"P1400 manifold differential pressure sensor circuit malfunction"

[kr.k]

seems like my MDP sensor is dead. can anybody tell what is it`s purpose and should I change it asap or should I replace it at all? It is rather expensive piece and if it sits there ONLY to control the duty of turbocahrgers waste gate acuator solenoid (soon to be disconnected) I see no reason to change it at all. So please let me know if it has other important tasks!
thanks

 

[dave99gst]

ive heard the ecu uses the MAP for alot of differant things and its recomended to keep it.

 

[kr.k]

Originally posted by dave99gst
ive heard the ecu uses the MAP for alot of differant things and its recomended to keep it.

do people that have aftermarket intake manifolds use those sensors?

 

[talonted_one]

I junked that sensor years ago with no KNOWN side effects. I'm not saying there were none, just none that I was aware of.

 

[zdrux]

The MDP is the only way the ECU can know how much pressure is in the intake manifold at any given time. If you ask me, this is VERY important for proper air/fuel calibration and calculations by the ECU.

And I would love and listen and see just how hard people try and explain to me that the MAF is what gives you the signal as many believe.

Now before anybody tries flaming me, just listen to what my opinion on this is. Firstly, the MAF sits BEFORE the manifold therefore there is ABSOLUTELY NO WAY physically/scientificly that it can sense/measure "air pressure" in the manifold.

Secondly, your in-dash boost guage gets it's signal from the "Volume Air Flow Sensor" which is your MAF/MAS and believe it or not does not actaully show the PSI that is in your manifold but an estimation based on what the MAF/MAS gathered from the air intake temp. baro pressure, and air-flow.

The MDP is a big companion to the MAF/MAS used to fine-tune these air-readings for proper fueling and engine management. Otherwise ofcourse it would not be included with the car AND would not showup as a CEL when removed.

I`m welcome to other opinions and comments on this.

 

[BISHILVR]

here's the fact's: the map sensor(manifold absollute pressure) sensor on the 2g is there for the purpose of checking the function of the egr valve ONLY, it does this by checking for a drop in vacuum levels within the manifold when it commands the egr solenoid to open the egr valve....if it does not see a drop in manifold pressure during this time it flags a check engine light......this is the reason the 1g does not have the map sensor...the 1g when it was in production did not have to meet the same strict emissions laws that came along with the obd2 systems introduced on the 95 and later vehicles.....it does not use the map for fuel control at all so all you have to do is remove it or leave it on and replace it .... you will end up with a constant cel if you choose not to replace it with a good one unless you have your ecu reprogrammed to not check the egr operation(there is also other ways) just lettin ya know!