I am looking to find voltages for the varying pressures read from MAP. I keep getting the dreaded P0121 and I have checked my TPS sensor numerous times. My tuner is not local, so it is hard to get him to verify/change MaxMAP for conditions of the DTC.

I have had this setup since October 09' and never had any SES light issues until now. I am guessing the higher temperatures or load from AC are creating readings of a lower MAP or high MAP between 55kPa or 65kPa.

I do not have any kind of tuning software as of yet, I need to get other issues resolved first, but in the mean time, does someone have a voltage table for readings from the MAP?

TIA

 

bump...

 

to help we would have to know what map sensor is it and what psi you run

 

stock and N/A...?

 

i thought you wanted something different the first time i read it. any map settings should be stock if you havent changed your map. i thought you were running a aftermarket map.

for the p0131 test stock settings are error max map 65kpa error min map 55 kpa. also check you throttle cable to make sure its adjusted correctly. this code is for a test so you could disable it by setting the min to 0 and max to 100. maybe something was over looked in the tune dosnt seem like a huge problem.

 

Oh, sorry, I didn't mean to confuse things. Its not a problem at all, it is a nuisance and has been dormant until the temperatures have risen. The tune is from PatG. He is in Victoria, and I am in Houston. Not worth driving down there so he can read my MAP values.

I am just curious to read the voltage across the MAP sensor and see what absolute pressures I am achieving. This way I can know if I am above or below 7-8.5 PSIA or 55-65kPa. This is more or less out of curiosity more than anything else as the engine pulls strong.

I have tested the TPS and reads accurately, as far as I can tell. Only thing left is the readings of the MAP. I am assuming that they are out of range, as this is a pretty healthy cam. So, anyone have values for voltage and pressure ratings?

 

I have run across MAP sensor datasheets on Delphi's
web site.

As a rule they all appear calibrated to 0.5V at 0,
4.5V at rated max (105kPa for 1-bar) and a straight
line transfer characteristic.

 

Just to confirm, for stock MAP, the volts starts at 0.5V @ 0kPa absolute up to 4.5V @ 105kPa absolute with a linear relationship?

So, for the sake of simplicity, x-axis = Volts with a range of 0.5-4.5V and y-axis is kPa absolute with a range of 0-105kPa absolute.

so the formula is (Y)kPa = 26.25(X)V - 13.125

Correct?

 

Here are two current Delphi datasheets. I notice the low
end now is 0.25V (pretty sure 0.5 used to be the norm)
and the high end varies; 4.85, 4.5V variously. Might be
more vehicle-specific info in the shop manual.

The low end pegs before you get to zero, except for the
"low pressure" sensors that can read negative.

Given the fog factor you probably want a P/N specific cal
curve, but this is the best I've been able to turn up.

 

Thanks for the specs. From my rough calcs, the new formula is...

(Y)kPa = 18.91(X)V - 10.29

from the standard calibration. Which book would you think would have a more detailed information about this particular sensor? I found the P/N PS10002 and searched Delphi's website, but they don't have anything that specific on there.

Question, those negative readings you referenced above, must be gauge pressure, not absolute?