MAP sensor ground question
03-01-2019, 05:11 PM
#1
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Year: 1992
Model: Cherokee (XJ)
Engine: 4.0
MAP sensor ground question
I was testing my map sensor with a hand vacuum pump and the voltage was a bit off. About .02-.03 volts off which I’ve read is a big difference. I checked the ground and from the MAP sensor to the chassis/battery there is a resistance of 25 ohms. I believe that is too much (should be under 5). Does this sound like too much? I’m thinking about tapping into the ground on the sensor and running it to a local ground
03-01-2019, 06:24 PM
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Year: 1989
Model: Comanche (MJ)
Engine: 4.0
On a 92, the sensor ground is not the same as the chassis ground. The sensor grounds only go back to the PCM. How accurate is the gauge on your hand pump - probably less accurate than the MAP.
03-01-2019, 06:27 PM
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Year: 1992
Model: Cherokee (XJ)
Engine: 4.0
Gotcha. So is there supposed to be continuity between the sensor and the chassis at all? I’m not confident that the hand pump is super accurate.
03-02-2019, 11:34 AM
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Year: 1989
Model: Comanche (MJ)
Engine: 4.0
The earlier Renix Jeeps had all the sensors connected to chassis ground. I think all the later Chrysler based electrnocs keep the sensor grounds seperate to minimize electrical noise.
03-02-2019, 12:07 PM
#7
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Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
There is a "gang" of grounds on or near the dipstick that ground everything! (TCU, Puter, sensors....A must that those are cleaned and tight.
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