Question about MAP voltages
04-12-2009, 09:12 AM
#1
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Question about MAP voltages
I currently run the Dyno-Jet wideband system. It has provisions for inputting a 0-5v signal from sensors into the wb. I use one for TPS and would like to run a signal from the MAP sensor if I can.That way I can see the AFR at rpm/load. I searched and found that the MAP does give 0-5 voltage signal back to the PCM. My question is.... what is the voltage at no load supposed to be and what is the voltage supposed to be at WOT? I need those voltages to be able to calibrate the analog setting on the WB. It would also be nice to hav a chart that shows the Kpa/Hg crossreference if anyone has one
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04-12-2009, 09:22 AM
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OK did some more searching and found this...
So,at idle, I can set the low end of the sensor value to what the reading is at idle, then shut off the engine, leaving the key on and set the high end there and it should be the same value as if at WOT?
When you go WOT with the engine under load, the MAP reading should approach the 4.7V (barometric pressure) you get when you first turn the key to on, but don't start the engine. A faulty MAP reading will have a major impact on how the engine responds to throttle transitions, since the MAP reading is the basis for where the PCM sets the ignition timing, and which long term fuel correction cell it uses.
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So,at idle, I can set the low end of the sensor value to what the reading is at idle, then shut off the engine, leaving the key on and set the high end there and it should be the same value as if at WOT?
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