devildog0
NAXJA Forum User
- Location
- Hunt County Texas
I have been trying to improve my poor fuel mileage (12-14 mpg) on my stock 95 Country. I've replaced the cracked header with a non cracked one, replaced the original looking fuel filter with a new one, full tune up with plugs, wires, rotor, cap and air filter, new O2 sensor, throttle body and IAC fully cleaned (carb dipped)
Visually inspected all vacuum lines and Checked for vacuum leaks with an unlit propane torch on low and found none. I'm currently building a smoke tester but the vehicle exhibts no other vacuum leak symptoms other than poor fuel mileage.
Today I tested the coolant temp sensor (in the thermostat housing) and the intake air temp sensor and bounced my readings off of the chart below. Temp readings were taken with an IR heat gun on the thermostat housing and the sensor bodies themselves (so may be off a little one way or another but should be pretty close) and OHM readings were pulled with a digital FLUKE multimeter.
Thermostat housing sensor
212 degrees shows 960 ohms. Based on the chart this is feeding the ECU with lower than actual engine coolant temps.
Intake air temp sensor measured 150 degrees and read 2,300 ohms which again going off the chart shows to be feeding incorrect data to the ECU showing lower than actual intake temps.
I'm going to call the parts department tomorrow since I'd prefer to have Mopar sensors (they are pretty good on parts pricing) and see if 1)they can still get the sensors and 2)how much they cost but before I drop the money on these can anyone pick apart my troubleshooting other than not testing them in a pot of hot water vs using an IR gun while mounted to the Jeep?
As far as I can find the above values apply to both the coolant temp sensor and the intake air temp sensor
Cross posted on Cherokeeforum and JeepForum
Visually inspected all vacuum lines and Checked for vacuum leaks with an unlit propane torch on low and found none. I'm currently building a smoke tester but the vehicle exhibts no other vacuum leak symptoms other than poor fuel mileage.
Today I tested the coolant temp sensor (in the thermostat housing) and the intake air temp sensor and bounced my readings off of the chart below. Temp readings were taken with an IR heat gun on the thermostat housing and the sensor bodies themselves (so may be off a little one way or another but should be pretty close) and OHM readings were pulled with a digital FLUKE multimeter.
Thermostat housing sensor
212 degrees shows 960 ohms. Based on the chart this is feeding the ECU with lower than actual engine coolant temps.
Intake air temp sensor measured 150 degrees and read 2,300 ohms which again going off the chart shows to be feeding incorrect data to the ECU showing lower than actual intake temps.
I'm going to call the parts department tomorrow since I'd prefer to have Mopar sensors (they are pretty good on parts pricing) and see if 1)they can still get the sensors and 2)how much they cost but before I drop the money on these can anyone pick apart my troubleshooting other than not testing them in a pot of hot water vs using an IR gun while mounted to the Jeep?
212 farenheit 185 ohms
160 farenheit 450 ohms
100 farenheit 1600 ohms
70 farenheit 3400 ohms
40 farenheit 7500 ohms
20 farenheit 13,500 ohms
0 farenheit 25,000 ohms
-40 farenheit 100,700 ohms
As far as I can find the above values apply to both the coolant temp sensor and the intake air temp sensor
Cross posted on Cherokeeforum and JeepForum