2006 X5 Diesel intermittent cold start problem
 

Hi guys!

Well I´ve understood I´m not the only one with X5 start problems...
Never had any problems with my car, but a couple of weeks ago I started having problems starting it. It seems that the colder it gets outside the more pronounced the problem is. Here´s what happens:
I turn the key and all is fine. Everything lights up as usual and the DDE light indicates glowing. Then starter cranks just fine but there is no sign of ignition. I then have to completely turn the ignition off and try many more times before the engine suddenly fires.
I notice that every time the engine fires there is an extra pump buzzing sound when I engage the ignition. Hence it appears that the diesel pump fails to function every now and then. But what causes this? My car is at an official BMW dealer as we speak but they haven´t been able to recreate the problem and have no clues. The outside temperature is of course much higher now, so the problem doesn´t show up. Needless to say I´m getting a bit frustrated. Any ideas much appreciated!!:thumbup:

[QUOTE=opienor;812122]Hi guys!

.................. the DDE light indicates glowing. QUOTE]

Whats the outside temperature when this happens?Does the glow plugs light stay on while you are cranking ?
Do you have any error codes?
From a mechanical side,they shoud be looking at glow plugs first,injectors and then they should check the fuel pump pressure.

From an electrical side,they should check the crank sensor,fuel rail pressure sensor .

Thanks powers1!

The problem gradually intensifies as outside temperatures drop. Lower temps equal more start attempts. Worst case happended at -4 deg. Fahrenheit when the engine just wouldn´t start at all and the car had to be towed. I´d say the problem appears between approx. -4 to 23 degrees F.
I think you may be right about this being some sort of a sensor or electronics related problem. Especially since I can clearly hear that the fuel pump fails to activate the times the car doesn´t start. Something appears to be wrong in the startup sequence. I glow, fail to hear the pump, crank with no start. This is repeated a number of times until the pump (I assume) suddenly comes to life when ignition is activated, the glow light goes out and voila the engine starts. I have tried to go from off to ignition without cranking a number of times to see if the pump suddenly starts, but without any luck. The cranking (without start) somehow seems to "wake up" the pump for the next start attempt.
The glow indicator lights up and then goes out before I start cranking. Everything appears normal in that department. And no error codes I´m afraid.

Well,its when you dont get the error codes ,and the engine doesnt start,that the hard work starts:(
Have you tried waiting 25 secs before cranking the engine?This is about the time the glow plugs take to turn off and will give you more heat to burn the diesel and start the car.
The coolant sensor is also influencial in the start procedure,so get them to have a look at that.
Another thing is if your EGR valve is closed ,it wont allow air into your engine and it will starve and wont start.To test it,You can pull off the vacuum pipe to it and see if it makes a difference.
The best way and we do here is we do it by trial and error,by replacing the sensors I mentioned above.
Today ,we had a 330d E60 that wouldnt go above 2500 rpm when the engine coolant temp (ECT) was between 10-50 degrees...!After this temp, it was fine!No error codes !We replaced the obvious sensors...nothing!Tried the turbo solenoid and voilá...all good...:dunno:
I leave you here a pic of all the sensors in the engine compartment.

Haven´t tried that but will do. Does this glow period change with temperature or is it a standard 25 secs regardless? I didn´t know the glowing lasted that long. Always thought glowing stopped when light goes out. Thanks for teaching:thumbup:
With temps going way below zero F here in Norway during winter most diesel cars have a hard time every now and then. Mostly caused by dirty, clogged up and frozen fuel filters. Initially thought to be the problem with my car, but no.
The BMW guys continue their little investigation on my car tomorrow so crossing my fingers they will discover the reason. In the mean time my trusty 318i runs like a clock:cool:

Thanks a lot for taking the time powers1

Its not temperature related!Glow plugs go out when the Glow plug module switches off (about 25 secs) or when you crank the engine,whichever happens first.
Normally,when the plugs are going faulty,letting them be on for a few more secs,helps them heat-up more.This is also a sign that they need changing as they are either taking longer to heat-up or you have a faulty plug(s).
In anycase ,in extreme below freezing temperatures,its always best to wait a few more secs,before you crank it, after the glow plug light goes out.
Above freezing,they are almost redundant.

I hope the Bmw guys there do their job!
Keep us posted please:thumbup:

So got my car back a few days ago. The mechanics had tried to reproduce the failure to start but it just started and ran like a clock every time. Very strange, although the weather is considerably warmer now so that might be the reason. So no luck on finding the issue.
I´m starting to think there could have been some kind of contamination in the diesel fuel at some point, water that froze or something. Although I can´t see how that would prevent the fuel pump from working during the start sequence.
Oh well just have to wait for next winter and cold weather again to find out I guess. Thanks anyway for trying to help!

Thanks for posting back with feedfback:thumbup:
Although they couldnt replicate the start failure,the important thing is, its now running ok.Lets hope whatever it was it resolved itself and you wont have any more problems:)

So unfortunately I´m back to revive this thread on my 2006 E53 X5. This cold start issue reoccured last winter but didn´t cause too much problems as temperatures were fairly high.
Now winter is back, and so are the problems. Same thing: cranks just fine, but total diesel starvation as the electric feeder pump doesn´t start when engaging the ignition.
Took the car to the mechanics and history repeats itself: car starts like a charm every time (around freezing), glowing works fine, fuel nozzles are fine, battery is fine, no associated error codes. They change the fuel pump relay as it´s a cheap part and could be the issue.
Got the car back yesterday. Today outside temp is -12C and the car doesn´t start. Electric feeder pump kicks in about 1/20 ignition attempts.
So I set out on a little trial and error quest of my own. Suspecting cold/humidity build up in electronic components I use a hairdryer to heat the electronics compartment under the hood up to room temperature. I also give all connections and relays a good "shake" in case there are any bad connections.
After that a new start attempt, but no luck. No feeder pump kicks in.

So I place an electric car heater on top of the engine, close the hood and let the compartment heat up slightly for about 20mins. Still no luck on starting.
As a last resort I move the car heater to the left side of the car (as seen facing forward), blowing hot air downward.
Voila: after a couple minutes the feeder pump now starts up on every ignition attempt. The engine starts at once on several consecutive start attempts.
I don´t know what exact components are located down there on the left, but most noticeable is a square one with five thin metal pipes exiting it forward.

It seems now I may be onto something, but absolutely without knowing exactly what:cool: Not believing my findings I let the engine cool way down again for a couple of hours before repeating this last procedure. Same thing as above: everything works flawlessly after heating the left side for a few minutes.

Any idea what this could be?
This car is now giving me a headache all over again. As much as I love it I´m also getting really frustrated with this issue. It has already this winter ruined one long weekend and several appointments I never got to.

Here is a video of the problem. No buzzing from the electric fuel pump when engaging the ignition. Cranking works fine but engine is totally dried out:

BMW X5 E53 Cold start problem - no start - YouTube

In this second video I have tried starting MANY times (appr. 30) and now sudddenly the electric feeder pump kicks in every time I turn on the ignition. You can hear it buzzing in the background. Engine starts with ease. Today heating the engine compartment seemed to have little or no effect for some reason:

BMW X5 E53 Cold start problem - starting - YouTube

I talked to the dealer today and I´m taking the car back in a week. This time I will let it sit there until the problem is solved. I also sent them these videos.