Limp mode etc

[Smuggling Sam]

Help required, please. I have had this car(BMW 325i 2007) for just over a month and have EML on and it goes into limp mode. It has been into a BMW dealership, plugged in with the errors as in the photo. I have bunged a number of bottles of BMW’s own fuel/engine/injector cleaner in and still have the same problem. Is it likely to be the fuel pump or is it summat else? It seems to be fine for a week but that is after a bottle of gloop and 97 fuel, I’m not sure I can continue to fund a car with cr@p fuel economy drinking the expensive stuff! If anyone has had any experience of this and what might be a possible cure, I will be in your debt
TIA

[helix402]

Probably a faulty hpfp. Didn’t the dealer diagnose it?

[Smuggling Sam]

They did suggest it but weren’t that convincing stating that they would need to do the full diagnostic in order to confirm.

[RUSSELLM]

What’s a “full diagnostic” as opposed to what they’ve done by reading the DTC’s ?

[bmwmike]

early n53?

edit didnt notice the engine showing in the screenshot. This error can be caused by a faulty fuel pressure sensor. bimmerprofs website has a lot of info on this.

I wouldnt ever bother with bmw dealer for this engine btw. Leave them to do discs and pads and maybe diesel timing chains. Complex stuff like diagnosis is better done by someone who knows the engine.

Edited by bmwmike on Saturday 19th December 11:04

[Smiljan]

RUSSELLM said:

What’s a “full diagnostic” as opposed to what they’ve done by reading the DTC’s ?

You really can’t diagnose a fault from the DTC alone, live data, wiring checks, etc. Etc.

For a car this age personally I’d be finding a local specialist to take a proper look rather than just reading fault codes and firing random parts at it.

Fuel pressure out of expected range so check live data both at idle and under load, if readings confirmed then need to determine if it’s pressure sensor fault (quite common) or pump fault or wiring from sensor etc..

Edited by Smiljan on Friday 18th December 23:48

[Zygersaf]

Had similar issues with my N54, if you are in limp mode and moving, I believe it is not necessarily the HPFP, not sure if you engine has both HP and LPFP but for me it was the low pressure side, was not providing the high pressure with enough fuel, and therefore I was getting HPFP error codes but still moving...sort of.

Check out a youtube channel called Vehicular DIY and his fuel pump diagnosis videos, really useful shows you what to look for on logs and gives explanations on symptoms of sensors vs pumps.

[Smuggling Sam]

Thanks for your responses folks. Dealer trip was a health check and, given they weren’t more help, the Indy will get the work; it was more about getting some ideas before bunging a raft of new bits on it. It’s going in on Monday for a look at and hopefully, we’ll find the problem. I’ll post results as and when it’s sorted.