My 2006 X3 fails to start all of a sudden

My 2006 X3 runs well all the time until today. 3 days ago was my last time happy use. The car was parked in garage. This morning, however, when I turned the ignition key, I only hear the starter kept cranking, the engine fails to start. I checked the battery voltage and charged it to 100% using a battery charger. I also tested the battery using a battery tester. Nothing on the battery seems wrong.

So far I can be sure on the following 2 things:
1) Starter is good, it cranks the engine
2) Battery is good

According to my limited car care knowledge, the left suspect of possible faulty part would be
1) ignition coil
2) spark plug
3) ignition wire
4) ?

I do recall that before this complete failure event, sometimes when I start the car the starter cranked several seconds longer than usual before the engine start to run. Will this helps to indicate which part might be at fault?

For my knowledge (please correct me if I am wrong), this car has no central igniter nor distribution cap nor rotor. the ignition is direct build-in with each of 6 ignition coils to the spark plugs and controlled by onboard computer.

Please help me with further diagnostic advice for this trouble shooting.

Thanks in advance

Where are you located? I'm a BMW master tech located in Long Island, PM me if you're intetested

A dead fuel pump would also cause it to not start. They go quickly with little warning in my experience too. One day you are driving just fine, then when you stop, it won't start and you are in for a flatbedding to the wrench for a new pump.

I'd bet money on it bring the fuel pump. Its located under the rear passenger side seat. As a quick temporary fix, you can open the access door and tap on the top of the white fuel pump with a broom stick or something like that. It may start and be enough to get you home. New fuel pump is around 290.

Originally Posted by mlukas161

I'd bet money on it bring the fuel pump. Its located under the rear passenger side seat. As a quick temporary fix, you can open the access door and tap on the top of the white fuel pump with a broom stick or something like that. It may start and be enough to get you home. New fuel pump is around 290.

Thanks for the suggestion. Thank God last time I drove home and parked the car in the garage. then next time it becomes complete dead without any warning. I would like to try your method, the problem is, my garage side clearance is very tight, I may not even be able to jack up the car.

Any further diagnose steps to test and to make sure it's fuel pump at fault before spending 290 to replace the pump?

Thanks again

Originally Posted by harryhan

Any further diagnose steps to test and to make sure it's fuel pump at fault before spending 290 to replace the pump?

Could be any number of engine management sensors that have died and caused a no start condition.

Such as the throttle position sensor, crank angle sensor, temperature sensor, etc.

That's where someone like bmwoem1 on Long Is. would know immediately what to test.

Are you used to hearing the fuel pump priming when first turning the ignition on?
If now complete silence, that's a useful clue.
If the fuel pump was working O.K. I would think after repeated cranking w/o a start you might smell unburnt fuel.
Not sure, but if there is not a whiff, that does tend to point the finger at the fuel pump.
In case it had been drawing to much power earlier and blew a fuse, it's worth checking the fuse panel at the back of the glove box.
Looks like fuse no. 34 and 54.
But if one was blown you'd want to find out why as a replacement might blow immediately.

You guys are on the right track... I would first pull faults (w/ a BMW scanner). Then I would check fuel pressure at the injector rail (you need a specialized tester).

Originally Posted by Supercourse

Could be any number of engine management sensors that have died and caused a no start condition.

Such as the throttle position sensor, crank angle sensor, temperature sensor, etc.

That's where someone like bmwoem1 on Long Is. would know immediately what to test.

Are you used to hearing the fuel pump priming when first turning the ignition on?
If now complete silence, that's a useful clue.
If the fuel pump was working O.K. I would think after repeated cranking w/o a start you might smell unburnt fuel.
Not sure, but if there is not a whiff, that does tend to point the finger at the fuel pump.
In case it had been drawing to much power earlier and blew a fuse, it's worth checking the fuse panel at the back of the glove box.
Looks like fuse no. 34 and 54.
But if one was blown you'd want to find out why as a replacement might blow immediately.

Thanks a lot.
I do hear the hiss on fuel tank opening in the first a few seconds when the ignition key is turned to "on" (but not crank) position. The hiss will then stop. If I immediately turn the key to "on" again, I wouldn't hear hiss. If I wait for a minute then turn the key "on" again, I will hear hiss for another a few seconds, then hiss will stop. I also checked fuse 35 and 54, both are good. it seems that I can eliminate fuel pump faulty possibility, isn't it?

So what should I do next? I guess it is to check ignition coil and spark plugs. Or something else?

Please advise.