All Gauges Reading Too High?

[billdozer]

So, my Blazer has a weird issue that I'm hoping someone can help me solve. I tried searching but didn't find any relevant threads.

Truck is a '79 Blazer I picked up a couple months ago. The gauges (except amp meter) peg too far to the right/clockwise. Of course, I wondered if it was the senders or some other unrelated thing, but I changed the temp sender and the previous owner changed the gas gauge sender in the tank before I bought it and neither had an effect.

The temp runs past the center of the gauge but engine is operating at normal temp. Gas gauge shows way past full when tank is full and is actually empty around the halfway mark. Oil pressure shows way more pressure than usual, probably 75lbs.

So this got me thinking this stuff could be related? Is there a single resistor or some other device that everything runs through that could cause this or should I treat each gauge like as an individual issue?

The truck is very original and doesn't have any added on electrical stuff, janky wiring, etc.

Any ideas? Thanks in advance!

[mongocanfly]

check your grounds

[billdozer]

Originally Posted by mongocanfly

check your grounds

Sounds like a good place to start. They don't flicker when driving rough roads like a loose ground, just FYI but I'll still check.

[Bandit130]

One thing I found that might help. Remove gauges, burnish gauge screws, clips, clean after. This helped mine show better readings. I used sandpaper then cleaned with alcohol. May or may not be your situation, but cannot hurt.

[mongocanfly]

on your fuel gauge issue..make sure he put the correct sender in it...if it shows past full its usually the power to the gauge....

[Dead Parrot]

39 year old gauges and senders might just be shot or connections corroded. 2nd Bandit130's suggestions on cleaning the contacts.

Don't forget the ground from the frame to the gas tank sender. Open circuit on fuel leads to a 3 o'clock reading. Since yours is reading high but still following the fuel level, suspect corrosion in one or more places.

Possible a PO replaced the oil gauge and didn't switch to a matching sender. Or vice-versa.

Temp reading a bit past center is pretty close to correct. Especially if it has a 195 thermostat.