AEM Coolant Temp Gauge Problem

AEM Coolant Temp Gauge problem....

The gauge has been reading incorrect so put it down to a faulty sensor. A replacement is around £44 with a plug, fuck that!

So ordered a new 1/8" NPT sensor and plug from EFI Parts http://www.efi-parts.co.uk/index.php?productID=125

Cut and soldered new plug to existing loom and it still read incorrect.

Purchased a new gauge and loom from a friend, cut and soldered the new loom and sensor plug and it still reads incorrect.

I've switched the gauge over to rule that out but again, still reads the same

Any ideas?

Probably stupid question, but how do you know it reads incorrect? Where is the sensor located, and how is it wired?

Ive got a GarageStar sandwich plate on the thermostat. The plug has 2 wires which I extended and soldered to the original AEM loom. The sensor would normally read around 190*F which is 90*C (OE gauge would sit in the middle at 90*C).

The reading would fluctuate either higher or lower than that while driving. With the new sensor it reads maximum hot (303*F/148*C) and when the car is stone cold in the morning its impossible for the coolant to be that hot.

Ive been told the scaling is different for AEM/Innovate etc so it could mean i need a genuine sensor

Get the right sensor. Typically they are fairly simple and linear, but each one requires a different calibration. You could check your old one using a multimeter though.

I would also check the sandwich plate and attachments for corrosion (resistance), or test the sensor somewhere else.