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Jake Cheek
Jake Cheek,
Category: Pontiac
Satisfied Customers: 26
Experience:  Automotive Technician at Hendrick Chevrolet
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My neighbor got a 2000 Pontiac Bonneville super charge 3.8.

Customer Question

My neighbor got a 2000 Pontiac Bonneville super charge 3.8. motor went bad so he put a regular 3.8 non super charge . He change wire harnesses and ECM want crank unless we unplug map sensor car cranks up than I plug it back up car runs fine. Do u have any ideas. Oh
Submitted: 10 months ago.
Category: Pontiac
Expert:  Jake Cheek replied 10 months ago.

Hi my name is***** to JustAnswer.

Sounds like a bad map sensor. When it is unplugged the ECU runs the default algorithm instead of using the map sensor reading. Even if you plug it back in during that drive cycle the ECU will not use it until the vehicle is restarted. I would double check the wiring harness for any damage to the MAP circuits. If that checks out I would replace the map sensor. I will provide you with a diagram of the MAP sensor circuit.

Customer: replied 10 months ago.
Ok took multimeter grey wire has 5 volts . And has good ground. Replaced map sensor same problem. Tried the map sensor on another car it crank that car up. I put my old computer on it it read check wire harness to pcm .
Expert:  Jake Cheek replied 10 months ago.

Did you check the signal wire to the map sensor from end to end? It should have 0 ohms from the PCM to the MAP sensor. It is the light green wire. On the PCM side it is the Clear connector. I will provide the pin location in the picture.

Customer: replied 10 months ago.
I ohm it out my number's on my multimeter did not even move
Expert:  Jake Cheek replied 10 months ago.

As in OL or 0 ohms?

Customer: replied 10 months ago.
It just says 00.0
Customer: replied 10 months ago.
I took a good a alligator clip and test both ohm it out I got 0.5 just to test my multimeter
Customer: replied 10 months ago.
My bad I had wrong pin it ohm out 0.7
Expert:  Jake Cheek replied 10 months ago.

I would run a new wire from the MAP sensor to the PCM and see how it runs. Sounds like a short in the signal wire

Customer: replied 10 months ago.
I raned wire still the same problem
Expert:  Jake Cheek replied 10 months ago.

As a last effort before I say it needs a PCM. Did you check the 5v reference on the grey wire while it was running? I would try that first.

Customer: replied 10 months ago.
Jake it has 5v I am really confused I sprayed some starter fluid in throttle body it cranks up and run . But it runs bad like the map sensor is bad
Expert:  Jake Cheek replied 10 months ago.

Leave the map sensor plugged in and unplug the MAF sensor. See if it starts

Customer: replied 10 months ago.
No it doesn't crank
Expert:  Jake Cheek replied 10 months ago.

Okay, maybe we just have a large vacuum leak. Have you started it and sprayed carb cleaner around the intake or other vacuum sources?