I thoguht I'd get answers quick here as they are needed asap. There are 3 wires goign to the MAF sensor on the 86 2.8V6. Orange, brown, and black. Black is ground and that is good, orange gets 5volts form the computer when the car is running and orange gets 12 volts only when the car is in start. is this correct because if so then I need a new MAF sensor otherwise what is wrong? Thanks in advance - Adam Housley

PS-My MGB V6 runs and it is getting the error code for the MAF sensor and this is the only thing wrong. I can't time the engien because when I try to advance the timeing to where it is needed to be(it's retared right now) it will back fire. Hopefully I'll have a video with it running soon.

 

Adam,

I believe that the MAF should get +12V from the IGN circuit whenever the ignition is ON, not only in the START position. The 5VDC from the ECM is actually a reference that is switched to ground in a variable frequency square wave, with the frequency dependent upon the volume of measuresd air mass through the sensor. If you monitor the 5VDC output with an oscilloscope on a fixed horizontal time base, you can observe the change. A dwell or duty cycle meter will also show the change, but it is not necessarily relevant to actual flow rates.

The wire colors you listed are close:

 

Basically, you need to get +12VDC to the MAF "A" terminal. Check the fuse at the 12V junction block, the MAF relay, GAGE fuse, wiring at the relay, and the ignition switch if necessary.

It might be easier to temporarily jump a +12V source to the MAF sensor to see if the light goes away and operation returns to normal - Or whatever might be normal for a Chevy MGB...

 

Thanks I'll check that tomrrow