Cooling Fan Logic Wierdness

[Kryzaach]

Hi Guys,

I have a weird situation with my FN2 that I wanted to run past people who may be in the know.

I've noticed since firmware v2.2.7, possibly one or two version previous to that, that the cooling fan has been running strangely.

The fans will not turn on until the coolant temperature really starts to climb, up in the 220-240 Fahrenheit plus range.

When they do turn on, both fans come on at low speed.(or at least it seems to be low speed to me, but I have no basis of comparison)

This brings the temp back down eventually. Once this happens, the fans cut in and out according to the "Radiator fan on" and "Radiator fan off" calibration settings as far as I can tell.

I'm concerned that if they really are running at low speed that the car will have trouble maintaining temperature during the summer(it's still winter right now in Perth).

I've checked through the circuit diagram and I believe the only scenario this can occur is if only the "FAN LOW CTRL" signal is being sent instead of both the "FAN HIGH CTRL" and "FAN LOW CTRL" signals.

As far as I am aware, the "FAN LOW CTRL" signal should be constant or pretty close to it, outside startup.

I don't have an HDS, so I can't test the signal output to confirm 100%

I'm concerned that the fan logic has become screwed up in the last few versions of the firmware.

If not then my ECU may be on the fritz.

I'm going to ground the radiator fan relay temporarily to simulate the constant "FAN LOW CTRL" signal.

This will immediately tell me which signal is being sent.

If anyone has any other ideas, please throw them my way!

[Kryzaach]

I've also noticed that the old ECT and ECT2 sensor readings have been combined into a single ECT reading.

The ECT2 reading in my old datalogs is now all over the place.

Is this normal, and is there a way to undo it?

Both sensors seemed to be reading correctly in the previous firmware.

Could it just be a dud sensor or is ECT2 not supported in 2.2.7?

(I've just opened some really old logs where I am certain that ECT2 was reading correctly and it is still all over the place)

[Spunkster]

You have not posted your calibration or a datalog showing the problem.

[Colvert]

I came across this on another forum. Maybe it will add some insight.

Just a heads up for folk running the up to date beta versions of hondata.
I had a cooked crankshaft sensor as the engine was running hot at idle. I tried everything I could think of. The cooling fans didn't kick in not matter whatZ thermostat and sensing units were all tested and worked fine. Coolant system was bled and new coolant flushed through. Still I got a rough idle and ECTs of over 200 degree Fahrenheit!

So it transpires that the fans are switched on by a second ect sensor at the bottom of the radiator. However the fan operating temperatures preset by hondata are those that should be used by the block coolant sensor. The ect2 sensor operates about 20-40 degrees below the block temperature so the fans only kick in when the block coolant temperature is very hot and they will only come on very briefly.

In had to deactivate this second sensor and problem solved, cool engine and fans that come on at the right temperature. Idle flawless and power curve much better on the dyno all round. Similar issue with mpg recently when the default injector size for the dash was 3000cc giving me an average mpg of 1.2mpg haha.

If you are running a highly tuned engine you need good cooling, worth looking out for this issue guys, hope this helps someone.