Just went out for a little tuning drive.

Coolant temp readings stayed around 194-196F moving when running 60-70mph. Stopped at a light coming back went up to 200. Back to 196 as soon as I started moving again.

There is more movement than I would like in the gauge between 195 and 200, but I think ...

I am still using the dme relay to switch on the aftermarket control hardware, so that is still present. I would think if you gave the switched power as the control signal it might work but everything I can find starts the clock on power on, not off.

Yeah another reason to go back to the factory fans. I did not want to cut the plastic shroud to adapt the new fans (glad I didn’t).

Right now I don’t have the shape of the factory shroud at all.

I think the factory fans will make a big difference. I do have an 80 degree thermostat now and my fans ...

Yeah as soon as I start moving the temp comes back to dead center or just below (so abt 90 deg) sitting at a light it goes up probably 3-4 deg. It does not get as high as it did before new thermostat (right under 100deg).

Wiring was shot and one resistor broken. I wanted to use microsquirt canbus + arduino to control a pwm based system with full variability.

Needed to get the car running and driving so right now the fans are just all on or all off. I was going to use aftermarket fans (those are on right now) but ...

I have converted this car to microsquirt engine management. My understanding is the extra electric pump and relay setup for the coolant flow to the turbo is independent, but on the wiring diagrams it does pass through the dme, among other places.

I wish MS had an extra output that I could use to ...

Yep - first time was easy as engine was on a stand. In car is a bit different!

So reporting back that everything is back to normal, but my aftermarket fans are not pulling enough air.

I am going to remount the factory setup but control the new relays from microsquirt. Right now it will just be ...

As promised did some sleuthing to see what was going on inside the cooling system. Pulled off several lines so I could check flow everywhere. Pulled thermostat (ugh!) and tested it.

Lo and behold - thermostat will not open in boiling water on stove (80C version). Makes perfect sense with the way ...

BTW…interestingly I had no leak there, apparently it may have been just loose enough to keep the system from pressurizing.

Well I may have found the issue. Loose clamp on the hose from the head to the heater valve…tightened and let it warm up in driveway in got to just a hair above halfway revving at idle. Will drive it tomorrow and see if it behaves!