My 1994 with 65,000 gets an intermittent error code pointing to the mass air flow sensor. Since it's an expensive repair, the mechanic is trying to prove which part needs replacement. When he disconnects the cable assembly on the air flow chamber, he says the engine should stall. But it doesn't, it keeps running fine. Is there a way to prove a part is defective before it is replaced?
Many thanks for any comments.
Mike

 

Your car is an OBD1 I believe, but still a bad MAS is a bad MAS, is this mechanic a Mercedes mechanic?, I've disconnected by accident the MAS on my 99 C280 and the engine kept on running, so I don't think this is a bencmark test.

 

it's hard to diagnose by just disconnecting the air mass sensor. the engine will still keep on running, but on limited acceleration only. the rpm will first low down during the disconnection and will immediately go to idle speed... but you can feel the frequency of adaptation.

without the aid of scanner for actual value, it's hard to tell. your injection time should be about 3.2 milliseconds at idle speed with the airconditioning off.

if he say the engine should stall, then he was wrong. there is an emergency value that takes place on every sensors on the car.

if you hear a slight backfire on the intake area during acceleration, or the car drives sluggish than before... then the air mass sensor got problem.