drakec9

@irodd Seriously! Im not convinced the map sensor has failed, i have an ms2 that is just over a year old. Didnt read a lick over 89kpa until 5 months ago. I will check for issues with the vacuum line. Is there a solid way to test the map sensor? Ive read of users that disconnect the vacuum line for the internal map and blow air into it whilst watching TS

irodd

iTrader: (4)

As already mentioned above by the person without a sense of humor, barometric pressure should be around 100kpa (check a nearest weather station for current pressure in Charlotte, NC) , so disconnect the vacuum line from the map sensor and check the reading in TS, should be around 100kpa.
if 100kpa - sensor is OK, check the vacuum line. if not 100kpa - sensor is failed or soldering between sensor and pcb.

Erat

iTrader: (5)

I just did it to mine. Blew to 110kpa.

And because this is a Miata forum, and this is probably more relevant. I sucked it down to 85kpa.


Edit* who says I don't have a sense of humor? Especially after that post^.

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irodd

iTrader: (4)

I was wrong Thumbs up

drakec9

Lolol well i guess my hunch was wrong, no matter what the MAP reading stays at 68kpa with or without a vacuum line attached, i am taking the ms2 out of the car now to see what may have happened. What could have cause this failure. it seems premature
here is a log you can see the map reading does not change from 68kpa and i un plugged the vacuum line a few seconds into the log

DNMakinson

iTrader: (3)

You could have the wrong MAP calibration. But if it used to be right, then that would likely not be the problem.

If the engine is not running, then the MAP reading should be about 100, whether the hose is connected or not. All the pressures equalize.

Also, one must be careful using weather stations' reports of barometric pressure. Unless you dig deeply, the normally reported barometric pressure (in inches of mercury) are altitude adjusted to sea level. Because weather stations care more about changes in barometric pressure than absolute, and because they want 27" (or whatever) to seem like a low BP no matter where you hear that in the weather report.

EDIT: Oh, Looky Here!

DNM

drakec9

Wow very cheap for a new internal thank you for the link. I will likely buy 2 gm 3bar sensors and mount externally. Only to simplify issues if i have this issue again during a track day i can easily replace it without pulling the ecu and soldering on the board. I am thoroughly surprised that the internal sensor did not outlast my 260k mile stock engine. But thats probably another post
I will post back hopefully reporting success once the new sensor arrives and i get it all wired and plumbed up. Thank you all for your help and input

drakec9

Update: New GM 3 Bar map sensor fixed all issues with a slight re tune of the fuel table, not sure how or why the internal map sensor in my MS2 failed