Missfire and stalling

[Longun]

Hi All,

I've got an issue with the M5. It won't idle or drive. The only codes I've had recently are high pressure fuel system low pressure. I've ran some ISTA+ tests and it passes the fuel system but it still feels like its running out of fuel. It could be an injector but I've not got any smoke so not sure on that.

Attached are some readings from the DME's. The pressure looks low to me but I've got nothing to compare it about.

Oddly if I unplug either of the HPFP it throws a drivetrain warning but the idle cleans up. I get no drivetrain error with when both pumps are connected.

Any thoughts on what other tests I can run or where to look next. I'm leaning towards the low pressure pump but the pressures look ok on that.

[M5Rick]

What fuel did you use, with these thunderstorms and prolonged heavy rain there's risk of water in gas station fuel tanks and if it came on after you gassed up then always a possibility as crazy as it sounds..

[Longun]

I was at half a tank when it happened. Did a 150 mile drive for work and it failed about 40 miles into the return journey. This fill up was Tesco 99. Decent thought but don't think it'd be that in this instance.

This happened last week I've only just got around to getting proper BMW diags on my at home, which I thought would help, but then I realised I don't know what the results are telling me

[KurtsM5]

When my lpfp crapped out I got hpfp codes.

[Longun]

Originally Posted by KurtsM5

When my lpfp crapped out I got hpfp codes.

I was certain this was going to be the cause but its showing 85+ psi on diags. I think the good range is 60-75 so its a bit high.

Both HPFP are showing what I think are low numbers but the chance of both failing at the same time I'd thought was slim so I'm still thinking fuel delivery to the HPFP.

I'm still not certain if my car has a fuel filter so going to get under the car and see if I can see one as I'm wondering if I've got a block (Hence higher pressure on the LPFP) than it should be.

[KurtsM5]

I think UK cars are different than US, US cars have the filter built into the lpfp.Have to replace the whole pump.

[KurtsM5]

Originally Posted by KurtsM5

I think UK cars are different than US, US cars have the filter built into the lpfp.Have to replace the whole pump.

And of course, since the lpfp is in the tank under the back seat, I had just filled the car up. So I had both hands(and my face) in gas for a couple hours. When I got the pump out, I couldn't even see thru the filter as it was full of black crap.