So I'm here trying to ask the same question again. Any help would be great.

Earlier I sent my Prosport gauge because it was reading 15 degrees high. Prosport themselves claimed that their sensors was working fine but sent me a new set. However I tested the new set and it was reading a different resistance value (68F at 1220 ohms). Installed it back in the car but it still isn't matching my tunerstudio values. The Prosport gauge is mounted in the upper hose.

CLT values:
14F 9250
71.6F 2320
176F 330
biased resistor 2490

Using GM iat sensor
-40F 100700
86F 2238
210.2F 177
biased resistor 2490

This stuff is pulling my hair and the noobness of me can't figure out why. I'm running Bp6d vvt swap into 95 miata with I/H/E and flywheel. I got a friend to do the project but ended left me hanging.

 

I have attached my tune hoepfully someone can give me some advice. thanks.

 

Put it in a pot of water along with a known good temperature gauge (digital meat thermometer or similar). Take three readings on the way to boiling, then do your OEM sensor too. Use the data to figure out who's right and who's wrong.

(Here's a hint: The Prosport gauge is wrong)

 

thanks I'll try that out. Would taking the rad cap off and getting a reading from there be accurate at all? Should I even try it or don't bother?

Also when I get all the datas in ohms, should all of the resistance numbers read the same? Or do they vary differently from other manufactures?

 

My gauge is wrong too. I trust the ecu gauge more so I plan to add a resistor somewhere to make my external gauge correct again.

 

Don't waste your time with those gauges, AccuTech gauges are relatively cheap and are extremely accurate in my experience. These are available from a number of vendors on here.

AccuTech? Stepper Motor Gauges

 

So I've tested it with a thermometer beside it. Poured hot water and wait for it to settle. My thermometer is reading 105f while the gauge reads close to 130f. Found my answer thanks!

 

They will typically differ.

There are several different standards for the calibration of value to voltage in automotive-style temperature and pressure sensors, so it's not reasonable to expect sensors from two different manufacturers to yield the same resistance value at the same temperature. This is why Megasquirt has the sensor calibration function in the first place.

 

Update. I a hoping someone can solve this with me.

I tested the prosport again the other day and wired the to power straight to the battery and my gauges are a lot more accurate than previously wired to the radio.

Do any of you guys have this issue? Could it be that my ground or wiring not getting the amperage delivered to these gauages?