Temperature gauge weirdness

[Newfie_dan]

those specs are for the 2 wire coolant temp sensor, the single wire one is for the gauge only it has absolutely no bearing or affect on the vehicle's running or ecm. The single wire coolant temp sensor is for the dash board gauge only. To check and see if its the gauge at fault just unplug the single wire sensor, the gauge is basically just an ohmmeter, if the resistance is very low then it will cause the gauge to spike or drop depending on how it works, you should read some resistance from the top terminal on that sensor to the chassis or negative terminal of the battery with the wire disconnected and the vehicle off and it should also change from when the engine is cold to when it is hot. Also using clr to remove electrical corrosion won't really be effective, use rubbing alcohol on it first from a spray bottle, allow it to sit for a few mins then clean it off with an old toothbrush and some more rubbing alcohol. If its really packed in there use a stiffer small wire brush to clean it off. As an added note electrical corrosion works great as an insulator and it will up the resistance on a circuit very well, I would be inspecting the wire lead to that sensor as well to see if that corrsion made its way up the wiring.

[jeff180]

ok that's the one i'm trying to diagnose. (temp gauge sender). i have been told that the guage from the 4cyl is different from the 6cyl. i did some cross referencing and found the sensor/sending unit is the same for both the 1.6 and the 1.8. i took this guage from a 6cyl m/t (just the temp/fuel guage) and put it my 4cyl a/t.

[Newfie_dan]

the gauge may possibly be at fault but if I were you I would do a check with a mulitmeter on the sensor itself when its warm and when its cold and see what the difference is as well as a resistance test from the signal wire from your gauge to the end that connects to the sensor and see if it shows any resistance, it should not show hardly anything on that wire from end to end maybe an ohm or 2 tops.