Fan thread #XXVI 89A4
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
I'm sorry to take so long to reply. I got called away. First, please understand that I am not nit picking or trying to start a fight. Some of what you say doesn't make sense to me and I would appreciate your help in making me understand exactly what you are saying, or how you are testing.
My FSM shows the resistance in Ohms, of the thermistor at different temperatures, not the voltage based on a 5 volt input.
That is one place where you lose me. Disconnected, I am reading the voltage from the ECM pin to ground. I see 5 volts. I'm with you so far. THEN I hook up the harness to the thermistor, and check the voltage, again. Is this still from the ECM pin to ground? The path of least resistance dictates that I will STILL see 5 volts. The way *I* see it, I am still measuring the voltage available at the ECM.
I agree and understand.
That is where you lose me. It seems to me that the lower the resistance the the lower the DROP and the higher the VOLTAGE.
That takes care of most of my confusion. If you will be so kind to explain, I may have a few more questions. Thanks. I am sorry to hear of cuisinartvette's expanded problems.
RACE ON!!!
Originally Posted by SunCr
FSM's have charts for the range of the Thermistors used by GM.
Originally Posted by SunCr
Starting at the ECM Pin and with the sensor disconnected you will (should) see this voltage. Hook it up and check again (at the pin). Depending on the resistance in the sensor, that voltage will drop.
Originally Posted by SunCr
Higher the temp - lower the resistance
Originally Posted by SunCr
lower the resistance-higher the drop.
That takes care of most of my confusion. If you will be so kind to explain, I may have a few more questions. Thanks. I am sorry to hear of cuisinartvette's expanded problems.
RACE ON!!!
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
It's all electrons to me - but think or it as water moving through a restriction. The pressure will be less on the downside then on the upside. Decrease the restriction and the pressure on the downside increases. Move voltage through a resistor and you get the same results. A guy named Kirchoff discovered this and postulated that the sum of the drops is equal to the source. I'm not an electrician, nor have I ever thought to add the two voltage readings to see if they come up with the source (though theoretically they should). I just look at what the meter tells me and try to figure out if there's a problem.
