I am currently monitoring my MAP sensor. Oddly I am getting a steady 5 volts regardless of engine load. Yes I checked the schematic and verified the terminal location and wire color. I am wondering as vaccum increases should it go up or down. How does the PCM deal with this unvaried value. I thought the main point of this was for controle of the ignition timming but if there is no fluctuation is the PCM just running timeing based on learned memory. I noticed after doing the circuit tests wich required disconnecting the battery and PCM connector. When I hooked it all back up the engine had a rough idle for about 1-2 minutes. Guess it was relearning. But the MAP sensor signal never moved just a steady 5 volts. I then checked the terminal for the 5 volt supply just to be sure the manual didn't have a misprint. Same value with no fluctuation. But running fine, other than my intermitent stalling problem which lead me to monitore the sensor. Waiting for the stall to happen to see if the sesore is not sending a signal at that moment of stall.

Thanks

 

voltage should change as vaccum changes.I believe it it should be like .5 volts at idle and increase as vacuum decreases.the computer will go into limp home mode and adjust timing based on the programming ma mopar gave it.it won't adjust for best power and mileage in limp mode.i have read of other vans with similiar stalling and changing the map sensor fixed it

 

yeah I plan to replace it in a few days. Waiting on some $$$. The service manual said 1.4 - 4.1 at normal operating temp and in nuetral so it is apparently bad regardless. I was just wondering what the values as pressure changes would be. Nissan always gives that info in the service manual but I seem to rarly find that info for many manufacturers. It just helps to diagnose problems when you have a full understanding.