Hi, I hope all are well.

The main fuel-pump on my 1985 245ti makes an abnormal loud high-pitched buzz (African killer-bee-like), sometimes almost grinding noise. I'll look into it further when I find the time. The car is new to me, not yet legally on the road but runs mostly well during 'test-runs'.

This evening, though, I laid down besides the parked, running car and pinched the fuel line, along a 12 inches length, just before it goes into the pump. I wanted to see if I could feel air bubbles that might be coming from the in-tank pump (I think I did feel some).

To my surprise, after some pinching of the fuel-line, the main pump would become quiet for 15-20 seconds at a time. No more African killer-bee-like loud buzzing.

Does anyone know what such a phenomenon might imply, diagnosis-wise, for the overly loud main fuel-pump?

Thanks in advance ( and in retrospect...)