E39 530d intermittent starting issue / cutting out
Discussion
Got a 2001 E39 530d here. Had it about a week, in that time every now and then it'll cut out. Sometimes it'll start straight back up, other times it'll need to sit 20-30minutes else it just cranks endlessly. Sometimes before it cuts out it'll start running rough and struggling to idle. Symptom wise it looks like a fuelling issue, however when plugged in it ran no codes at all; normally failing fuel pumps would throw a code for low fuel rail pressure. Could it be injectors? I'm baffled by the fact that it hasnt thrown a code...
It's probably 1 of 2 things....
It's the pump under the passage seat on the underbody of the car, 30 minute fix
Cam sensor, 2 minute fix. Cam sensor would normally throw a fault code though.
A tenner says it's the pump, you can sometimes get lucky by stamping on the passenger foot well and it will kick into life
It's the pump under the passage seat on the underbody of the car, 30 minute fix
Cam sensor, 2 minute fix. Cam sensor would normally throw a fault code though.
A tenner says it's the pump, you can sometimes get lucky by stamping on the passenger foot well and it will kick into life
sounds same issue as my 2004 645. It has a wobble every few months. Read loads on the net and it is down to the fuse box needing replacing. A fix round it was to just start it off another car, soon as it had been in contact with another car it was fine again. It hasnt done it for a while. I knew it was coming as the sat nav would start to flash on and off. i still havent fixed it, i just carry some jump leads in the back but touch wood it hasnt been back for nearly a year.
Its had a new fuel filter and pumps seem fine; ran proper diagnostics today, pre supply and rail pressure are about where they should be. Did a leakoff test expecting a few dead injectors but instead they were fine; what we did notice however is the rubber glove used to seal off the return to tank line (which should just operate on a basic vacuum from the tank) started inflating from backpressure! Under the glove was a cap on the t-piece so the pressure was sufficient to blow the cap off and start inflating the glove. No idea what could cause backpressure from tank through return line?? The return line seems to take quite a complex route through to the tank, taking two routes and interchanging with the feed lines presumably through two one-way valves so perhaps they are dead. During the leakoff test with the injectors just leaking off into unsealed bottles, it ran fine; upon reconnecting it ran like a dog again. Then when putting the return line into a bottle, it still ran like crap so it was perhaps a coincidence that it ran better but the return line backpressure is still not a good sign. It also has a mystery vacuum hose disconnected which appears to come from the vacuum chamber under the turbo. It leads to the inlet but is just hanging off not connected to anything so need to figure out where that goes. All in all, good that pump and injectors or fine but I am truly lost now and searching for this issue just brings up stories of people replacing pre-supply pumps or injectors and the issue going away. Very much lost now. Does anyone have a fuel / vacuum diagram for the M57B30 engine?
Does your car have a saddle tank? My touring does and used to suffer from a common 1/4-tank syndrome where it refused to start when the level was low
The pump picks up on one side only uses the venturi effect to pull fuel from the other side of the tank. I replaced the in-tank pump on mine which improved it but I am careful not to let it run too low
Nick Froome
The pump picks up on one side only uses the venturi effect to pull fuel from the other side of the tank. I replaced the in-tank pump on mine which improved it but I am careful not to let it run too low
Nick Froome
It does but the issue comes regardless of fuel level unfortunately. At the end of my tether with it, I'm pretty mechanically competent and have dealt with fuelling issues before on cars, beyond that I've had 4 different people look at it and try and diagnose and none of them have any idea. I've read pretty much every single thread on M57 issues / misfires and nothing seems to have narrowed down the extremely strange symptoms. Beyond that, the ECU will now no longer talk to any code readers. Tried two different ones on two different occasions and they wont communicate at all. Starting to think it could be a fried ECU but being an EWS 3 car with the diamond shaped key a new ECU is not a cheap nor easy solution...
Gassing Station | General Gassing | Top of Page | What's New | My Stuff