Engine Fan Timing/Temp

[Fenners]

Hey guys, i have a vs v6 with El Falcon thermos, i have them wired up to run off the factory wiring and what not, i know the engine fan is run by the ecu, ie the fan will get turned on by the ecu when it reaches a perset temp and i was wondering if this can be changed? i would like it to come on earlier? also according to the temp guage on the dash roughly when should the fan kick in? i may need a new ecu temp sensor. Cheers Guys.

 

[deanos70]

You can get those adjustable thermo fan switches

they mount near the radiator and a copper probe goes under the radiator hose into the radiator
then the switch has a dial on it so you can adjust when you want the thermos to kick in
think they are about $70 from an auto store , then just tape up the wires from the ecu to the fan
something like this Controller & Switches

or the other way is to tap a thermo switch into your water somewhere, its like a temp sender
and it will cut in an out according to the temp rating of the switch

 

[RX25SE]

Be mindful of the fact the BCM and PCM switch the thermos. Because they switch low and high at two different temps they have a fail safe. Also if sensor signal is lost, the fans default to high speed regardless of temp.
If you are using the factory setup to switch the Ford fans you should be fine.
If you think the engine temp is too high it maybe the usual dodgy gague, signaled from a different sensor. Real engine temp from the sensor can be checked through most scan tools if you have acess to one.
If an EFI engine runs below its designed temp the PCM can overfuel the engine or retard timing as it thinks it too cold. This may affect economy and driveability.


Personally I have never liked the aftermarket sensors that sit in the upper radiator hose. They tend to leak and cycle over a large range. I believe you can get adjustable controllers that read off the gauge sensors single wire.

 

[deanos70]

If you unplug the wires at the thermo fan that shouldnt affect anything ? or will it ?

the ecu is still reading temps when they arent enough to trip the thermo fan

the ecu will still read off the temp sender and open the circuit for the thermos then putting current into the wires to the thermo fan plug

or does it need the thermo plug connected to finish the circuit

 

[RX25SE]

The ecu reads temp from a two wire sensor near the thermostat.
This information is used to calculate fuel load / timing advance / cold idle speed / fans on etc. This is called an input circuit.
The ECU switches relays on and off to drive devices such as fuel pumps, injectors, fans etc. This is called an output circuit.
If the fans are unplugged the ECU still reads temps.

 

[The1]

The fan cut in and out trigger points can be changed in the memcal tune.

109Deg cut in 105Deg cut out for high speed fan 104Deg for cut in and 100Deg cut out low speed fan is the typical stock values in most vs memcals which is ruffly 3/4 and 1/2 on most gauges.

 

[mike49]

my thermos are wired up separetly from the ecu and wiring harness..

wired them up so i can turn them on and off manually by a switch on the dash

i preffer it that way
but that might be just me


sorry for going off topic

 

[moff_man]

most vr/vs temp gauges read 3/4 before the fan kicks in. i have seen some kick in at 1/2. the temp scale on these dashes is not that great where the first notch is about 70 deg c and 1/2 around 100 and there on and so forth