2009 116i Hesitation/ Start/ Stop Light Flashing

[DKS]

Hi all,
My brother has a 59 plate 116i Sport which has developed an annoying issue. Once a bit warm, say 10 mins driving, it will start to hesitate, like a misfire. I replaced the plugs and coils about 2 year ago after a similar incident. The difference this time is that the start/ stop light flashes in time with the misfire.
The car has 2 codes for sulphured cat and low pressure pump, but *no* fault light on the dash. After a bit of research a lot of forums say give it a thrash to clear the cat (he doesn't do many long trips). We tried a run at 5k for a few mins which really upset it and the start/ stop light flashed continuously and it lost a lot of power, wouldn't go over 50mph. Went back to random misfires after a restart. Interestingly when we stopped in order to restart, that engine stopped itself which is the first time I've ever seen it do that in the 4 years he's had it.

I'm not too experienced with BMWs, anyone got advice from a similar problem?

TIA

Edited by DKS on Wednesday 20th March 13:41

[d_a_n1979]

DKS said:

Hi all,
My brother has a 59 plate 116i Sport which has developed an annoying issue. Once a bit warm, say 10 mins driving, it will start to hesitate, like a misfire. I replaced the plugs and coils about 2 year ago after a similar incident. The difference this time is that the start/ stop light flashes in time with the misfire.
The car has 2 codes for sulphured cat and low pressure pump, but *no* fault light on the dash. After a bit of research a lot of forums say give it a thrash to clear the cat (he doesn't do many long trips). We tried a run at 5k for a few mins which really upset it and the start/ stop light flashed continuously and it lost a lot of power, wouldn't go over 50mph. Went back to random misfires after a restart. Interestingly when we stopped in order to restart, that engine stopped itself which is the first time I've ever seen it do that in the 4 years he's had it.

I'm not too experienced with BMWs, anyone got advice from a similar problem?

TIA

Edited by DKS on Wednesday 20th March 13:41

Ideally you need to get it plugged into proper diagnostics first (ISTA ideally); but the likes of Bimmercode/Bimmerlink/Carly for BMW will work well too

See what the codes read again and go from there

To me it sounds like a fuelling issue; but it could be all sorts

[DKS]

Thanks, yes we'll probably try and get a proper code reading (we bought a basic tool to program a new battery and it did pull those two codes).
I guess I'm hoping for a reason as to why the stop/ start light is flashing and no ECU/ fault light.

My initial thought might be a duff crank sensor making the ECU think the engine has been stalled. Wild guess.

[steve_n]

Sounds like the low pressure fuel pump not delivering enough fuel/inconsistent feed.

I've just changed the LPFP inside the fuel tank on my 2011 F11 535i. It didn't have symptoms anything like as bad but it'd sometimes have a rev drop or slight hiccup at idle. Also, the engine was shaking like a misfire at around 2.5krpm. I know the electrics are good, it's had new coils, plugs and injectors. Now the idle is rock solid and the shaking is gone.

Given the LPFP isn't that expensive it's worth a shot.

[DKS]

Thanks. Where did you get yours from?

[steve_n]

DKS said:

Thanks. Where did you get yours from?

I bought a Pierburg one from Autodoc. If you see this in time and order before 11pm then the prices are currently as cheap as they get. Monday is usually a good day for Autodoc discount.