Mechanics

MY ENGINE TEMPERATURE SENSOR IS OFF (THE ETS OFF LIGHT IS ON) AND MY FAN DOESNT COME ON EVER.

1997 Pontiac Sunfire • 130,000 miles

My car is overheating and stalling out after 10- 20 minutes of driving/idling. The heater works and blows very hot so water pump must work fine. Could the bad sensor be causing the fan to stay off? I know I need to change the sensor and I ordered one, but should I get a new fan too? How do I test the old one?
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To test the fan, you can disconnect the connector and apply battery voltage to one wire and ground the other to test.

You can also remove the fan relay and bridge the terminals for the fan and power with a fused wire.

A bad sensor definitely can cause the not to run.


KHLow2008
Mar 18, 2012.
Update, found out the ''ets off light'' has nothing to do with engine temperature. It is the traction control, and I can turn it on and off with a button. However the fan still does not work ever. And the temperature guage never reads above half. It slowly rises to half while driving and appears normal, however the car behaves like it it is overheating, stalling after 10-20 minutes of non-highway driving. I ordered a temerature sensor, and now I am going to test the fan. When it stalls though, it is clearly way too hot. Just opening the hood you feel extreme heat, so I am thinking the sensor is bad anyway? It only stalls on warm days, and then only during city driving and after 10-20 minutes. Also the fan does not come on. My gut tells me its overheating but my temp sensor says its not. Could something else be causing this?


All your conclusions and "gut" are just flat out wrong. If you don't believe the temp gauge then use a laser thermometer or access the computer data with a scan tool. These engines are factory programmed to run up in the 225 degree range and you certainly can't tell the temp of the engine by opening the hood and feeling the air. That's just ridiculous.


Wrenchtech
Mar 18, 2012.
Ok, then I am going to assume that my temerature guage is correct and the engine does not overheat. But the engine does stall after 10-20 minutes of driving. What should I troubleshoot for this? I am taking it to be scanned today and hopefully that will give results. Also the engine only stalls on warm days, I am shure of this because I idle to test it and it will not stall if it is cold out.


You would need to check the idling system which seems to be the cause of the problem. Too low idling speed would result in stalling, especially when at operating temperature.

If it is the idling speed, get the trrottle body and IAC cleaned and retest.


KHLow2008
Mar 18, 2012.
You may have a bad IAC ( idle air control) but try eliminating any vacuum leaks and cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.


Wrenchtech
Mar 18, 2012.
Update, I found a cracked air hose that was whistling and repaired it, after the repair I was able to idle successfully for 90 minutes. The engine reached normal temperature after 30 minutes, so the idle issue appears solved. I will clean the throttle plate once the car cools down and then attempt to drive it in town to test it out. Thanks guys I almost bought a fan for it. Still not sure why the fan wont come on, but assuming that the engine is not getting hot enough to need it at idle.


Vacuum leakages would also cause erratic idling and stalling. Anyway cleaning the throttle body would only help so no harm doing it as it is not too difficult and won't cost much. The work would be worth the while.

The cooling fan only come on when necessary and would take at least 20 minutes or more for it to first come on when starting from cold, depending on weather.


KHLow2008
Mar 18, 2012.