Temp guage goes straight to hot

TREVO123 · Post by **TREVO123** » August 21st, 2007, 8:29 pm

My temp guage as soon as i turn on my ignition goes straight to hot, then i ungroudned this one thing now the guage doesnt work, but as soon as i groun the wire again it goes to max heat, Any clues on this would be appreicated,,

sorry if wrong section

TREVO123

PATDIESEL · Post by **PATDIESEL** » August 23rd, 2007, 3:15 pm

The temp guage works on voltage current. Meaning that as the water gets hotter the more electricity flows through the sensor and the guage actually just responds to the voltage. The guage face translates the needle into a temp range you can understand.
Thus, it sounds like you have a bad sensor. Try replacing it and see what happens.
Ps- there are three temp sensors on the K8 and KL-DE, 2 on the ZE (unless you added the third). I cannot remember which one is for the temp guage, but one of them controls the guage only. The others are for the collant fan and the ECU.

TREVO123 · Post by **TREVO123** » August 23rd, 2007, 4:11 pm

It is on a BP!, so there is a Sensor and a Sender...ive looked at the wiring, its done this ever since i blew a head gaskit, then replaced it.. so i dont no what the hell is going on, i can move this wire, and it goes straight to hot, but if i unground the wire the guage jsut dont work!

umcamara · Post by **umcamara** » August 25th, 2007, 11:57 pm

I read a similar post to this, but I don't have a link to it. The guy had done a BP swap and was having the exact same problem as you.

Not entirely sure why, but the BP's temp sensor's cold point registers as hot on the MX3's dash cluster. I think this is a normal problem with the swap.

I can't remember what the solution was, I believe it was to swap in the coolant temp sensor from the B6, but I could be wrong.

Volones · Post by **Volones** » August 27th, 2007, 10:23 am

I would check it with a thermometer to see what the temp actually stabilizes at, although most likely it's not much more than the thermostat is rated at. That will reduce your concern about your car overheating all the time.

Then, if the BP sending unit is using a different voltage range than your gauge , either replace the sending unit, or put a variable resistor inline so you can reduce the voltage until you get the proper reading. Obviously you would want to match the gauge reading to the actual temp you're getting from the thermometer, and not just make it look nice. Once the gauge is reading properly, you can take out the variable resistor, measure the resistance, and wire in a permanent one of that resistance. Your gauge should then work consistently, and you can tell all of us what resistor to use and be the hero.

Personally, I'd use the sender that matches your gauge, and save a lot of time.

Vol

TREVO123 · Post by **TREVO123** » September 5th, 2007, 3:14 am

Well its not the coolant temp sensor. I can say that much,still does the same old thing..