Another stupid fuel gauge question

[cghstrojan08]

Ok. I have aleast six months ago put in a 67 F-600 instrument cluster. Now all of the sudden the damn thing is acting up. As I come to a stop, the fuel gauge goes to past empty like the power is going away. I hit the panel a little bit and it comes back. Then of course it keeps doing it. So then when I get how I get so pissed off that it isn't working I punch the dash and then it comes back. Of course then in the process of punching I crack my already cracked dash from a previous punch more.

Ok, I believe it sounds like a grounding issue doesn't it?

Also, about a year ago I replaced the sending unit. If that helps for some reason?

[Banjo]

does sound like floating ground issue.

[fordman]

yea loose wires or a bad ground. maybe the guage has the problem internally.

[cghstrojan08]

Ok, if I ever get the push to look at the gauges again maybe I will do so.

[seattle67]

There should be two connections on the back of your fuel gauge, check to make sure they are clean and tight. While your at it, check the connections at the sender, that ground connection has a bad habit of getting loose. Most intermittent electrical problems can be traced to a dirty or loose connection.

Let us know what you find.

[l1k2gadd]

Did you find your problem?

Was the replacement fuel sender a new one or a used one that worked like mine?

Remember, your gauges have a HOT feeding them and respond to a varying form of a ground to make the needles come up or go down. This is all of the gauges except for the alternator charging gauge.

Every now and then my salvage yard replacement fuel sender does the same thing. If I take a turn faster than normal when the tank is around 1/4 of a tank or so and the fuel is forced to the passenger side of the truck the gauge drops to empty. It stays there for quite a while. I can take a corner hard the opposite direction and it will come back up. It doesn't bother me because I got to see how long the float rod is on the sender when I replaced it and figure the rubber cover on the float might be catching on something in the tank when I do this.

You banging on the instrument panel might be coincidental and the guage may just be recovering on it's own as it sees a ground from the fuel sender coming back up.

Did you also give a slight squeeze on the two connectors at your fuel sender when you replaced them to be sure they fit tight? Like fordman and seattle67 said, dirty, slightly corroded or oxidized connectors could give you some strange problems.

[cghstrojan08]

Ya, the sending unit is a brand new one from JC Whitney for $18 I think. It works fine now. I haven't done anything and I have drove it some since them. It seems like since my last big punch to the dash before I put it away, it fixed it.

[seattle67]

Thats what we electricians refer to as "FM"

I wont say it here, but I'm sure most of you can figure out what it stands for.

[Thunderfoot]

Thats what we electricians refer to as "FM"

I wont say it here, but I'm sure most of you can figure out what it stands for.

I like "PFM" myself

[basketcase0302]

Hey ya'll,

When A/C guys are in this position, we reach for a...

Big
Freaking
Hammer

Glad you got it fixed Robert, intermittent stuff like that will drive me crazy!

Basketcase

[Underdog97]

A bad constant voltage regulator can cause this to happen. It's the little thing that screws on the back of instrument cluster that looks like a little box.