4.8is Cranks over but engine won't start
 

Hey X5 fellows, When I turn the key to start, stater engages, engine cranks (turns) but won't start. Battery is good, only 5 months old. Car has 130k miles. Always premium gas. No computer codes thrown!

Any ideas what to diagnose using process of elimination? :dunno:

Perhaps the fuel pump?

Off the top of my head things to check are,

Fuel pump, key battery/ews, ignition switch, plugged fuel filter, DME module.

And the relays/fuses for them as well.

Key battery/ews would be my first checks. Scan with a good reader and it will tell you if you have ews faults. That's how I diagnosed my wife's e83 long crank/no start issues... dying battery in the key.

Then fuel pump. Then maybe ignition switch.

Even if the key fob operates the doors, alarm, and everything else fine, it could still be key batt? or would good key operation rule this out?

Yep, other key operations could be fine but EWS ring might not be getting enough signal from it. That's what was so puzzling about the X3's no start. Took a scan with Carly BMW app to get an EWS error that made it make sense.

The battery in the key FOB has nothing to do with the EWS system. There's a chip in the key fob that allows the EWS to recognize the key and enable the starter.

The fact that the engine is cranking is proof that it is not a EWS issue. More likely a dead fuel pump. You can have some one listen with the gas cap off while you do a key on and key off to see if they can hear the fuel pump priming the lines, or you can connect a fuel pressure gauge to the fuel rail and see if ypou have any pressure at the fuel rail.

Last resort will be to give it a shot of starting fluid to see if the engine fire. If the engine fire you have a fuel delivery issue.

Could also be a no spark issue. You can pull one of the coil and insert a new spark plug into the coil and observe if there's a spark. No spark mean you could have a bad CPS (crank position sensor).

The battery in the key fob has nothing to do with the EWS. The engine cranks so you don't have a EWS issue.

there's a crank sensor that tells the car the motor is turning. if it's failed the car wont start. probably the problem. i forget what its called but its a little sensor. i replaced on my first X, and just on my brothers Jeep. no code thrown on either car.

Hmmm... I'll have to look into that then. Could have sworn EWS just disabled the spark or the fuel. I seem to remember getting multiple cars with EWS issues that would continuously crank with no start. Maybe I'll have to check out my wife's fuel pump then...