I am getting this code. Lean bank one. Replaced fuel filter and fuel pump. Fuel sender to gauge is bad anyway. No mods to engine.

Car hesitates starting no matter what the temp is.

Thoughts?

 

Going to move this to the Stock Problems/Issues area.

Both P0171 (lean) and P0172 (rich) deals with read outs from the fuel system, canister load, MAF, stability control, engine speed, coolant temperature and ambient temperature. Have you done any research on the code? Are you able to reset the code?

 

I did clear the code. Still hesitates. The code is reminiscent of a BAD MAF. However, the cooper does not utilize a MAF system. It uses MAP.

 

I have a Mini document that provides the technical settings for the sensors relative to different codes. On P0171 and P0172 the Secondary Parameter Enable Value for the "MAF" is 2.22 g/s. Car might use a MAP but the ECU is looking for a MAF.

 

My P0171 code is very intermittent. However, the car starts up sluggish upon turning the key. After a few seconds, it'll idle perfect.

I checked fuel fuel pressure on the rail while idling and it is about 50psi. I turn off the engine and wait about an hour. Check pressure in the rail and it is zero psi!

Since it runs fine but starts up sluggish, I figured it is the pressure regulator built into the fuel filter housing is bad. I replaced that whole assembly and now, the car starts right up and idle fine.

 

Nicely done.

 

Awesome, most of the time it that fuel pump itself which you will not hear that buzzing when you turn the key on. No separate part for that piece just the whole unit.