Wiring gas gauge & sender

[Track T-4]

I have an Auto Meter gas gauge with the Auto Meter sender installed in a new tank (thanks Ron Pope!) but am unsure of the wiring. The Auto Meter instructions say:
1. Connect a wire from the terminal post on the sender to the gauge.
2. Connect a wire to a ground on fuel tank to the gauge.
3. Connect a wire from ignition switch to positive terminal on back of gauge.

I am ok with #1 and #3 but my question is about #2 - the ground wire.

Before finding these instructions, I ran a wire from one of a bolt on the sender to the chassis as a ground. I also have a ground from a bolt on the filler neck that is on the tank to the chassis and a ground from the base of the filler neck that is on the fiberglass body to the chassis.

Do I need to...

Replace the ground wire attached from the sender base to the chassis with a wire going directly from the sender base to the gauge

or

Leave the sender grounded to the chassis and add a ground wire from the gauge to the chassis

or

Leave the sender grounded to the chassis and add a ground wire from the gauge to any mounting bolt on the tank

or??

The second option would be the easiest for me because of access but I want to insure that is correct.

Signed,
Electrically Challenged

 

[ellis8500]

Leave the sender grounded to the chassis and add a ground wire from the gauge to the chassis

 

[Track T-4]

Bill,

I thought that would work but wanted to get another opinion. Thanks.

Bruce

 

[ellis8500]

All of your electric gauges should have a ground connection. Daisy chain them into the ground circuit or connect them all at one point.

 

[Track T-4]

I wired all new gauges a couple of years ago and wired/grounded all but the fuel gauge. The reason was the original builder never put a sender in the tank. Couldn't check the level with a stick and after running out of gas twice - and other related issues - I bit the bullet. The body and everything attached to it below and on top had to be stripped to get to the tank. Decided to install a new tank with a sender, vent, etc and finally hook up the fuel gauge. I wired the tank as you suggest but what threw me was when I read the instructions and they said to run the ground all the way to the gauge. Almost all back together again, hopefully tomorrow.

 

[TriodeLuvr]

what threw me was when I read the instructions and they said to run the ground all the way to the gauge.

There are lots of reasons why a frame isn't the optimum way to ground things. They're suggesting the way it should be done when possible.

Jack

 

[EX JUNK]

I always use a star washer between the frame and the wire connector. That way the "teeth" of the star washer will bite into the frame and insure a good grounding connection.

Jim

 

[ellis8500]

Grounding to frame must be OK...in commercial and military airplanes there are hundreds of grounds to the frame [fuselage and structure]

 

[Screaming Metal]

When dealing with electrical stuff and grounds, you can never have 2 many grounds. Ground your Gauges, ground your motor, ground your sending unit. Use star washers, use something to keep rust and corrosion at bay. Keep your terminals tight.
Loose terminals, and corrosion cause resistance that can cause bad readings, malfunctions, even fires. Keep you cables away from fuel lines if at all possible. Too big a wire is better than too small a wire. Fuse things, everything electrical should have a fuse or some type of protection.
Electricity is like a water pipe. Your sending unit is like a valve with a handle on it. Avoid chaffing and sharp edges....use grommets, wireties, anchors where needed. Shrinkwrap things when possible....
I always use a separate secondary ground wire for systems throughout a car. Besides a grounded frame. Especially to the ignition and the lighting....

 

[Wild Mango]

The reason why the gauge manufacturer wants you to run an earth (or ground) wire back from the tank to the gauge is because he wants to eliminate resistance in the gauge circuit as much as possible. The sender itself is a resister device, and any extra resistance in the circuit will introduce inaccuracy. Some top end gauges actually measure the loop resistance and subtract it from the sender ohmage reading. Auto Meter is good stuff, so it may well do this.
What Screamin'said......... Learn from the greyhairs, we seen most of it at least once before.

 

[Track T-4]

Makes sense, thanks for the explanation.

 

[iajjpop]

I fought a gauge in the dash , give up ..I bought a gas cap with a gauge built into the top of cap. Like some mowers use. I look at it when I get in the car & check it. Works for me.

 

[Track T-4]

Attended the NSRA Eastern Nationals in York, PA last weekend. Drove around for four days in some beautiful weather and never once worried about if I would run out of gas or not - because the gas gauge now works! Now about that slight death wobble that has managed to work it's way back into the front end...