Need some help troubleshooting not starting problem
 

Yesterday morning when I tried to start the car, I got only long crank but car wouldn't start. Tried a couple times and I gave up. Car drove perfectly fine a day before.

I thought it would be something simple - either relay or fuse. Checked both and they were good. Then I removed backseat and tested the pump with 12V. Pump ran fine.

Any advise from this point? Car is 08' 4.8i

I'm thinking to loan autozone obd2 tool to pull codes. Anyone knows if their obd2 reader works for 08' X5? Don't know if there is any code.

and the battery is good, right? out of a dozen relays and tens of fuses, which ones did you check?

the autozone code reader can't pull all bmw-specific codes on E53, let alone on a more sophisticated E70... you need a brand-specific software...

i still would go for the battery first...

I checked fuel pump relay and the fuel pump fuses. The battery is still good. Crank was strong.

have you tried to start the car after the initial couple attempts? sometimes the car can start right up after sitting a bit...

did you have any other symptoms before?i understand that the day before it drove fine, but, say a week prior, you might have hit a deep puddle of water.. or, maybe you had a carwash... or, you wanted to test the car's speed limit and took it to 140 MPH... anything comes to mind? or... did you let your wife drive the car????!!!

Yeah,that may be really hard to diagnose remotely,but TerminatorX5 has some good questions.As per experience,always look for a recent repair done to the car.And there is more investigating involved with diagnostics than most people would think.
BTW,if you are close to LA I might be able to help in person.

I just tried to start it again this evening. Same thing.

Didn't notice anything abnormal before and didn't do anything abnormal to the car. :) We did have pouring rain here Sat(I was on highway driving car back home)

Thanks. I wished my autoenginuity would work on this car but it did not. I have bmw enhanced but it could be the outdated software version (7.0.0)

My next diagnosis step is to hook up the fuel pressure test gauge and see if I get enough fuel pressure and see if it's holding pressure.

Is there any sensor that might cause this issue?

There is no sensor for the fuel pressure that may cause a problem.However there is a valve on the fuel rail and if you remove the cap and press the stem very carefully you will at least know if there is a pressure or not.
The in-tank fuel pump is controlled by a EKPM module which varies the voltage to the pump depending on the torque output required from the engine.

the schrader value on fuel rail? I remember seeing one on my E53 before but not sure if I can find it on E70. I'll pull out the plastic cover and check.

I see 2 plugs on this fuel pump. one is the power. I guess the other one is for EKPM module you mention? don't recall seeing 2 connectors on E53.

There must be a schrader for sure.
One connector is for the pump power supply-it comes from EKPM.The other one is for the level sensor.I mentioned the pump control module because if you test and see 7v at the pump ,as an example,that may be normal voltage for idle and low load.