[s-cars] Temp Gauge Not Working

[Dave Forgie]

Mike:  I believe what you are likely experiencing is a failed
multifunction temperature sensor (MFTS).  It is located very near the
thermostat, under the intake manifold and supplies signals to the
temperature gauge and the ECU (this is the important part since this
also changes the boost map). The MFTS  is the one with the big connector
(4 pin) on the water manifold.. The replacements are 3 pin because they
use a different system than the original 4 pin units.  Go to Scott
Mockry's website at:

http://www.sjmautotechnik.com/cooling.html#gauge   and all will be
revealed.

Read through the details very carefully.  Especially the bit about not
over tightening.  You will need a deep 29 mm socket  to do this job.
Takes about 10 minutes. Start with a cold engine as you will want to
plug the hole in the water manifold with one of your fingers when you
get the failed one out so you don't lose too much coolant.  I did mine
in my street clothes and didn't get dirty.  Lost about 250 mL of
coolant. (Which ends up on the ground - which means you should dilute it
with lots of water so a dog or cat doesn't die from licking it (it
tastes sweet - don't ask (previous oops))

Makes a big difference. I thought is was a wonky gauge or wonky
thermostat.  Wrong. Thermostat helped and gauge was fine - MFTS was F'd.

Dave F.