It won't start! Fuel Supply?

X5Sport · Post by **X5Sport** » Sun Dec 05, 2010 8:37 pm

SWMBO took the E53 (now hers) off to South Wales to see her folks for a few days and has had to come back in a 1.2 Corsa (Stop Laughing ypu lot!

)

Her X5 would not start this morning. It turns over just fine but will not fire. The Breakdown recovery man said he could see no fuel movement in the lines from the tank ( 1/2 full ) and has blamed the immobiliser. Seems a bit odd, but I suppose it's possible. My thoughts are more around the fuel pump and / or fuel filter at the back, or possibly te pressure sensor up front, but has anyone experienced this fault? I don't know what system controls drive what bits. Does the immobilser still allow the starter motor to turn, or is it a fuel cutoff system?

The car is being recovered from Wales to Milton Keynes tomorrow so I expect we'll find out soon enough. Bit of a pain though.

jason@bwchiptune · Post by **jason@bwchiptune** » Sun Dec 05, 2010 11:43 pm

I would 1st try another key in case it the key has loss it's rolling code
You will also need to do a diagnostics to help

phill · Post by **phill** » Mon Dec 06, 2010 8:47 am

Might be possibly the aux fuel pump located in the petrol tank, but I would have thought the fuel would be about just below 1/3 of a tank showing on fuel gauge. The aux fuel pump is the one that pumps fuel from one side of the fuel tank to the other.

The above is only a thought as I would think the car should have been misfiring before. Mine had same problem and misfiring started at about a range of 80miles left in tank.

Phill

pvr · Post by **pvr** » Mon Dec 06, 2010 9:32 am

Not a laughing matter ...

Let me guess - yit was your fault, right?

X5Sport · Post by **X5Sport** » Mon Dec 06, 2010 9:37 am

Thanks for the tips folks - yes we'll try the spare key when the car arrives from Wales.

@Jason - does the immobiliser kill the fuel and allows the starter to work? Just so I know what works with what to stop things happening, or the car being nicked.

@PVR - of course it was my fault, even though I don't drive it and was 250 miles away at the time.

stevox5 · Post by **stevox5** » Mon Dec 06, 2010 6:25 pm

Hi there

Try the key if no luck and you can't see fuel movement in the clear plastic fuel pipe under the bonnet then it's likely it's the pre supply fuel pump located under the floor pan ( under outer splash guard ) as suggested a diagnostic check is a good idea to see if you have pre. Supply pressure to the fuel filter head ( should be 3.5 to 5 bar on cranking,if you find the pump is duff change the relay also as when the pump fails it tends to burn the relay contacts,

Hope this helps

Cheers

Steve

X5Sport · Post by **X5Sport** » Tue Dec 07, 2010 3:02 pm

Tried both keys with no luck. Battery was completely dead and has now been recharged, again with no joy.

Long & Short Diagnostics have been run with no fault codes showing up. Good ere innit!!

4 hours of investigations so far and still a lot of head scratching going on. Could be the DDE Module, or could be wiring somewhere. We're not much further forward at present anyway. I suppose it could even by the keyswitch or frozen fuel lines, or dunno what. Hopefully the investigation work won't go on too much longer as Warranty Direct don't cover that bit. Could be worse as it could be a BMW Deealer doing it at Â£150 an hour, rather than a BMW/Merc Indy at Â£50 an hour.

Looks like the 3er may be back on the road while they try and work out what gives. They did say it might be the swirl flaps, but I said there weren't any on the X5.

I'll suggest fuel pump and relays to them, but I would have expected (forlorn hope maybe) that a fault code would have been generated if that was the case.

X5Sport · Post by **X5Sport** » Tue Dec 07, 2010 8:46 pm

for StevoX5.

Looks like the fuel pre-pump relay may indeed be the beastie. Â£8.51 for The part and Â£240 labour to find and fix it. Ho hum. Shame it doesn't throw a code when it fails though.

SWMBO now says I gave her a duff car........I knew it would end up being my fault somehow...

Hopefully we'll get it back tomorrow (Weds) and all will be well. I think I'll change the battery though coz at 6 years since build it is beginning to show serious signs of wanting to fail completely. I feel a new Bosch Silverline approaching. Now to find one cheap...

CondorX5 · Post by **CondorX5** » Tue Dec 07, 2010 9:35 pm

My 4.8 threw a wobbly very similar to this a few weeks ago before the freezing weather hit - I posted on it as I was so impressed by BMW Emergency Service who got someone out to me in about 20 minutes, and one or two others commented they had had similar issue with no definitive diagnosis when hooked up to diagnostics.......suggestions about battery developing a fault and fuel injectors (discussed on US forum at some length).

Mine also showed no stored faults when the dealer checked it and it hasn't done it since....it turned over continuously without actually starting....

x555 · Post by **x555** » Sun Dec 19, 2010 8:11 am

[quote=""X5Sport""]

for StevoX5.

Looks like the fuel pre-pump relay may indeed be the beastie. Â£8.51 for The part and Â£240 labour to find and fix it. Ho hum. Shame it doesn't throw a code when it fails though.

SWMBO now says I gave her a duff car........I knew it would end up being my fault somehow...

Hopefully we'll get it back tomorrow (Weds) and all will be well. I think I'll change the battery though coz at 6 years since build it is beginning to show serious signs of wanting to fail completely. I feel a new Bosch Silverline approaching. Now to find one cheap...[/quote]

And the verdict was??????

X5Sport · Post by **X5Sport** » Sun Dec 19, 2010 9:17 am

It was indeed the relay. Been replaced and has started perfectly every time since. The battery was stress tested and found to be fine.

I wonder what it is about this particular system design that causes the relay to fail, and why it seems to be much more prevalent in very cold weather? Not having seen the relay and been able to take it to bits I don't know if it's pitted contacts that go high resistance, or the energising coil that fails. Could even be included in the fuel heating circuit, and that is causing a problem, but without a wiring diagram I can't tell. Seems to be a pretty common issue though.

x555 · Post by **x555** » Mon Dec 20, 2010 11:38 am

Thanks for the update

BL02WAS · Post by **BL02WAS** » Mon Dec 20, 2010 4:13 pm

hows the head?? thanks again for that!!

Sent from my iPhone using Tapatalk

x555 · Post by **x555** » Mon Dec 20, 2010 4:25 pm

[quote=""BL02WAS""]hows the head?? thanks again for that!!

Sent from my iPhone using Tapatalk[/quote]

Still rough as rats mate and no worries........bring some cash with you next time and buy a sub enclosure you tight git

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