Hey guys and gals. I usually don't post, but I am along time lurker. I have been searching previous posts for sometime and have not found anything mentioned about what I found concerning a failing thermostat and the affect it has on gas mileage. So if I am posting a repeat or in the wrong forum, let me know.
I have found many posts that refer to the bad gas mileage being a precursor to replacing a bad thermostat. I also found many questions about gas mileage and the posters were refered to checking for bad sensors.
What made me start digging deeper into the mystery of bad gas mileage was that it was coming and going. Bad thermostat? Coming and going? I always held 3 bars no matter the ambient temperature. Sometimes gas mileage in the 50's traveling 70 mph down to 35mpg traveling under 50mph What in the world?
My problem was not necesarily the thermostat, it was the ECT sensor. The ECT sensor does more than send a signal to the dash and ECM. It also controls the power to the MAP sensor, the TP sensor, IAT sensor, and O2 sensors on both banks. In essence, the signal comes from the ECM to the ECT sensor and the the ECT sensor turns on the other sensors that I mentioned. If the engine coolant fluid is not hot enough the ECT will not turn on the other sensors, essentially never letting the ECM get in to closed loop.
To test this, I jumpered the signal wire to the ECT (yellow/blue) to the power wire going to the other sensors (green/orange). Sure enough, that was the answer! My bike now runs in closed loop with my gas mileage back to normal. Before the jumper, all my sensors read as dead or not working. Now, all the sensors are reading correctly.
AT least on my bike, I found out what was going on.
Like I said, if this is old news, sorry for the repeat. I was not able to find it anywhere else in the searches.
Pop
I have found many posts that refer to the bad gas mileage being a precursor to replacing a bad thermostat. I also found many questions about gas mileage and the posters were refered to checking for bad sensors.
What made me start digging deeper into the mystery of bad gas mileage was that it was coming and going. Bad thermostat? Coming and going? I always held 3 bars no matter the ambient temperature. Sometimes gas mileage in the 50's traveling 70 mph down to 35mpg traveling under 50mph What in the world?
My problem was not necesarily the thermostat, it was the ECT sensor. The ECT sensor does more than send a signal to the dash and ECM. It also controls the power to the MAP sensor, the TP sensor, IAT sensor, and O2 sensors on both banks. In essence, the signal comes from the ECM to the ECT sensor and the the ECT sensor turns on the other sensors that I mentioned. If the engine coolant fluid is not hot enough the ECT will not turn on the other sensors, essentially never letting the ECM get in to closed loop.
To test this, I jumpered the signal wire to the ECT (yellow/blue) to the power wire going to the other sensors (green/orange). Sure enough, that was the answer! My bike now runs in closed loop with my gas mileage back to normal. Before the jumper, all my sensors read as dead or not working. Now, all the sensors are reading correctly.
AT least on my bike, I found out what was going on.
Like I said, if this is old news, sorry for the repeat. I was not able to find it anywhere else in the searches.
Pop