Gen 2 Cooling Fans Not Operating

Discussion in 'Busa problems' started by AndySV1K, Aug 5, 2017.


  1. AndySV1K

    AndySV1K Registered

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    Hi,

    I'm after a little advice or thoughts on a new problem I've recently discovered.

    My 2015 Gen II cooling fans are not coming on and on a recent trip to Europe it was overheating when riding through a city centre (Right into the red with the warning light on). I didn't know the fans weren't running until i got home and started looking for a problem.

    Now the bike has very recently been remapped and I can't recall whether the fans have worked since then or not but I want to check as much as I can before going back to them.

    Firstly, the fans are fine, they spin free and i've run external 12v to both and they spin up just fine.

    I've checked both 15a fuses and they are good too.

    Lastly i directed my attention to the thermo switch, which from what I can gather is the one on the rear left side of the block (?) When disconnected it throws an F1 code. I've worked out resistances of this to fool the ECU. It was 2.7k reading from the thermo switch with engine cold, so I put resistors across the connector, gradually lowering resistance and the temp gauge was responding accordingly. I can get the temp gauge to rise to around 3/4 which should be way above the fan cut in temp but still nothing happens.

    The only thing I have to check now is the fan relay but I can't seem to find info on where and what this is.

    There is a relay next to the fuses but when unplugged the fuel pump doesn't run so i assume it's for that.

    Could anyone help with locating and testing of the fan relay please?

    After this, if the relay tests out okay then I can only assume someone screwed up when squirting new 1's and 0's into my ECU during the remap.

    Thanks

    Andy.
     
  2. David Offor

    David Offor Registered

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    I've got the gen 1 and I know that the relay that controls the fuel pump, also has something to do with the fan, never really looked into it because I've never had a fan issue.
    I know another guy that fitted an aftermarket temp sensor and it wasn't bringing on his fan until far too late, it's the one that screws into the cylinder head on the gen 1s, maybe your temp sensor has given up the ghost?
    Good tests with the resistors btw, I wouldn't of thought of that.
     
  3. GIXERHP

    GIXERHP ok, ok...just a wee bit Irish... Donating Member Registered

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    Check the coolant level, if its low,, the air gap will cause the the fans not to come on,,
     
  4. AndySV1K

    AndySV1K Registered

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    Hi David,

    Thanks, i'll look into that relay a bit deeper to see if it does control the fans too. I've been trying to get hold of a service manual but the website everyone seems to link to doesn't appear to have any links that I can click to view or download. It just lists the contents of the manual.

    The temp sensor has a resistance reading of what I would expect when cold (2.7Kohms) and if it's disconnected the bike throws a fault code so although I haven't run the bike to watch the resistance actually change, I do think it's working okay. I will pick up a potentiometer from work today which will allow me to really easily adjust the temp reading sent to the ECU which will help with further testing.

    Andy.
     
  5. AndySV1K

    AndySV1K Registered

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    Hi Gixerhp,

    Coolant level is mid way between min and max so should be okay although i don't know if there could be any airlocks. However as long as the bike is moving, engine temp is no issue at all so i'm guessing its all flowing as normal.

    But also, how would coolant level stop the fans operating? From what I can gather the temp sensor in the cal head reports back to the ECU which then decides when to operate the fan relay. So as long as the temp sensor is reporting back okay then it should trigger the fans regardless of coolant level? I could be wrong of course as this is just what i've been discovering over the weekend of playing around with it!

    Andy.
     
  6. GIXERHP

    GIXERHP ok, ok...just a wee bit Irish... Donating Member Registered

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    The air usually gets trapped at the thermostat housing, when the bike is cold remove the radiator cap and check what is in the radiator. What you see, in the overflow, is not always a a tell tale sign.
     
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  7. David Offor

    David Offor Registered

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    If you do have an airlock, a faulty water pump, might not be circulating the coolant, that's a possibility, it could explain the fact that you are ok with air passing through the rad at speed but then overheat at standing, of the fan switch isn't immersed in coolant, it will always read cold, so no fan on.
    Just thinking of all the components in the cooling system, good call on checking with the rad cap off.
     
  8. AndySV1K

    AndySV1K Registered

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    Thanks for the reply chaps. I will definitely check the rad cap to see what's in there.

    The only thing i'm still not sure on is how that would affect the fans? As it appears the temp reading is taken from the back of the cylinder head and not the radiator and it appears to be working normally, surely this means I have good circulation? When it was overheating, it immediately cooled again when I started moving so cooler water in the rad must be flowing into the block to affect the reading being sent from the ECT in the engine.

    I spoke with the garage that remapped it yesterday and while initially they were a little defensive about me questioning whether the fans could have been inadvertantly altered during the remap, once I explained the process I had gone through to fault find, he was much more helpful and we went through it all in detail and were trying to think of any further checks I could do. I will keep exploring but suspect I may well end up back there for them to pull the program from it to check it over.

    Oh as an update in case anyone else needs the info, I found the relay for sure. It's next to the fuses but isn't the big one that runs the fuel pump. It's a smaller oblong relay mounted with a rubber onto the same bracket as the fuse box and has four connections going to it. I was able to test both that the relay was working fine and also that shorting the load side of the relay started the fans up.

    Andy.
     
  9. David Offor

    David Offor Registered

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    Good to hear, that the shop is being helpful.
    Just thought I'd mention the thermostat too, as a possible fault, restricting circulation, if faulty but your problem does sound more electrical than coolant.
     
  10. AndySV1K

    AndySV1K Registered

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    Hi David,

    Thanks, I will still check what you suggest as I want to rule out all possibilities before taking it back as it means a day off work and 250mile ride.

    I appreciate all the input :-)

    Andy.
     
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  11. dave s

    dave s Registered

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    Sounds like they turned off the fans
     
  12. Cantab

    Cantab Registered

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    Im thinking the same its been flashed.
     
  13. AndySV1K

    AndySV1K Registered

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    Yeah, exactly what I suspect. Real bummer as it's gonna be a day off work and about 250 mile round trip :-(
     
  14. turbojonny

    turbojonny Registered

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    Frusterating. I have a flasher and it's just a click of the mouse. It might be cheaprr to buy an ecu flasher and have the guys who did your map send you the file. You can then pull up the map, turn the fans on and flash it.
     
  15. AndySV1K

    AndySV1K Registered

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    I won't get a flasher for this as I paid for it to be done so want to let them sort it out, but I may actually buy one long term so I can connect up. Where's the best place to get one?

    Andy.
     
  16. turbojonny

    turbojonny Registered

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    Boostbysmith is where I got mine.

    I thought about this more last night. I don't recall that the fans can be shut off. I think the temp at which they turn on can be changed, but I don't think one can shut them off fully.
    If I have time this morning I'll open up my map and take a look.
     
  17. keene757

    keene757 Registered

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    Try resetting the ecu. Disconnect the battery and then reconnect it after about 5 mins. I would unplug the ecu too while battery is disconnected. This happened to me and i reset the ecu and it worked fine afterwards. The ecu sends the signal for the fans to cut on.
     
  18. turbojonny

    turbojonny Registered

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    Hi Andy,

    I got out the laltop and checked ecu editor for the ability to turn off the fans. They cannot, only the temp can be altered.
     
  19. shade

    shade Registered

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    but if the temps are altered to turn on very high they will never come on.
    IE what if someone typo'd 400 degrees
    fans would never kick on. We need to see what the ecu file shows
     

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