if that sensor was bad could it prevent the car from starting. i am highly doubting it, but just checking.

Nope.

didnt think so. thanks.

water temp sensors do 2 things:
1. Make the temp guage in the dash move.
2. Turn the radiator fans on.

doesnt it tell the ecu when to go out of "cold start" mode? if so, wouldnt it then affect gas milage?

Originally posted by eclipzGST
water temp sensors do 2 things: 1. Make the temp guage in the dash move. 2. Turn the radiator fans on.

EDIT: Not sure if your talking about a 1g or a 2g, if its a 2g, disregard my statement, i'm not familar with the 2g electrical system.


Actually, 1g's have 4 coolant temp sensors, depending on which one your asking about, it can do 1 of a few things.

First , the one at the bottom of the radiator, that activates the main cooling fan.

Second. The white tipped plug at the top of the thermostat neck, that is the secondary temp sensor for the a/c fan, if the car gets hot enough without the a/c on, it will trigger the a/c fan to come on as well as the main fan.

Third. The single male end at the bottom of the t-stat housing, that is the signal for the gauge

Fourth, the double male ended one next to the single end, this is the signal for the ECU, it is also VERY important, It controls a hole slew of things including cold start up enrichment ( can cause car to crank up and die repetadly ( it happend to me for a while ) , it also controls injector pulse width, timing maps, fuel trims, and timing advance/retard.

the fourth one is VERY important to performance,gas milage, and start-up.

If the CTS has an open, it will fail to default which is set around -40F. This will dump massive fuel and definitely cause starting problems. This will cause you to operate in closed loop 100% of the time. If it has a short to ground it will pull fuel like crazy, also hindering startup. This can cause alot of things like knock, timing reduction and the cooling fans staying on constantly.

Default is -14* btw

well, i installed a new two wire sensor and it looks to have gotten rid of the CEL. the owner says it hasnt come on since we changed it. still doesnt start sometimes. its got new wires, plugs, and battery. im thinking it might need a coil pack, which i am not interested in changing. meh.