[MBurns]

Hi,
I’ve had my 2001 530d for over 4 years now and haven’t had any problems until a few months back then the diesel in the tank went below ¼ full but was still well above the point where the light comes on. Anyway I stopped at a junction and when driving out on the road again the engine stopped and the DDE light came on. I tried to restart to no avail so I ended up putting 5 litres of diesel in the tank and the car eventually started. Since that I’ve noticed that if the car goes under ¼ full, the engine can just quit as above, yet the low fuel light is not on. A few days ago I was driving on a motorway with the cruise control set at 120km/h, with the tank just under ¼ full when the engine stopped. I pulled over and just tried to restart. After cranking for around 15 -20 second the engine started. I revved it hard and then drove off. After around 1 minute it stopped again. On restarting this time I decided to keep the speed low at around 80km/h and it ran well enough for me to get to a filling station. After filling up with diesel, the engine still took around 20 second to start but has been fine since, once fuel level is above ¼. I don’t think it’s a faulty tank level sensor as the tank range is the same as it always has been to the ¼ full mark. Sorry about the long winded description but I feel the more information I can give the easier it might be to locate the problem.
Thanks in advance for any help.

 

[witeshark]

I think I'd start with the fuel filter and the pump(s).

 

[marti5]

Hard one......It may well be you HP pump, which is situated under the bonnet, should be easy to find follow the injector feed back .....you will end up at the hp pump.

 

[DonJ]

That to me would sound like something faulty with the level sending unit.

 

[[email protected]]

Hi,
I’ve had my 2001 530d for over 4 years now and haven’t had any problems until a few months back then the diesel in the tank went below ¼ full but was still well above the point where the light comes on. Anyway I stopped at a junction and when driving out on the road again the engine stopped and the DDE light came on. I tried to restart to no avail so I ended up putting 5 litres of diesel in the tank and the car eventually started. Since that I’ve noticed that if the car goes under ¼ full, the engine can just quit as above, yet the low fuel light is not on. A few days ago I was driving on a motorway with the cruise control set at 120km/h, with the tank just under ¼ full when the engine stopped. I pulled over and just tried to restart. After cranking for around 15 -20 second the engine started. I revved it hard and then drove off. After around 1 minute it stopped again. On restarting this time I decided to keep the speed low at around 80km/h and it ran well enough for me to get to a filling station. After filling up with diesel, the engine still took around 20 second to start but has been fine since, once fuel level is above ¼. I don’t think it’s a faulty tank level sensor as the tank range is the same as it always has been to the ¼ full mark. Sorry about the long winded description but I feel the more information I can give the easier it might be to locate the problem.
Thanks in advance for any help.

I have exactly the same problem and the fuel pump in the tank has been replaced but did not solve the problem. Have you been able to find an answer?

 

[MBurns]

I have exactly the same problem and the fuel pump in the tank has been replaced but did not solve the problem. Have you been able to find an answer?

Hi Robin,

It’s good to find someone else who has the same problem. Thanks everybody else who has responded also. Anyway I haven’t done anything with it yet other than have a look around the injectors for leaks, which was mentioned somewhere, though I can’t see how this could be the problem. Anyway there were no visible leaks there. My first task will be to change the fuel filter and if this doesn’t work I was looking to the fuel pump in the tank. However it’s interesting to note that this didn’t do anything for you. It seems to me like the thing is somehow sucking air!? But I don’t think there is anywhere for the air to get in unless a pipe was corroded or something. Sorry for going on but I’m just thinking out loud right now. Have you noticed whether your car hesitates sometimes when giving it welly? I’ve noticed this and it seems like the traction control is holding it back but presumed this was not the case as the road was not slippery and I didn’t notice the light flashing either (not that I was watching it). I didn’t notice though at what level the tank was at. When you changed the pump I presume the filter was also changed?

 

[MADDOUG]

Have a check of a parts drawing and look to see if the in tank pump has an 'o' ring that locks it in to a cradle or mounting device.

This is a common e34 tds fault at a 1/4 tank,google 'lift pump 'o' ring .

 

[[email protected]]

Hi Robin,

It’s good to find someone else who has the same problem. Thanks everybody else who has responded also. Anyway I haven’t done anything with it yet other than have a look around the injectors for leaks, which was mentioned somewhere, though I can’t see how this could be the problem. Anyway there were no visible leaks there. My first task will be to change the fuel filter and if this doesn’t work I was looking to the fuel pump in the tank. However it’s interesting to note that this didn’t do anything for you. It seems to me like the thing is somehow sucking air!? But I don’t think there is anywhere for the air to get in unless a pipe was corroded or something. Sorry for going on but I’m just thinking out loud right now. Have you noticed whether your car hesitates sometimes when giving it welly? I’ve noticed this and it seems like the traction control is holding it back but presumed this was not the case as the road was not slippery and I didn’t notice the light flashing either (not that I was watching it). I didn’t notice though at what level the tank was at. When you changed the pump I presume the filter was also changed?

Yes filter all changed and mechanic has now spent a full day chasing everything through but primary tank is empty and the secondary tank wont fill it although the pump is new and so on. When the primary tank is filled all goes very well so I dont think it can be anything wrong with the pump on the engine. No other problems , goes just fine in normal conditions and all the diagnostic checks seem OK.
A mystery!

 

[[email protected]]

Have a check of a parts drawing and look to see if the in tank pump has an 'o' ring that locks it in to a cradle or mounting device.

This is a common e34 tds fault at a 1/4 tank,google 'lift pump 'o' ring .

Thanks for your help. This is an E60 dont know if that matters? Now fails at 1/2 when the primary tank is empty and the secondary fails to transfer across despite new pump and all the pipes etc checking out. Pump is running but not sucking up fuel.

 

[witeshark]

Could it be air in the system?

 

[MBurns]

Ok, I think I might have found what’s wrong with it. I realised that there are actually three pumps on the car. One in the tank, one inline pump behind the front left wheel and the high pressure pump that supplies diesel to the injectors. I’m not sure of the exact location of the tank pump on the E60 but I’d imagine the setup is similar. On mine anyway the tank pump is on the right side of the tank. I pulled out the back seat and located the plug to the pump. This plug has 4 pins. I checked if there was power at the plug and there was, so then I tried connecting 12V directly to the connection on the top of the tank. The two connections are the ones relating to the largest size of wire. Connecting this up directly did nothing at all. So I’m now 99% sure that the problem is the pump in the tank. So I’ll be picking up a new one tomorrow and I’ll let you know how it goes. To be honest the symptoms now make sense as without this pump working the inline pump will be unable to deliver diesel once the tank goes below a certain level as cavitation will most likely occur before the inline pump and result in air being fed to the engine. Also I had noticed that the power didn’t quite seem to be there like it used to be. Anyway I’ll post my results tomorrow.

 

[MBurns]

I got my tank pump today and fitted it this evening. I double checked the old one and it was definitely faulty and not running at all. I also changed the fuel filter. On taking the car for a drive afterwards I can say it feels to be going the way it should and all the power is back. The tank is now at around ¼ full and I’ve got some short trips to make tomorrow which should allow me to determine if it is ok when closer to reserve. I’ll keep a can of diesel in the boot in the meantime, just in case. So I shall report my findings back here again tomorrow.

 

[witeshark]

Seems like good progress!

 

[MBurns]

I can now report that this problem is now 100% solved. I drove the car today until the low fuel light came on with no problems at all. I would like to thank everyone who commented on this thread. Although it might not seem like we might be going in the right direction all the time, I found that by researching suggestions by others actually led me to find other information. Once again thank you all.