E39 M5 - pinking???

[Murdock]

Greeting,

My father brought this to my attention, as he seems almost certain that his M5 is pinking say, for instance, under throttle openings at low revs. I brought it out for a spin myself and managed to hear the noise (a kind of crackling, for want of a better description) he was talking about. Does anyone have any idea what it could be? And if it is, indeed pinking what should be done to rectify it? It's running on 98 so I'm assuming it isn't a fuel quality issue. Cheers.

[Vixpy1]

It will prob be one of the air flow meters. They do fail causing the engine to run lean and pink.

[LittleBro]

Mine used to have a more noticable pinking when it wasnt being fed on Super Unleaded.

[Murdock]

Cheers guys. My mother did fill it with 95 one day, which apparently exacerbated the problem. But I reckon you could be correct with the air flow sensor diagnosis - cheers Dr Vixpy.