For the last year I have been having a remarkably frustrating time getting a temp gauge to work properly in my Dart. It ALWAYS reads way too high. Something like 210 when the engine is completely cold, then pegging past 300 as soon as it gets warmed up. I have used 3 different gauges, and at least twice as many sending units, and it's always the same. I have checked and replaced wiring countless times (used a good voltmeter on EVERYTHING, even), but nothing seems to work. I don't get it. This just started last year... Any suggestions?

-josh

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64 Dart 170 /6

Check your voltage limiter. If it supplies the wrong voltage the guage will always read incorrectly. How accurate is the fuel guage? On some (maybe all) of the old chrylsers they used the same limiter for both fuel and temp.

My problem isn't with the stock temp guage (it hasn't worked since I bought the car, all other guages work fine, though) it's with an aftermarket. My current guage is a summit digital temp guage, but I've had the same problem with a few brands. I'm sure this is probably something stupidly simple, like a grounding problem, etc, but it's certainly getting the best of me.

-josh

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64 Dart 170 /6

Are you running all new wiring for the gauge or have you piggybacked onto the factory wiring. I would hook a ohm meter up to the gauge wiring and see what values are getting to the gauge. Where is your sender located? I have a variable resistor lying around that I use to test gauge problems. Mine has values on it so I can turn the dial to whatever reesistance I want. When in doubt about a ground run a 12 gauge wire direct to the battery.

Your using the sending unit that came with the gauge itself, not the stock one, right? If it didn't come with a sender, chances are its calibrated for a GM sender not the stock mopar.

Heh...well...I'll be damned. That's most likely the culprit. I'll check it tonight.

thanks
-josh

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64 Dart 170 /6

Yup yup - unless the gauge specifically mentions for mopar you'd need to use a gm sensor. Also disconnect the factory gauge wire too as you can't run two gauges on one sensor w/o additional electronics (probably just a resistor or two of the right value).

Last I remember, there were no 1/8" gm sensors so a gm sensor can't be easily adapted to our head. You can use brass npt fittings but this will place the sensor that much further back from the head and give you an inaccurate measurment.

One thing you can do, is to drill the thermostat housing for any sensor - but problem with that is you'll only get a temp reading after the thermostat opens, you won't see the engine warming up. Not a huge deal for your situation since all you want is a gauge - but if your feeding an EFI computer thats something you don't want to do.