coolant temp sensor, sender questions

[cf3232]

This is correct. The voltage going to the sensor is not powering anything so it just decreases voltage because the resistance increases as the temp increases. 5 Volts is sent to it and something (the computer) connected to the wire reads the voltage on the line. The computer reads the voltage decrease and adjusts the variables that depend on the change accordingly.

 

[Bob Ayers]

bob, nothing personal, but the way i learned it (and apparently this is how it works) is as resistance increases in the sensor voltage drops (we are only working with 5v nots 12 or more) and the computer sees this and reads the specified voltage as a certain temperature. it then trims the map etc accordingly. not starting an argument here thats what classes and real world field work/testing shows. this is true with all sorts of variable resistance sensors including angle sensors (tps for example) heat elements (coolant temp sensors/mafs/o2 sensors/and eot sensors if equipped).

Again, totally WRONG!! As the resistance of the sensor decreases, the current increases, which make the voltage across the sensor decrease......just another example, where you don't know how OHMS LAW works!!!

 

[Bob Ayers]

This is correct. The voltage going to the sensor is not powering anything so it just decreases voltage because the resistance increases as the temp increases. 5 Volts is sent to it and something (the computer) connected to the wire reads the voltage on the line. The computer reads the voltage decrease and adjusts the variables that depend on the change accordingly.

You have that backwards, as the resistance increases, the voltage will increase, when the resistance decreases, the voltage decreases. If the sensor is OPEN, the voltage will
be 5V, if it is SHORTED it will be 0V.

 

[Bob Ayers]

this is true with all sorts of variable resistance sensors including angle sensors (tps for example) heat elements (coolant temp sensors/mafs/o2 sensors/and eot sensors if equipped).

O2 sensors are NOT variable resistance sensors, they are variable voltage sources....

 

[Bryan22]

bob, i wish you would take some of your knowledge and try to help someone once in a while instead of just arguing all the time. we know you're smart, that's great. how about pointing model a in the right direction with his problem instead of just arguing about it with everyone else! sheesh.

 

[Bob Ayers]

bob, i wish you would take some of your knowledge and try to help someone once in a while instead of just arguing all the time. we know you're smart, that's great. how about pointing model a in the right direction with his problem instead of just arguing about it with everyone else! sheesh.

When I see bad information posted, I'm going to correct it!!

Try to live with it!!!

 

[modelageek]

bob, we know you're smart,

I have not seen enough empirical evidence to convince me that the above statement is accurate