Rally temp gauge
 

Hey all
Converted to rally a while back. Only gauge not working correctly is the water temp. Has new delco nail head sender. As car warms up it does respond but runs up to pegged hot. Still runny triple gauge until I trust it. But that gauge shows normal running temps.

Ideas ?
Ty.

I'll throw a shot at it.

Disconnect your wire to the sender. Take resistance readings at the sender with a multimeter starting with engine cold, and periodically as it heats. Try to see where the temp vs resistance chart goes off the rails, or if it tracks as it's supposed to.

At 70*, resistance should run between 600-700 ohms. As temp goes up, resistance goes down, where you might have 50 or less ohms resistance at 250*.

Some have used variable resistors to check the proper operation of the gauge.

I saw something on team Chevelle where 68 seems to be an odd year. Maybe your sender is not right for your gauges.

https://www.chevelles.com/threads/co...-unit.1084088/

The modern “new” delco temp senders won’t work with ‘68 gauges as you've discovered. Find a 1513371 “nailhead” or 6402383 “spade” if you can. Or else try one from Lectric Limited, as they claim to have compatible ones. You could also check with Pete Serio as he might have something.

I'm thinking you might have a misprint in your first part number, I think it should be 1513321 maybe?

I checked the temperature-resistance curve of both of my spade and nail head types. At ambient to hot, they track reasonably close. Your sender should have similar characteristics.

Yeppers....thanks!