Coolant Fans won't switch off
 

Hi

I installed 2 eBay 80W slim fans a couple of years back and ran the car for a while then put it off the road for 2 years. I got it back out in March this year and since the. When the car geta warm the fans come on and stay on and don't go back off.

I had a coolant leak on the coolant reroute so as good practise I took it off changed the gaskets and put a brand new genuine Mazda thermostat in. Put it all back together and it's made no difference.

Ive also changed the green thermo sensor at the back for another one I had and changed the black fan switch at the front of the car.

The only other things I can think now are the relay controlling the fans or an ecu setup issue.

I'm running a DIY PNP supplied by Brain and haven't had any issues with it.

Please help it's frustrating me to death

Regards
Ronnie

what are the fan settings you're running

Hi

I'm not sure if I'm honest. Do I need to check the auto tune software I can't remember changing anything other than the settings that Brain mentions in his setup guide.

Pretty sure there is also a fan relay somewhere. These can operate in one direction and stick. If your fans are wited in parallel, this is another place to look. If they are switched from dedicated relays, then check your switch point in TS.

Thanks they are wired in parallel and I've located the relay. I'll try changing the relay and see if that works

or you could take all of 5 seconds to turn them on and off via megasquirt and know for sure if that's the issue before replacing anything.

One would assume that this has already been tested :)

but around here ...

I tried to change the relay for another 30A relay and initially the fans went off which was great. but I revd the car again to get them to come back on and they never switched off again.

What ampage relay should be used?

Tried to check auto tune and I can't see any settings to switch the fans off.

P = VI
V = 12V
P = 80W x 2 = 160W
160W/12V = 13.33A

Is the coolant temp dropping below the setpoint in TS? If it is not, the fans will stay on.

If the coolant temperature reading in TS is mucked (scale is off) that could hose you as well. Check out the online MS guides, make sure your sensors are working as expected in TS ...

based on how he refers to it (autotune) I'm guessing he has not a single clue how to even use megasquirt and would rather replace half the hardware on the car than open up tunerstudio, connect to the ecu, and go into fan settings to see what it's set at, which would take 5 seconds.
It should be under basic settings if you're on MS3

So the relay is fine. Ms shows temp steady at around 90 degrees C and fans cut in around 92 degrees then it appears the temp doesn't drop below 90/91 on the hinge on tuner studio

Thanks for the vote of confidence 18psi I've been around the forums for a while but the car has been off the road for 2 years and so I've forgot quite a lot about the tuning side of the DIY PNP. I'm using tuner studio.

90c is a bit low to have your fans turning on. Change it to 98c to turn on and then to turn off around 93c.

I'm on MS2

I don't know if MS2 have a fan outputs section, or you have to use a generic output. I know somewhere it is there though. What I assume is happening is you have a 90C thermostat and temps are hovering right above that, and so once the fans trip they never go off because it does not cool much below 90C.

That sounds right but I've looked all over auto tune and can't locate a setting other than under calibrate thermistor table it has the option of coolant temperature sensor

lars is right. I haven't used ms2 in years or I'd look it up for you. there is a fans settings screen though, you'll just have to really look around for it. ( I bet it's in one of the other sub-menu's that's not labeled "fans" like it is on ms3, so it might take a while to find it)

Ok I found output port settings then PM5 Warmup LED which shows the output channel as coolant and the threshold of 93.3 and Hysteresis 5.6 is that it?

I tried changing the settings to 98 and Hys to 3 and the fans still came I. Around 92 which indicates to me either I changed the wrong setting or the fan is been controlled by something else

Another strange thing is if you turn the car off with the fan then turn the ignition on the fan stays off until they start to run again assuming they reach a given temp and then stay on again

Sounds like the relay is wired to latch on once it turns on. If settings are correct then I'd start looking into the wiring. I personally just rewired the fan circuit with a new fuse/relays.

I don't think the port settings is what your'e looking for. Can you post a screen shot?
Because there should be TWO temperature settings there: one for when the fan comes on, and one for when the fan turns off. If you set them up backwards, the fans will turn on but never turn off after that.

Coolant Fans won't switch off
 

I use an MS2 but I'm at customers for a few hours and don't have my laptop with me. <br /><br />Give me a couple hours and when I get back will post a couple screen shots to help you out.

He is in the correct place. MS2 does not have a "fan" drop down menu, that was added for MS3. Basically you use a generic output to control when the fan turns on and off. Attached is a picture from my friends 99 DIYPNP showing what it looks like. OP needs to put his threshold to 97c and then the hysteresis to 5. What it is saying is to turn the fan on when coolant reaches 97c and then turn it off when it drops 5c less then the threshold.

https://www.miataturbo.net/attachmen...ine=1437748111

I guess I'm forgetting how old ms2 actually is :giggle:

i still run the cooling fan like that on ms3.

i use "fan control" to control the a/c fan.

Coolant Fans won't switch off
 

<p>Here's my TS screens and settings&nbsp;for the MS2E.&nbsp; You can convert to Centigrade.</p><p><img src="https://cimg4.ibsrv.net/gimg/www.miataturbo.net-vbulletin/1249x374/80-ts_fan1_ed3ec9b322ffa73a48897b3e09f538d5056f647a.p ng" title="" /><br /><br /><img src="https://cimg5.ibsrv.net/gimg/www.miataturbo.net-vbulletin/1259x865/80-ts_fan2_77317de62904892266c60a76c46475a8a700311d.p ng" title="" /><br /><br />&nbsp;</p><p>&nbsp;</p><br />I should add mine is an MS2E built by Reverent (MS Labs) if it matters.

then you need to reach out to reverant--it matters.

<p></p><p>I'm not the one with the problem.&nbsp; The OP does&nbsp; and just showing him where the settings are&nbsp;in TS (on my MS2 FWIW).</p><p>&nbsp;</p>

normal MS2 doesn't have a fan control setting. That's his custom firmware.

The only option I have is as per shuiend screen. I have no other option. I did try and adjust the settings but it still didn't turn the fan off.
The strange thing is that since I have been changing settings the fans will turn off when the ignition is switched off which is normal but when you turn the key back to put the ignition on the fans are now off until you Rev it a bit and get the temp up again.

It seems that whatever I change on tuner studio it doesn't seem to make a difference.

Is it possible my 2 x 80W fans from eBay wired in parallel are not enough to cool the coolant by 5 degrees and that's why the fan is not switching off?

The temp gauge on Tuner studio goes up to 93C then the fans cut in and then don't turn off. I changed the temp to 97 and it didn't seem to make a difference

still waiting for this...

:hatecat:

Hi Brain is this not what you need? That is what mine has in the same screen pas the one above. My temp is in degrees C.

What other settings do you need?

What happens if you set the fans to turn on at 97c, then restart the car. Are the fans on after the restart?

When I last tested no. They would turn off as soon as I turn the ignition off which is normal. But before they used to come straight back on when i turned the ignition to try and start the car. Now they stay off until the engine is started and then come back on after a few seconds of reving. They then stay on until you switch the ignition off

Have you checked any of the wiring? Is it all stock? Has the wiring been modified in any way regarding the fan circuit?

I used the original stock wiring and then used a guide from this site to wire 2 fans in parallel by extending wires and introducing a relay. There is a chance I wired them wrong and that is my next job to check against the diagram if I can still find it as it was years ago when I wired them.

Yeah I'd check it, especially if you added a relay. It sounds like when the fans turn on, the output that now turns on the fan motor is going to the input of the relay. So basically once the ECU turns the fan on, the relay "latches" itself on, and now the ecu can't turn it off. Only way to turn if off is to cut power from the relay (aka turn the key off).

I hope so Pat. I could really do with sorting this out and then moving onto my next issue. But I will save that for another day :)

Well sorry to resurrect this thread but just took the car out of storage since last time I posted and now I'm back on with trying to sort this out.

I think I have determined that it isn't a megasquirt issue as the fans cut in and then do go off when I turn the ignition off. The trouble is the fans won't turn off until the ignition is off.

That leads me to think it's the wiring and probably related to the relay. I have looked back at all the other threads and the only thing that stands out is that I didn't solve the yellow wire on the AC side I have these AC wires going to the 2nd fan and have no bridging wire over to the relay.

Then after messing around with the wires on the relay it appears that 1 wire is permanent live. One is live when the ignition comes on and one switches the fans on when put to ground.

When the fans cut in I can remove wires fro
The relay and I can get the normal fan to cut off. But no matter how many wires I remove the AC fan stays on and doesn't go off.

Anyone know how to wire the relay correctly?

Also just to check do they all have relays I can't remember if I added it or if it was already there.

do you still have the thermoswitch installed?


This is the right place to change the settings. But the thermoswitch will turn the fans on at ~93°C and off again at ~87°C.

This will override your MS setting if it's still installed.

changing to 98°C on with a Hysteria of 3° means it will turn on at 98°C and off again at 95°C.

Hi Brain,

Sorry to be dumb it's been some time. I can get back to the same settings but I'm not sure that is where I need to be. It just won't turn the fans off once they cut in.

But I'm not 100% confident with the wiring and can't find the original post where I got the info from to wire them in parralel.
Surely on Ms2 software the fan on and off is controlled by the temp sensor?

If you think I need to start in the software at the part above tell me straight and I will get the laptop back out. I just think it could be the wiring not the software as no matter how long you leave the car running with the fans on it won't switch off the fans
Regards

Just to further elaborate
My car has a relay on the wiring which I guess I added. I need to tell you at this point that both wires which went to the AC fan are wired to my fan. I know reading past threads it says just splice one and run it over to the fan 12V and cut the other. Mine isn't like this!

Could that be it or would o have put the relay in to allow this?

Sorry to be very noobish but it's been years since I did it and I only get it out every summer so I can't remember what I did.

Also yes I have the thermoswitch still on the car and i assume working as I already tried swapping it with another just in case

Eureka!!!

Brain you legend. Changed to 98C and 3 as you suggested and the fans are cutting in and out.

Thank you my friend.:)

keep the thermoswitch unplugged so long as MS is controlling the fan.

I'd use 93C and 6C. for on/off.

I will have to try that another day but just to confirm is it the sensor at the back of the engine green in colour ? (I have a coolant reroute which puts the green sensor at the back) or the one at the front which is black and I believe is the fan switch?

It's. 1.6 1991.

I can't work out why it wasn't switching off before other than the temp was set to 93.3c and the other bit to 3.8 but not sure if that makes a difference.

Also if I set it for 6C it will take a lot longer to switch off which I'm worried it won't. But hey I will give it a go