DIYPNP Coolant Temp Problem
 

I've been playing around tuning my DIYPNP for a bit now and I'm having trouble with the coolant temps. The car warms up as normal but then gets to 200 degrees and the fan turns on. The temperature won't go below 190 so the fan never shuts off. At cruising speeds on a cool night I'm showing temps 210-220 on average and never below 200. Hence the fan stays on constantly. Full of coolant. Gauge on the cluster reads as it did normally with the factory ECU. Also, it's a new sensor. I have checked the coolant temps at ambient temps as well. Car hasnt run today and is showing coolany temp of 76 and its 70 outside so it seems close enough. Are the temps really that high and should they be? Also the temp gauge on tuner studio varies ALOT it twitches about + or - ten degrees. Not sure if that means anything. Not sure what to do going forward and would appriciate any input. Thanks

did you calibrate it correctly?

if ambient is 70 and coolant temp reads 76 that is off, not close enough. calibrate it.

I did calibrate it using the settings normally used for the miata. I also tried to figure out if those settings were incorrect and tested a coolant sensor at 32 68 and 212 degrees. It was correct based on the resistance readings I took.

if youre seeing 220 in TS, your dash would be at 12 o clock; that's not the case, correct?

Your virtual coolant temp gauge shouldn't twitch around. That's most likely a sign of a loose wire or other loose connection such as a marginal solder joint. I would inspect all wiring related to the coolant temp sensor and try to find a fault.

If you have a relatively stock cooling system, then it is not uncommon to see coolant temps in the 200-210 range once warm. The gauge in the dash will read normal to well over these temps--it really does not start to move until well after an over heat situation.

I've seen up to 230 in TS with dash at about 10 o clock.

I'd redo the calibration. just use the RX7 CLT (s4 & s5)

Alright. I'll check this wiring thanks. Cooling system has automatic radiator and an upgraded fan. Should I not have the fan kick on til 210 then? Thanks

I tried that as well per a tutorial thread by you. Same results.

I would call that a stock-like cooling system. Without mods air flow mods (ducting, shrouding, venting hood, etc), the Miata relies heavily on the radiator fan. I like to turn it on at 190 or sooner.

You may need to check your cooling system for proper functionality. The radiator may have a clog or your aftermarket fan may not move all that much air.

Stock fans often work better than aftermarket.

Mine comes on at 200 and goes off at ~195 IIRC.

I changed to a 180*F thermostat and a 52mm radiator, too.

I don't believe the problem is in the cooling system itself. With the factory Ecu, the fan cycles a little after sitting at an idle on a hot day, but doesn't turn on much beyond that. I also just recently installed the fan to see if it would help. Got it for free so what the heck. I'd like it to turn on at 190 as well, but no matter when it turns on It's still gonna be on all the time. Cooling system works and has always worked great on this car.

I was just trying something new as I got it for free.

Hey guys so I don't mean to high jack this thread but it's relevant so what if my coolant temps in TS show normal high 180s and highest being 192 on my turbo NA6 but my dash temp goes and stays at the one o clock position.. Headgasket ?