Coolant temp sensor

I need year--make--model to look up wiring info?

it could be that then wire to the sender unit ( not sensor as it is different ) is loose or shorting out on the head
there could be an air lock in the cooling system that is allowing spasmodic water flow passing the sender unit and sending the gauge to hot
if there is no coolant around the sender unit ,it will read cool and and flush will send it hot until the coolant subsides and then it will read cool

Check the wiring to the temperature sender unit. Sounds as though the wiring is earthing out some where.

check that there is coolant or fluid in the radiator as a coolant temp sender cannot read air as it is a vital part of the injection system for the ecu to know if the engine is cold and if sender relays no reading it is telling the ecu that it needs to ritchen the fuel mixture (possibally the reason for the fast idle) to get the engine up to normal operating temp as soon as possible.it you live in a really cold climate a thermostat that is jamed in the open position will cause it a long time to reach a warm reading. hopefully it is just the sensor wire off the coolant temp sender and by replacing it will return ever thing to normal

1985? Samurai? (no vitara) NO YEAR makes the real hard.!

the dash guage is but a toy and not and instrument.
if fact it has no numbers on it, no 180F. markes there....so....
the gauge is reading hot because the 1 pin 1 wire, sender wire
for the gauge is grounded out, remove this wire from sender
and the guage, must go to low.
btw here is the G16 being gauged, FULL HOT.
the gauge and sender tests are in the FSM. read that.
http://www.fixkick.com/sammi-stuff/index.html

here is the G16
the no num gauge.
http://www.fixkick.com/Cooling-engine/new195F-reading.jpg
here is the best way to measure engine heat.

http://www.fixkick.com/Cooling-engine/rad-top.jpg

see how well the RAD works, see this. big drop !
http://www.fixkick.com/Cooling-engine/rad-bottom-left.jpg

on the G16, we test the guage like his.
yours is near identical.
http://www.fixkick.com/sensors/tests/Guage-coolant-test.html

on you car pull the sender lug. stuck H.
guage drop. to L, sender bad. or WRONG sender (common)
guage at H, then follow wire, from it to harness, ahhh, all cut up
and bare and hitting ground, bingo.

rare car, how cute. its a 1.3L what ,its EFI , not carb.
the ECT and guage are not related at all.
each has its own sensors.
dont use a torch you will kill it, use hot water man.
please..................
the guage is a 1 wire sensor. it has a different resistance profile than
the EFI Engine coolant sensor ECT. is a different sensor.
the EFI sensor 2 pins, reads 300 ohms hot and about 3000 ohms cold.
hot is 200 F, not torch 2000f hot. for sure. never exceed 212f on any sensor ever.
I must presume you are futzing the wrong sensor.
first off, I will cover just the gauge, and the fsm is on line
for free, and you can read the guage tests. they are simple simon,

see here, see the books?
http://www.acksfaq.com/sitemap.htm

im and expert on the sidekicks but they are close to sammi.
infact its and evolutionary change.

the guage sender is sold everywhere, and has unique spec.s.

ill use rockauto.com so you can see them all. sold.
first off the guage has very low resistance,as does the gauge sender
that is because is thermal acting the guage gets hot and the needle moves, very very crude this. very very old school stuff.
they did the bs until 1995.
chapter 21. electrics. sammi.
page 21-12 , fuel level meter and guage.
direct link to that here.
http://www.acksfaq.com/86-87_410_FSM.htm
see that?
pdf page 145
use a 194 lamp and ground the yellow wire as shown
meter goes upscale the meter is good.
now the sender.
is RTC reverse temperature coeffiecent, that is
hotter = lower ohms. pdf page 146 left.
122f is about 155 ohms
176F = about 50 ohms
212f (boiling water) is 28 ohms and gauge shows HOT.

that is it for the 1 wire sensor.
stupidly they say to put sealing tap on threads,
dont, or you get an open ground. amazing...
tighten firmly or risk cracking the intake. its a tapered British thread.

now the rock. the right sensor for JUST the Guage , coolant.
http://www.rockauto.com/catalog/raframecatalog.php?carcode=1271135&parttype=4748


a real FSM
and a real source of parts, 1 post.
all for free,

maybe faulty guage ?? remove wire from sensor and earth it on engine gauge should rise fully if not gauge is faulty?????? ps turn on ignition when checking.........

find temp sender turn key on and disconect wire from sender and earth it if guage moves to hot sender falty, if not guage faulty, or broken wire,or no power to guage

U are talking about two different sending units, one is the Engine Coolant Temp sensor, the other is the temp guage sender, sounds like you have a bad thermostat, if the engine doesn't reach the proper operating temp it will set a code for the engine coolant temp sensor, and the guage will not move or move very little, replace your thermostat and both problems will go away.

replace thermostat, this fixed my car, cooling fans keep coolant below temp guage parameters.