: Fans turn on



HUF
11-18-10, 02:57 PM
This is the second time the both cooling fans turn on at a short trip to the grocery store. The temperature does not even reach the operational. At the same time EGR related 32 code sets up. What's going on, gents?

sven914
11-18-10, 03:42 PM
Not positive, but the computer not seeing the EGR doing it job could be throwing the car into open loop mode. In open loop, the computer ignores all of it's sensors and operates the engine based on a preset program of parameters. To prevent the engine form overheating in the absence of the electric eye, the computer might command the fans on as a safety precaution.

csbuckn
11-18-10, 07:29 PM
That's good Sven, I was thinking temp sensor but yours makes more sense.

HUF
11-18-10, 07:57 PM
Thanks for the reply. Makes sense despite I thought the car is in open loop until it reaches certain temperature.

I spilled a few drops of DOT3 from the master cylinder reservoir a few days ago. Need to check if it reached some connectors down the road. Besides that and battery replacement, I cannot recall anything that could cause that condition.

sven914
11-18-10, 09:53 PM
^When you first start the engine, the computer does not used the engine sensors for fuel metering until the O2 sensor(s) heat up and begin switching. When you first start the engine, it is operating in open loop but as soon as the computer sees a signal from the O2 sensor, it goes into closed loop and uses the engine sensors to determine the correct fuel mixture. On OBD-1 cars, when the computer sees a problem and sets a DTC, the computer goes into default fuel metering which takes it back into open loop mode.

HUF
11-18-10, 10:55 PM
^When you first start the engine, the computer does not used the engine sensors for fuel metering until the O2 sensor(s) heat up and begin switching. When you first start the engine, it is operating in open loop but as soon as the computer sees a signal from the O2 sensor, it goes into closed loop and uses the engine sensors to determine the correct fuel mixture. On OBD-1 cars, when the computer sees a problem and sets a DTC, the computer goes into default fuel metering which takes it back into open loop mode.
And the default fuel metering can result in rich condition and hurt the cat converters, right? Does defaulting to open loop necessarily turn the both fan on?

sven914
11-18-10, 11:45 PM
^Hasn't killed my cat... And I don't know your system thoroughly enough to know that the fans should even come on; I just know some cars will do that when thrown into open loop.

HUF
11-19-10, 12:30 AM
Ok, thanks. Will clean the EGR solenoid connector tomorrow and see if it helps. The EGR valve is only 5,000 miles old, The passages are clean.