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GM 3bar KPA issue

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Hey guys, I hope this is the right area for this topic. So I am doing starting a tune on my RB20det highly modified running an AEM Infinity with a GM 3bar Map sensor. I have had a base tune in this and it was running decent but it has sat all winter and just starting the process back up to finish the tuning.

I have run into an issue now where with the car off I am getting a raw voltage reading of 1.28 volts on the map sensor and a scaled kpa reading of 81.31. When I attempt to start it the kpa at idle lowers to around 71 kpa at 1000 rpm and will decrease as the rpms increase. If I unplug the sensor the voltage is at 5 volts. I am thinking maybe a wiring issue but not certain and wanted to see if you guys have any direction on where I should start troubleshooting. Thanks for you help.


Attached Files

What altitude?

I like to use a test gauge setup hooked to the sensor and a pressure regulator, then read the volts out as you increase pressure. you can tune the curve to suit and check for repeatability. Only need the key on for that test. also use a hand vacuum pump to pull below ambient pressure. That should get you pretty close.

We are at 5280 ft. So pretty high and from doing some research it looks like it maybe reasonable readings I am getting it just didn’t think it was.

Johnny thanks for the tips!

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