MAP sensor 99kPascals?

[white98mo]

I need some help from you experienced V6 troubleshooters. I have installed a replacement engine. The engine will start and run for a few seconds. I have access to an oscilloscope so I verified the 18X and 3X signals are getting to the PCM. I hooked up a Scan Tool last night and ran the Diagnostics. The TPS change is indicated on the scan tool. IAT and Coolant temperature read reasonable . The MAP sensor is out of range. The scan tool shows 99kPA and I think the manual says the max is 75kPA.

I checked the MAP sensor signal for a short and MAP reference to short to 5V. The MAP wiring doesn't indicate a problem that would signal the MAP to this high Barometric Pressure. The service manual recommends replacing the PCM.

Would a MAP sensor reading out of bounds allow me to start the engine but shut the engine down when the PCM is trying to takeover control?

[97rs4life]

Re: MAP sensor 99kPascals?

Does the replacement engine have any mods to it or anything or is it bone stock?

Our 1bar MAPs max out at 104kPa, so if your reading is accurate it is not quite maxed out but still pretty high.

Do any SES codes come up when it runs for a few seconds? Is it your original PCM or the PCM from the replacement engine?

[white98mo]

Re: MAP sensor 99kPascals?

Replacement engine is stock. The PCM I'm using is from the original 3.8 that I had problems with that never were figured out. I recorded PO107 and P0452 after measuring the MAP sensor itself. MAP showed 10 kPAS with MAP disconnected and 99 with MAP connected.

I had a vacuum gauge attached when I first started firing up the engine...about 20 in Hg when engine fires an then of course it falls off when the engine dies