Bouncing Temp Gauge - anyone?

[forte500]

My temp gauge (not oil level) "bounces" when I accelerate or rev the engine....at idle it reads fine....anyone deal with this before?

[JFairman]

No, but I have on BMW's and it was a poor ground connection on the gauge in the plastic instrument cluster. Porsche 911 gauges are all metal but are mounted in a rubber grommet insulating them from the chassis so they have to have a ground wire on them.

Could also be bad connection on the single wire on the oil temp sending unit, or the sending unit is toast. That's the little one next to the larger oil pressure gauge sending unit located at the back end of the main bearing oil galley a little below and to the right of the engine fan housing.

[forte500]

Your talking about the sending unit to the right (looking down at the engine) of the oil breather housing....where is the "larger one"?

[JFairman]

You're thinking of the oil pressure idiot light sending unit next to the breather cover way in back when looking at the motor.

I said a little below and to the right of the engine fan housing. Thats the big round metal fan right in front when you open the rear lid.
The larger than average VDO oil pressure gauge sending unit and oil temperature gauge sending units are both located down there next to where the right side cam tower oil line comes out of the case.

[forte500]

lol...I feel like an Idiot. Wire was just about off on the sending unit...I must have tugged on it inadvertently when messing with the fan housing and compressor mount. Thanks for making me look in the right place!!! Appreciate the quick response.