problem. I would investigate the fuel pump and injectors first. I had an issue with a bad injector that would slowly bleed down when the car was off for several hours. It would drop the fuel pressure and require longer time to start. In cold weather it was worse.

Really a had start issue should not be too hard for the mechanic to diagnose. Once he proves it will start, he knows it has compression, fuel/air and a spark. From there, he just needs to figure out why one of those components is missing at start up.

Check this out:

http://www.xoutpost.com/bmw-sav-foru...tml#post906410

Monitoring fuel pressure during cold start would b the way to test...but most modern BMW techs just 'look for codes'...

Ard,
I think we both cut our teeth working on motors with no electronics. It's amazing how much of the basics have been lost.

Thanks for all the suggestions, my X5 has been at the dealer for a full week now and they still have not diagnosed the problem. On Tuesday, they suggested replacing the fuel pump. Yesterday, they reconsidered and today they are monitoring fuel pressure. The battery is new and was installed by the dealer 10 months ago and they say it is fine. I am driving a loaner 328 but miss the Xman. Will update asap. Thanks again.

Latest word from repair tech..the fuel pressure regulator, which is internal in the fuel pump, is leaking down intermittently and that is causing the extended crank time.

Glad you got it fixed. I do not understand why this took so long to diagnose. There should be a schrader valve on the fuel rail. I would have tested fuel pressure with the vehicle off, then I would have gotten the vehicle running and tested fuel pressure. I do not know the BMW spec; but, I would expect it would be somewhere in the 45-55 lbs range. From there just hit the throttle, see fuel pressure rise 5 or so lbs (this tests pump performance). Pull the vacuum line, again we should see fuel pressure rise 5 lbs or so (this will test the regulator). Turn off the vehicle and wait 30 minutes or so, see how much pressure bled down. It should be nearly no change. Leave it overnight and check the pressure again. If the pressure bled down, you are losing fuel pressure.

A leaky injector will make for a hard start as well as the car running rich on one or more cylinders at start up. You may see black smoke. A bad fuel pressure regulator will allow the fuel to drain back into the tank, so you will not have the rich condition at start up. A quick check of the exhaust at start up and pulling the plugs will tell you.

Sorry for the long reply, it just bothers me that modern techs struggle with the basics. This is something that someone with basic mechanic skills should be able to diagnose.

Thanks very much for your detailed reply, you really know your stuff! Oddly, they havent actually fixed my car yet, I asked if the leaky fuel pressure regulator could be replaced without replacing the fuel pump but haven't gotten any response. Will post again when I hear something.

I enjoy working on anything with a motor. Been playing around with them from my first Rupp mini bike 30+ years ago. :D

I would expect that the pump and regulator are one piece. I would guess that it was a manufacturing decision.

The difficulty with modern diagnosis is more than meets the eye...

While we both said "monitor fuel pressures"...which indeed was the key, there is an economic factor at play.

You see BMWNA only pays the dealer for certain service codes- if a dealer spends 4 hours diagnosing a bad sensor, the "book" may only provide for 30 minutes to diagnose and repair- because the 'book' assumes a code will be set and the car will arrive with a bad sensor code already logged.

So dealers- and specifically the tech and the service manager- really dont like spending time to diagnose stuff that is outside the usual path. They have to document complaints a few times, then send it to BMW...then open a puma..then BMW says 'run these test plans'... all the while, BMW is telling the dealer what they will pay for the work they are asking. Practically speaking, these long drawn out problems are a lot of 'wait for PUMA to reply' then 'find time in the schedule with the other 20 cars I am clearing to do what they ask', then 'document results and send back'...rinse and repeat. BMWNA and PUMA control the work reimbursement and therefore control the pace of this stuff.

I post this so people can understand what motivates/restrains the tech/dealer... the key to managing a repair is to support the dealer when he is doing HIS job, (and kick butt when they arent)..but if you can show them you understand their challenges that are created by BMWNA, you buy some goodwill in the relationship

Not sure this WAS the issue here, but food for thought.

A

haha.

Honda Trail 70. 40 years ago.

Actually working on a pair of them now doing a restore!