Need some gauge help...

I bought some gauges for my '56 Ford pick up. They are modern gauges made with original style faces that go into the stock cluster. The problem I'm having is that the temp gauge and the volt gauge read too high when the truck is running. At room temp, the temp gauge is about ¼ of the way up, and when the motor is up to temp its up to the "H". The motor never breaks 180, so I know its not that hot. The volt gauge seems fine with the key in the on position, but when the alt. starts charging, the gauge swings way over to the + side. Ron Francis says its the gauges, the gauge people say its the wiring. ??? I'm thinking the sender for the temp is the wrong ohm range, but they swear all there gauges use 1 type of sender. The volt gauge, I don't know...it just seems like its to sensitive(if thats possible). Any help or guidance would be appreciated. Thanks, Matt

 

Add resistance to the line.

Get a variable resistor from Radio Shack (as low an ohm range as they have) and put it inline with the sender and play with it until you are happy with the range readings.

Figure out what that reading is, and solider in a resistor of the same ohms. (Or leave the variable one in place and lock it down.)

 

check all your grounds..gauges do funny things with poor grounds. i once had a car that the temp gauge would jump 15 degrees when you turned on the headlights


did you use sealer on the threads before installing them?

 

The gauge people had me run new grounds, and that didn't effect it at all. I didn't use any sealer on the temp sender. Keep the suggestions coming. The gauge people said they'd send me some new gauges to try, but I don't have a lot of faith that that will fix the problem.

 

Temp, fuel and pressure gauges rely on a difference in resistance (you prolly knew that). The differences are small, so the wiring has to be top notch or the gauge will read funny.

Swop gauges from car to car (identical cars) and chances are good they will read different. Senders can be off tolerence just a little and that will affect the reading.

You said you did not use sealer on the sender, and that's good. But is the block grounded to the battery?? I like to use two grounds from the battery - a 0 or 00 to the block, and 4 or 6 gauge to the body, and the same from body to frame (if applicable).
I'd ground the metallic paint on a 'Vette if I thought it would help....

Are the senders the right ones for the vehicle?? Have you tested the senders out of the vehicle (candy thermometer in a pot of water, sender/gauge wired for testing in same water)??

The resistor dodge is actually not a dodge, but a real, viable solution. Years ago, Kawasaki had a rash of complaints from the 900 Ninja running hot. The engine was running the correct temp, but instead of trying to educate the monkeys riding them, they just put a resistor inline to the gauge. Instant happy monkeys!!

You could also try a different sender.

Cosmo

 

The block is grounded twice. The gauges and senders are aftermarket, and they assure me they are correct(?). Never tried testing the sender. Still waiting on a call back from the gauge people to see if they have any other ideas.