Hello, I have problems with my volvo v50 2007, 2.0 diesel engine
I believe car is running super rich. On start up, comes a cloud of blue smoke, engine rattles for 15 - 20 seconds, when warmed, there is hesitation on load between 1500rpm to 2100rpm. Its smells unburned fuel when car is idling, and you can see little smoke comming from exhaust.
If MAF sensor is diconnected, car runs better, almost no hesitation between 1500-2100rpms, but startup problems still exist.
I checked maf sensor and connector. I think maf is okey, but the connector has 4 wires it is Siemens VDO unit 5WK97002. Four wires comes to connector, when ignition is on I get parameters, (connector is not pluged into maf). |12V+| |0V| |+5V| |+5V|, as I understand it should be |+12V| |ground0V| |0V| |+5V|. Could you confirm that maf return signal should be 0V when ignition is ON.