Temp Gauge Calibration


mb571
10-10-2010, 04:25 PM
88 Camry, 2000cc 16 valve 4cyl.

After many years of cussing at my intermittent Water Temp gauge, I finaly got serious about it and fixed it. I had once replaced the sending unit but that didn't help. It would go to full scale intermittently. I could hammer the dash and sometimes get it to go back. I took apart the speedo head and took the gauge out and then soldered some cold solder joints on the meter circuit board.

My problem and queary now: how to place the needle in the right positon.
Try one I grounded the sender wire and placed the pointer needle on the meter shaft at full scale. This wasn't quite accurate.
Try two I pulled the needle off and place it mid-scale when I guessed the engine was at operating temp. The compounding factor to the problem is that the car has cooling issues too.

The question: does anyone know what the needle should point to at a given resistance value from the sender?
Does anyone know at what temp the needle should go into the red of the gauge to show over temp?

Thanks,
Mark

jdmccright
10-11-2010, 03:11 PM
Try to download the body electrical service manual for your generation at the top of this forum. There are diagnostics that can be done to help you get it it right.

Brian R.
10-11-2010, 10:32 PM
Altenatively, you can replace the meter with one from a salvage yard.

mb571
10-11-2010, 10:40 PM
The meter works. I just need to put the needle on the right spot of the shaft.
Can anyone tell me at what temp the needle should reach the red "H" on that engine? What is normal operating temp?

Mark

Brian R.
10-12-2010, 04:22 PM
If my memory serves me correctly, the thermostat in that engine is 180 deg. That would make it half-scale. Can't you just run the engine with the temp gauge out, but connected and place the needle half-scale at that time?

Just talking, but you may spend more time (money) on fixing this gauge than you would by buying one from a salvage yard.

mb571
10-12-2010, 07:42 PM
If you were buying one from the salvage yard, it would be the whole speedo head complete with incorrect odometer reading. If you were to take the temp gauge alone, once again you'd have to remove the needle to uninstall and install.
With the correct info, it is a 2 minute fix!

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