Volvo Repair: How to test mass air sensor?, mass air sensor, volvo 850 wagon

Question
QUESTION: My wife has a 1997 Volvo 850 wagon, non-turbo.  The car is idling terribly (when it starts) and running rich (black smoke, gas smell).  When I disconnect the MAF sensor, the car runs smooth.

I want to test the MAF sensor before replacing it in case there is a problem with the wiring.  How do I test it?  I'm looking for the electrical specs for testing the plug coming to it from the engine (voltage, ohms, pin numbers) and the specs for the MAF sensor (ohms, numbers).  Can you help?

Thanks,
PeterM

ANSWER: Peter, you dont need to worry about any of that.  Unplug while its running then plug it back in.  If car dies, meter is bad.  Roger

---------- FOLLOW-UP ----------

QUESTION: Roger,

I had already done that, and the car did die when the MAF was plugged back in.  The reason I wanted to test the MAF was to avoid spending $175 on a sensor if the problem wasn't the sensor for some reason.

So, I spent the $175, plugged the new sensor in and... the car still runs like garbage, with all the same problems of the rich mix, etc.  I'm now out $175 on an unneeded sensor.  

Any ideas what else to check?  I drove the the car with the MAF sensor unplugged for 12 miles as a test, and it works perfectly as long as the MAF is unplugged.  I also replaced the fuel filter initially when the car was stalling since I thought that was the original problem.

Thanks,
PeterM

Answer
Peter, $175 for an air mass meter?  Where did you get that? I hope its a Bosch meter.  Well, the ECT sensor provides the signal for injection spray and those go bad at times.  Did you have someone scan the car or do you have a scanner?  It can be so many things.  02 sensors are a possibility.  Its obviously overfueling.  Check to see the coloration of the sensor on the thermostat housing.  If its green and corroded, that may be on of the culprits.  Roger