Hey guys, so I recently noticed that my 535i has a slight stutter or hesitation when in WOT. It feels almost like a missfire, but it happens for a fraction of a second and it hasn't thrown a code yet. I looked at the logs in mhd and it looks like my fuel pressure drops off ~4-5 psi right around when it happens. I'm curious whether it could be related to the fuel pump, injectors, or plugs/coils. I'm running mhd 2+ with ngk95770 plugs gapped to .022 along with bimmerlife coils. If anyone has any insight into it please lmk but if its the hpfp save me the heartache because I don't want to deal with the stealership

 

I have a 530I 2007 version with 125000 kms on it. I have similar issue with dead spot at low rpms. Car does not stop or stall. It just hesitates for a moment and then kicks off to normal speed. I can replicate this in Parking and Neutral mode too. When you accelerate, it struggles a bit and then goes to normal.

Changed everything I could.

Oil Separator
MAF sensor
hose pipes
non return valves
new coils
new plugs
new radiator fan (old one had an issue)
New fuel pump
New fuel filter
Engine oil and filter changed
Transmission valve body changed with new solenoids
Convertor reconditioned
Transmission oil changed to ZF

Cleaned the vanos, DISA, throttle body too. All looks fine.

Did a throttle learning and adaptation reset, quite a few times. Whenever I do it, the car runs fine for 200 to 300 kms and the problem comes back. I take it again to the mechanic to do the reset and the problem goes away for some distance and back again. What do I have to change?

Disa Valve - intake and outlet (there are 2)
Cam shaft sensor
Actuator Motor
Vacuum pump
Throttle body with sensor
Vanos - 2 no's

These are the only things in the engine area that might need a change.

Please advise.

Thank you.

Arjun

 

have you guys walnut blasted? needs to be done every 50k or so

 

Does it happen at a certain rpm or certain throttle position. I remember one of my old teachers talking me about the pedal position sensor going bad. Not sure if it's any help but something to look into.