Jumping Temp Guage

[Red_85_AE86]

I did replace the temp sensor ( the one in the middle of the 3 sensors with 1 wire )


A) The guage jumps from mid to overheat and will stay there for a bit and jump back, chill there for a bit ... than go to overheat again ( this is when i have the temp guage plugged in )

A) The guage jumps from mid to cold and will stay there for a bit and jump back, chill there for a bit ... than go to cold again ( this is when i have the temp guage unplugged )

What else can it be ?

[Flashmn]

Grounding problem in the gauge.

[Red_85_AE86]

What is the closest wireing junction that would have grond on it .... does anyone know ?

Is there a AE86 PDF manual on electronics and sensors ?

Can i just ground it by taking a wire and grounding it to the block ?

Guess i will have to give it a try ?

[Red_85_AE86]

delete

[Hemi3TC]

I had the exact same problem (A) with a 82 rolla. I figured it was either an air pocket in the cooling system or a bad connection in the instrument panel. After a new radiator to replace a leaker and a new temperature sender and thermostat.

I took out the instrument panel checked the temperature gauge, it was OK. Then cleaned the plug connectors and terminals with a contact cleaner. MG Chemicals super contact cleaner is what I used. 23 years could be oxidation on the terminals.

Before that I had jacked up the left hand side to clean up some rust under my car. So maybe that purged some air bubbles. But anyways check for coolant leaks.


You can ground it to the block, intake, lifting eye, but that will redline the gauge. The FSM says to use a specific light bulb #?? to test the gauge. But in the FSM 47 ohms is about 185 F for my 82 rolla. So I had one (47 ohm resistor) in there and the gauge did not move while testing. Weird.

Also check you body grounds. I cleaned them all up too. Since the problem is intermitant and every bit helps.

Also your problem (B) is strange. An unplugged temp sender should read zero on the gauge.


hemi3TC