Possible MAP sensor problem?

[DanJ]

So here i am sitting in bed reviewing my scan from my recent trip to Gameworks in Schaumburg on Saturday. I'm looking at my MAP and it says i hit 22psi at 74% throttle?! wtf is this? I did take the map sensor off when i did some work on the car last fall but I'm not sure it would be possible to reconnect the vacuum lines the wrong way. There is no way I'm running 22 pounds of boost on an M90 with a 3.4 pulley. Also, i don't recall the boost gauge showing numbers like that. Any ideas?

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[1998gpgt]

What was the kPa value?

 

[DanJ]

I believe it peaked at 158. I went in options and changed it to psi and that's what shocked the hell out of me as I'm not used to using kpa.

 

[1998gpgt]

Yep that's your problem right there. The psi reading is adding the first bar (100 kPa) of manifold pressure to the 58 kPa of boost. Each bar(100 kPa) is equal to 14.7 psi. So you are seeing the reading of 14.7 psi + ((58/100)*14.7). This would result in seeing a value of 23.226 psi. This value is actually correct if you are simply looking to measure the manifold pressure. Because the manifold pressure while in boost will be equal to the barometric pressure plus the boost pressure. So...

Set that scan parameter to boost rather than psi and you will be seeing the correct value.

 

[DanJ]

Thanks, makes sense.

 

[1998gpgt]

Okay cool. I wasn't sure If I was a little too wordy with that or not.