The Stovebolt Site Forums The Shop Area The Electrical Bay Fuel Guage

I have received a new fuel sending unit. I have connected it, with a ground from the sending unit.

I have converted to 12V, and have a 12-6V resistor in line. I have the sending unit hooked to the E side of the fuel gauge, via the resistor.

As I raise the sending unit up and down, the gauge seems to work backwards. With the sending unit float moved up, the gauge needle moves more towards empty. When it moves down (empty) the needle moves towards full. The strange part is that the range of motion of the gauge needle just goes from below E to just above E, and never gets more.

So, have I hooked up something wrong? Bad gauge?

Thanks,
Steven

the sender will attach to the F post

power to the E post

...pic...


if your new gauge is 12 volts then you don't need the resistor
check the back of the gauge for markings
if your new gauge is 6v the place the resistor on the power side, not the sender.

DADS50,

Thanks....silly me.

Ok,I rewired the gauge correctly, but the needle will only move about a 1/4 inch hovering around the E on the gauge. At least it's moving.

I have:
1. Ensured that I have a well charged battery.
2. Removed the face of the gauge, still the same.
3. Removed the gauge itself, and connected directly to the battery: still the same indications.

I don't see anything burned in the back (provided that one of the windings should be black.

Here are some pics , but don't know if you can tell anything or not.

I'm trying to figure out if I should buy a new gauge, or if this is a problem of adjustment.

Thanks,
Steve

I'm having a similar problem Steve,do you mind if I tag along on your thread?

It's one of those annoying little problems that can spoil your drive.
Whether it's $20 or $80 of gas the needle never rises above the 1/4 mark on mine.
Strangely though when I corner the needle does rise due to fuel surge,so I know it's not binding or hitting the inside of the tank.

[quote=jockbolter50
I'm having a similar problem Steve,do you mind if I tag along on your thread?

It's one of those annoying little problems that can spoil your drive.
Whether it's $20 or $80 of gas the needle never rises above the 1/4 mark on mine.
Strangely though when I corner the needle does rise due to fuel surge,so I know it's not binding or hitting the inside of the tank. [/quote]

Not a problem. The more the merrier. I had a buy botch the POR-15 tank liner application, and now it's either buy a new tank, or probably cut, sandblast, re-weld, and buy another POR-15 kit.....Before doing that I want to see if I'll need a new gauge too....shipping is getting expensive to Italy.

If you connected power to the sender lead on the rear of the gauge, you might have damaged the gauge.


DADS50 has posted a video and info regarding one of the standard/common tests for a gauge. (maybe he will post a link AND maybe he or others will correct/clarify the instructions below)


This is a "bench test" of sender and gauge - the sender is not in the tank and the gauge could be in or out of the gauge-assembly housing:

Put the 12v-6v resistor on the "E" post of the gauge (if you have a 6v gauge).
This is a one-way resistor (it has an 12v-in side and a 6v-out side).

Connect the 12v power lead to the 12v-in of the resistor on the gauge.
Or, if you have a 12v gauge and no resistor, attach the 12v power lead to the "E" post on gauge.

Ground the gauge-assembly housing.

Attach the sender to "F" post on the gauge.
- the gauge should read Full.

Ground the sender at an attachment hole on the sender unit.

Move the sender's fuel-level bar/bulb up and down.
- the gauge should give a reading between F and E, as you move the bar/bulb up (F) and down (E).

Here is a list of diagnostics:
http://www.fifthaveinternetgarage.com/tech_tips_gas_gauge.php

Two things I see in the pictures:
1-Why is the needle on the gauge pointing off to one side?
With no power applied, it should be resting just to the
right of the lower leg of the 'E'.
2- That blue coil. Unless they've used a varnish with a
coloring in it, which I haven't seen before, looks like it's
been over heated, which I have seen before. Assuming that is
a 6v meter movement, was it connected to 12v at some point in
the process??? If so, then it's possible that it's shorted
somewhere in the coil.
dg

"I have the sending unit hooked to the E side of the fuel gauge, via the resistor."

Sending unit was attached to the E side of the gauge.
Power was attached to the F side of the gauge.

Power should be attached to the E side of the gauge.
Sender should be attached to F side of the gauge.

"If you connected power to the sender lead on the rear of the gauge, you might have damaged the gauge."

How did you ground the gauge for step 2 and 3 ?

DADS50,

I attached a ground to the sender side of the gauge, but got nothing, and then tried to the sender itself, and still nothing.

Yes, I initially misunderstood the instructions, and attached the power to the F side. Could be the problem.

As concerns a previous comment about the needle. I too noticed that the needle just seems to 'flop' around. Didn't seem right, but then again, this is my first. So, I don't have anything to compare it to.

Steve

when you removed the gauge and connected it to the battery, did you also ground it?
to test removed, you need power connected, the sender connected and you need the gauge itself grounded.

it wont work without those three

Then there is the concept of a native 12 volt gauge and sending unit. If you told your gauge rebuilder it is for a 12v system, they make the gauge 12v so there is no conversion. I have two sets that were done this way. 6 volts are not even a thought in that case. I like that because there is no resistor, no muss, no fuss.

There are two thought processes. One 'is comprised of' the thought that 'we need to get that 6 volt system to work with 12 volts'

The other is, its a 12 volt system. How about we just hook it up and expect it to work. I have been there, done that so many times. With 6 volt systems involved, things get complicated. If you understand advanced electronics, resistor conversions work, but are not optimal. Optimal enough for our old trucks for sure, but they make entire gauge sets for our trucks that are NATIVE 12 volts. Thats what I am doing without a doubt.

Ok. I'm getting the idea that I just need to order a new gauge.

The other or third thought process is simply to leave the dang
thing alone and run with the original 6v electrical system that
the truck was designed to run with in the first place. And
leave the NATIVE's to their own devices. That's what I'm
doing,,, without a doubt.

Denny Graham
6v fever in Sandwich, IL

Thanks guys. I took the coward way out as I don't have the time. Bought new stuff.

I'll be more careful this time.