Hallo,

i have a big problem, since a few days my car runs sometimes extremly lean under boost.
i made no setup changes before than phenomen appears.

i have the following symphtoms:

the mixture is fine under part throttle until 1000mbar (absolute pressure) (closed loop is turned off)
then the mixture begins to enrich to 13.5:1 (thats also ok) but when i reach 0,2-0,3 Bar of boost the car
leans out dramaticaly to high 14:1's and then there are two options.

When i stay on the throttle sometimes it enriches to 12.5:1 (which is ok) when it reaches full boost (0,6 Bar)
and in the other case (which appears not so often then the first one) it leans out more so i have to
lift off the throttle.

i rechecked the fuelmaps and the complete engine management minimum four times but i can't find any malefunction
i also don't have holes in my fuelmap, the map is very linear and smooth.

now my question: are there ANY possibilities that it is NOT an electronic problem? if yes, what can that be?

please help me, i have no ideas any more.

Greets
Malte.

 

Hi,

i have an additional idea... could it be a broken fuel pressure regulator? (i use the stock one and it has allready 160.000 km)

Greets
Malte.

 

possibility could be the pressure regulator.. i have one i'm selling .... um.. also could be a the fuel filter... when has that been changed last?

 

Oh yes, the fuel filter is also a possibility, i think it was last changed about one or two years ago and the last 6 month the car stood in the garage.

maybe i change the fuel filter and if this has no effect, i try another fuel pressure regulator...

anyone with other things i can check?

i thought that my inline fuelpump has a problem and so blocks the fuel but i think thats not the problem because it makes noises like everytime so it works...

Greets
Malte.

 

I would def try a new FPR, maybe even an aftermarket one, so that youhave the option to raise and lower the pressure.