I am having slight problem with ZE ECU PLEASE HELP

[RobertoCarlos]

I have a 95 mx-3 with a klze engine. I have been running the 1.8 ecu but just got the ZE ECU today amd it definetely makes a BIG difference. The only thing is after my car gets about 60 degrees in temp radiator fan comes on and stays on. Is it because 92-93 use 3 temp sensors and 94-95 use 2. Its a kl31 ecu and I was also wondering if ZE ECUs can go into limp mode.

[Nd4SpdSe]

its definitely the fact that you only have a 2 sensor '95 mx-3, i remember Lazzyie mentioning it to me before i purchased mine

[timpronk]

Just a thought but its prob not such a bad thing to have the fan going, the ze runs a little hotter anyway due to higher compression, as long as your alternator is up to the task.<p>Maybe you could adjust the tps a bit to make it shut off.

[lazzyie]

no there is no limp mode, no your fans will not shut off *ever*, no it doesnt do anything, mine are on when the car is on all the time

[AbRasiF]

Anyone knows a way to stop the fan from always running? Splice a wire to fake that you have 2 sensors??

Etienne

[lazzyie]

No there is no way to fake it out. You would have to actually figure out which pins on the ecu go to the sensor in question and run a new set of wires to a new sensor.

[AbRasiF]

Lazzie: I don't get it then... everyone that has a 94+ MX-3 with a KLZE and it's ECU has this problem?

[Zoso124]

I would think so, if someone can give me a few shots the wiring diagram for the 94-95 ECU I can tell you how you could wire it up differently.

[IanL]

I've had a look at the MX-3 and MX-6 diagrams in Chilterns, and it seems that the MX-3 has a single stage cooling fan, but the 2.5 litre cars have a two-stage fan.

I'm guessing that, after the engine starts, the KLZE ECU keeps the first stage on, and only switches the second stage to keep the water temp within limits.

ECU terminal 3L controls the MX-3 fan relay, and the 2.5 litre first-stage fan relay.

If you want to change your MX-3 to the 2.5 litre configuration, you would need to fit a two stage fan, and the two second-stage relays (why two?), and wire them to ECU contact 2P. But if you aren't overheating or overcooling, why bother?

[bubba_03]

If you take the wiring harnes out of 92-93 GS and put it on a 94+ would that prevent the fans from staying on constantly?

[IanL]

The '93 models have an additional Water Thermosensor (Fan) which connects to 2G on the ECU. If your engine has the additional sensor, but the harness hasn't got the wire, you could just run one wire to connect it up.

I wouldn't be too sure it would make any difference to the continuous running of the fan, though, bearing in mind that later MX-3s still have the single speed fan, without the extra sensor, and the fan doesn't run continuously. I may be wrong, but my guess is it's bound up with the two-speed fan.