Won't Start in Cold Weather
 

I'm having problems with starting in cold weather.

I have replaced battery and new glow plugs have been fitted. It only happens when trying to start in cold weather.

I am worried I may have sent a spike through the electrics as had to jump start a few times when the battery was low after coming back from a 4 week vacation.

I have taken it to a diesel diagnostic garage who said there was no error codes and the pressure in the rail is fine. They said it may be the fuel pump. But why would this only stop working in cold weather.

I have read in this forum that it could be the fuel pump relay - would this cause the ECU to prevent starting in cold weather?

Any advice is appeciated.

I'm confused. if they said pressure to fuel rail is fine, why they suggested fuel pump might be the cause?

Did you replace the battery, before your 4 week trip? or after?

Exactly...

how the relay for the glow plugs??

do you have a block heater?

Did you replace the battery, before your 4 week trip? or after?

After my trip. Infact, I just replaced it in December. From September to December it started fine after jump starting it. Then it started playing up in December and I had to jump start again. I then decided to buy a battery.

I'm confused. if they said pressure to fuel rail is fine, why they suggested fuel pump might be the cause?

They actually could not replicate the problem. The weather was about 10C.
When I picked it up it started fine.

Now it won't start again they are saying a fuel pump. Does that sound correct? Maybe now that it won't start they will see the pressure is not getting high enough when the fuel is cold.

how the relay for the glow plugs??

I'm clutching a straws - I saw the last thread on http://www.bmwland.co.uk/talker/viewtopic.php?t=64944 & the problem was solved by cleaning/replacing the fuel pump relay.

BTW: Its 2004 with 40K miles. I've owned it for 2 years and last winter it was fine.

How cold is it when it won't start? Is it cold enough for the fuel to gel?

I don't think so - it happens from +1C. It will probably start after much cranking at this temperature, but anything lower it won't. It just keeps cranking and I don't want to kill the new battery.

I'm in the UK so it never gets colder than -4C.

Other mechanics I have contacted did mention that the fuel pump might be too weak to pump diesel gel.

That would explain why when its warm it starts like there was never a problem.

yes it does! just doesn't in London.

Resolved
 

Just wanted to update this thread by noting it was resolved by replacing the fuel pump. There was so much sediment in it that when it was cold it froze and the fuel couldn't get through.

Thanks for the replies except stiggypete. Its a dour scot thing where they are affected by the Scottish Curse Urban Dictionary: scottish curse

Stiggy - by the looks of your icon I doubt it is #1