Just a random thought. Fan is Ecu controlled, so ktm knowing about all the head gasket issues should do an update on the PCM to lower the temp at which the fan comes on. Seems like a super simple fix. Drop the fan temp on time to 90 deg or something. Maybe that would aid in the longevity of these engines. I'm guessing it's a simple switch in the code to swap out to a lower number. Maybe chad wells can step in on this and comment
Chris The Welder
New Member
Sounds reasonable. On my TL it was a temp switch. Oem was set to 215 f. I found one out of a Mazda that was set to 190 f. World of difference.
Treachery
Moderator
Hmm...wonder if one of our resourceful members (or vendors) might do the legwork on this... I'll order up!
Cts (coolant temp switch) should be a certian resistance varying according to temp. Once the resistance reaches a set value the ecu triggers the cooling fan relay on. I'm thinking it should be easy enough to see what that resistance is by running up to temp and watching with an ohm meter. Would be simple to fool hhe Ecu with adding in a resistor to drop or raise the actual reading. Personally I wouldn't mind the fan coming on at the halfway temp mark. I'll be bringing my meter home with me this week and doing some testing. I'll report back with what I find. I may be on to something good.
I dont think it will be as simple as finding a different cts. The wiring diagram shows its just a simple 2 wire resistor. Finding the readings for when the fan cuts on should be very simple. Then its just a matter of calculating what resistor added to the circuit will fool the ecu into turning the cooling fan on. Ill be starting on this tommorow night and once i get some readings and calculations done I will report back. Resistors are about 25 cents to purchase so this could be the cheapest fix to an overheating issue to date,
Also so looking at the diagram the temp display is spliced into the circuit. If you add the resistor before the splice your temp display will be inaccurate as well. So probably finding the correct resistor and adding it close to the PCm connector will be the answer. That way you will get the correct temp reading on your display.
Fasteddy
Member
The resistive representation of temperature being read by the ECU does much more then control the fan. That is surely one of the inputs into the mixture algorithm etc.
If you want to change the operating point of the cooling fan the best way would be to add a solid state thermostatic control and have it control the fan relay instead of the ECU.
If you want to change the operating point of the cooling fan the best way would be to add a solid state thermostatic control and have it control the fan relay instead of the ECU.
I agree that yes it does play into the mixture algorithm but I'm wondering how much difference dropping the fan on temp by even 10 degrees would really make in that table. Most of the lookup tables I have viewed the temp ratio is very wide and did not affect fuel mixture. Fooling the Ecu into seeing the engine being 85 f instead of 70f should t be a real big deal. The reading will inversely increase to the point of in the algorithm to turn the fan on 15 degrees under the actual temp. Ideally a thermostatic switch to trigger the relay would be ideal. Simply removing the Ecu out of the picture and having that thermistor close circuit at your ideal temp would prove easy as well. But my question is would removing the Ecu from the really side cause an engine light?
ideally having ktm step up to the plate and changing the programming so the fan cuts on 15-20 deg cooler would be the best solution IMHO. But I don't have any ability to follow through on that type of request. Possibly someone like Chad Wells would have an idea on how to channel this to the proper people?? I think it just makes complete sense to adjust it lower. Possibly reducing or even preventing repeat overheating failures.
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Why not just install a "on/off" style switch? My R1 fan use to kick on at around 215 degrees so, I just installed a switch from Radio Shack that has a tiny LED in it, that way I don't mistakenly leave it on. Thought I'd throw another option out there...Hmmmm,,,,don't know why I haven't done that yet....
That would work, but there is always the idiot behind the switch that may forget to even turn it on. Especially for those of us who race the bike, we have enough to concentrate on and having to take charge of the cooling fan while racing is just one more thing that would distract
from what you are doing. Ideally the fan should be automatic. But certainly if you wanted to, easily bypassing the computer control would be simple with a switch
I haven't looked at wiring diagram but it shouldn't be affected. Fan still operates normally,,,,but you can flip (LED) the switch when you may think it's needed...traffic, pit lane....etc
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psych0hans
Member
My fan's conked off as well last week, will be getting it replaced under warranty.
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