I've got a 94 E150 conversion with a 5.0 that left me on the side of the road yesterday. It just died while going down the road. The engine would crank, run for a few seconds and die.

After a frustrating day by the road I found that it would run with the MAF unplugged. Plug it in and it starts and dies.

Spark is good. New plugs and dist cap. New fuel filter. Fuel pressure is within spec. Fuel pressure regulator test OK.

Everything I've read states to test the MAF with the engine running. Obviously that can't be done. The only code I get is a 157 code which states MAF sensor under expected voltage.

Recently the van has developed a miss on idle and sometimes stumbles on take-off. That's the reason for the new plugs, filter ect.

Now, without the MAF plugged in the miss and stumble seems to be gone. What gives? If it's bad, shouldn't the engine run anyway? Is it the MAF that is causing the drivability problems? Can it be cleaned or must it be replaced?

Is this symptom disguising something more sinister waiting to rear its ugly head?


Or can I just leave it unplugged and say 'The hell with it"?

Any help would surely be appreciated.

 

Interesting. I'm surprised that it runs without the MAF sensor connected, since that's the only way that it knows how much air is going into the engine.

Take a look at the MAF sensor; see if there's something stuck in it. There could be something shorting out the very fine wires that sit in the airstream. Check out this article:
http://www.aircarecolorado.com/repair/acnews/oct01.htm
Or this one which is a Ford TSB:
http://ww2.v8sho.com/SHO/TSB982310Ma...tamination.htm

And, some testing:
http://www.champion-auto.com/PDF/50_AirFLSensor.pdf
http://barrycrowder.net/articles/meter.html

 

Thanks for the links bigric.

I'm going to get out there after work today and see what I can find out on this thing before simply throwing a new sensor at it.

The way it dies when the sensor is plugged in has me suspecting some kind of short.

 

The Haynes manual should tell how to test the MAF with a multimeter - is that one of the references you're reading?