Fan issues with the 94 and the new KL36 ECU



  • I have a 94' GS with a KL31 swap that previously was running a KL86 ECU and KL02 VAF on.

    I have just changed the VAF back to a JE50 and installed the KL36 ECU. The car runs and drives GREAT, big difference over the KL86 ECU. But last night I noticed I was running a little warm and that my fan relay was not fully engaging the relay is clicking and the fan will engage for a second and then off and repeats. After a little research this morning it seems like the MX3, MX6, 626, and Mellenia all share the same coolant temp sensors and fan switch, but all have different fan relays.

    My question is do you think I need to change the relay to a MX6-626 or mellenia relay to get it to function properly?

    The car does have the extra coolant sensor run already.

    Thanks for any help.



  • First off is your fan acutally working?

    Are saying that if you run the stock ECU the fan does work properly, but when you run the ZE ECU it stops working?

    Is you 94 MX-3 OBDI or OBDII? How many yellow plugs go into the ECU?



  • I had the same when I swapped my ZE in and it turned out the fan had just stopped completely, when I looked closer where I had taken it apart the contacts were dirty / faulty in the connector block, ended up just hard wiring it and removed the connector and its fine ever since,

    considering adding a second fan currently as the ZE makes more heat in the engine bay and the rear bank is overheating a little so also adding some heat tape around the down pipes to get spome more heat out the engine bay and dispersed underneath



  • So I guess the 94's is supposed to have a different harness than the 92-93's here in the US and the KL36 is not even supposed to work with my distributor. Well that was false. from what I know is that US guys have issues with the cooling fan either not working at all or continuously running all the time.

    My car the fan was not running properly the relay was clicking and the fan would run for a second and shut off then do it again over and over. I already had the 3rd coolant sensor run so I cleaned some of the connections and it seemed to be working or so I thought. Now the fan comes on when warm like it is supposed to but it is not cycling. Once it comes on it stays on, so I have a new relay I am going to plug in and see if that fixes it. The relay could be sticking I guess.

    I dont know, other option is start changing out the coolant sensors one by one.



  • RULE OUT THE RELAY
    If you are OBDI bridge gnd ten pins in the diagnostics box. This may or may not turn your fan on depending on if you have your TPS setup correctly. If it does not mark your tps up with some paint so you can put it back as it was then adjust it until your fan comes on. Then adjust it back until it goes off.
    If it goes on and off then you know the relay is working and that is not the problem. For more info do a search on TPS adjustment.

    TEST THE TEMP SENSORS
    If you have access to a multimeter you can measure resistance change across the Temp sensors from cold to hot. Or if you have spares just swap them out.



  • @b05fe5f497=ukmx3admin:

    RULE OUT THE RELAY
    If you are OBDI bridge gnd ten pins in the diagnostics box. This may or may not turn your fan on depending on if you have your TPS setup correctly. If it does not mark your tps up with some paint so you can put it back as it was then adjust it until your fan comes on. Then adjust it back until it goes off.
    If it goes on and off then you know the relay is working and that is not the problem. For more info do a search on TPS adjustment.

    TEST THE TEMP SENSORS
    If you have access to a multimeter you can measure resistance change across the Temp sensors from cold to hot. Or if you have spares just swap them out.

    I am OBDI, I would not have thought the TPS would have anything to do with the fan coming on or off. I will play with it tonight. Thank you for the input.



  • The TPS is NOT your problem.

    What I said was that when you set your TPS while in DIAGNOSTICS mode it will turn the fan on and off.

    This will tell you if the relay is working.

    DO NOT alter the TPS unless its in DIAGNOSTICS mode.

    Hope you understand.



  • I understand, I just didn't even realize that it did that. Thank you



  • So the relays are working and functional. I think I may have narrowed it down to the 3rd coolant sensor or the one on top. My manual sayes it should reed 1.04 ohms but it is reading like 7.04…



  • So the relays are working and functional. I think I may have narrowed it down to the 3rd coolant sensor or the one on top. My manual sayes it should reed 1.04 ohms but it is reading like 7.04…



  • Did you take the reading when hot and cold?

    I normally do them all when cold and then when hot, then its easy to spot the broken one as its way different to the other.

    Seems like you sorted it though, let us know.

    If you know someone with an MX-3 you could borrow theirs to test before you spend money.



  • yeah, thanks for the help.

    The temp gauge read cold, but the engine was still warm from running it. I will test it again this morning. I think a new one is like 6 dollars, but I know a couple people who probably have one or two of them laying around. I am hoping that this is all that is wrong. But I guess having the fan constantly running is not the worst thing in the world.


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