grahamtwatson
NAXJA Forum User
- Location
- Woodinville
1990 Cherokee Ltd, 4.0L, Auto, 200k miles...
I'm trying to track down why I'm only getting 11mpg, and just looked at the output voltages from the MAP sensor. At hot idle I'm getting 1.9~2.0 Volts. It will go down to about 1.0V on overrun. The Jeep Renix MPI manual says this should be 0.5V~1.5V, but I've seen elsewhere on that 2.0V is good. Input voltage and output voltage with engine off are in spec.
I can see that if the voltage is high it would cause a rich idle, and possibly make the engine run rich at part open throttle as well, which in turn would cause high fuel consumption.
So, is my MAP in spec or not? If it's out of spec, would the high voltage at idle be a valid reason for bad mileage?
I'm trying to track down why I'm only getting 11mpg, and just looked at the output voltages from the MAP sensor. At hot idle I'm getting 1.9~2.0 Volts. It will go down to about 1.0V on overrun. The Jeep Renix MPI manual says this should be 0.5V~1.5V, but I've seen elsewhere on that 2.0V is good. Input voltage and output voltage with engine off are in spec.
I can see that if the voltage is high it would cause a rich idle, and possibly make the engine run rich at part open throttle as well, which in turn would cause high fuel consumption.
So, is my MAP in spec or not? If it's out of spec, would the high voltage at idle be a valid reason for bad mileage?