Temp needle bouncing around?!

[jakez]

Info: s13 redtop sr20det

So I pulled into my driveway and glanced at my temp and it's pegged way past overheating. Scared the shit out of me so I quickly leave my house and start cruising around low rpm trying to cool it off and then the needle starts having a mind of it's own just randomly bouncing around. It would show overheating and then sweep back to where it usually sits between H and C and then sweep back to overheating again and shake the needle, and then go back and forth over and over for a second. It was just doing all kinds of random shit no pattern or anything, but the majority of the time it would either sit on crazy overheating or perfectly normal where it usually sits. I've never had an overheating problem so I'm figuring everything is fine and one of my sensors just fucked up?

Other info: I had a bung welded onto my test pipe today but didn't have time to install the wideband, so I drove around with like a 1/2 inch hole in the middle of my exhaust. Is that really bad to do? Other than that I don't understand why this is happening all of a sudden.

[Pacman]

Look at the single wire temperature sensor (next to the engine coolant temperature sensor). That temperature sensor has a tab that looks like its cold riveted. My engine was showing similar readings (pegging cold instead of hot like yours) and the peg was loose on the sensor causing to make false readings due to a loose connection.

If you've done any coolant work, make sure there's no bubble in the system. Make sure you don't have a cold spot in your radiator (indicating a plug at that location). Once hot, turn engine off and carefully touch the radiator through the fan felling any abnormal cold spot. Those are some of the more common issues with cars. Its most likely the connection issue at the gauge sensor.

[RyanS13]

Look at the single wire temperature sensor (next to the engine coolant temperature sensor). That temperature sensor has a tab that looks like its cold riveted. My engine was showing similar readings (pegging cold instead of hot like yours) and the peg was loose on the sensor causing to make false readings due to a loose connection.


This^^^^^^^
My temp. gauge used to do this alllllllll the time, except like Pacman, mine would go down not up. So check that out first before anything.

[MrsFieldsKOUKI]

I'm actually having the same problem, mine too goes down occasionally especially on acceleration. If not the temp sensor could it be loose screws on the cluster?

[rat240]

have you recently removed your cluster

the same thing happed to me with my gas and temp and it was cause by the harness not making contact with the pins on the cluster board

[jakez]

Well it hasn't done it again since so...

And no, haven't removed my cluster or anything.