Trouble Starting 05 4.4

[bhennrich]

My wife drove the (2005 4.4i) X5 as she normally does today and got home from work around 1PM as she needed to go back in this evening. At 7PM so 6 hours of sitting, the X was cranking like crazy when the key was turned but would not start. She says she tried 3 times then jumped into the E36 and took off. I went and tried to start it with the same symptoms. On my third try I just kept modulating the gas pedal and it started up on the 4th or 5th press of the pedal. Not sure why. Just trying to start checking. With the throttle by wire I know it is most likely not as simple. Checked all fluids and don't have anything odd happening there. I have started it three times in the last hour with NO issues. It is presenting like a lack of fuel but I really don't know. I truly do not want to just start chucking parts at it. Thanks for any input.

[andrewwynn]

This is the typical symptom of a bum fuel pump. You get a non start when the pump lands on a dead commutator bar.

Random wiggles cause it to move just enough to get to a good spot and it will fire up.

I teach the method of starting of turning the key to the “on” position and wait for the fuel pump hum to stop before cranking. It takes less than six seconds.

If you don’t hear the hum, pump isn’t working. Listen close, Turn the fan down to lowest spot to learn what to listen for.

You can also test the fuel pressure at the fuel rail under the plastic noise shield under the hood.

[andrewwynn]

People will often get a few more drivers out of a dead pump by tapping on the fuel tank to vibrate the pump into a better spot. You probably just shook the car as pumping the gas pedal week do nothing on a fly by wire throttle I would bet.

[zukgod1]

I would check fuel pressure.
Had a very similar issue with mine.
Next drive out (my son took it) it left him stranded on the side of the freeway.
You can check for pending codes but I don't think it would show anything yet.

Sent from my Pixel 2 XL using Tapatalk

[upallnight]

Originally Posted by zukgod1

I would check fuel pressure.
Had a very similar issue with mine.
Next drive out (my son took it) it left him stranded on the side of the freeway.
You can check for pending codes but I don't think it would show anything yet.

Sent from my Pixel 2 XL using Tapatalk

Nope a bad fuel pump will not show any type of codes. But if you have an oscilloscope or a pico scope you can test the fuel pump and determine if it is bad before throwing parts at it. But then you will need to have a oscilloscope and know how to use one. Just like Eric O from south main auto (not a sponsor).

https://www.youtube.com/watch?v=yfa01FFCsUQ