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Discussion Starter #1
Last weekend I wanted to troubleshoot the bad gas gauge in my 57 so I tried to pull the wires off the back to test things out. Either I'm pathetically weak or I'm doing something wrong because they just WILL NOT COME OFF! I can twist them, but they won't disconnect. Check me please. They just pull off, right?

Thanks
Ed
 

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The wire going to the sender is held on by a small nut and washer on mine.

Fuzz

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Discussion Starter #4
Pretty sure they are pushed onto the stubs on the rear od the gauges.
That's my understanding as well, but these sure don't want to come off! I'm wondering if maybe a flat blade screwdriver to use as a pry tool might help.

The wire going to the sender is held on by a small nut and washer on mine.
Fuzz, is your car a 57 as well? I don't see any nuts on mine.

Ed
 

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They get stuck with age (a bit like me lol). Use a pair of plyers and GENTLY rotate the lugs on the pins. Once they are free'd up they should pull off ok, perhaps with the use of plyers/screwdriver.
 

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Restoman1,

Sorry. I misread your post. I was referring to gas sending unit and after Re-reading your post, you are talking about dash gages. My error.

Fuzz

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The plugs seem to grip onto the posts if they are tightened before pressing on, they should just unplug.
 

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Discussion Starter #8
Part of the problem is that I can no longer get my hands up there. When I first tried a few months ago, I had the radio, heater control and the glove box out to work on installing a new radio speaker. I tried at that time, with no success, to get the wires off the back of the gauge. I finally gave up and put the dash back together again. I'm going to have to pull all that stuff back out again to take another shot at it.

However, before I do that, I'm going to verify the under dash connector going to the rear harness is tight, and if that's not the problem, I'll disconnect the wire at the sender and ground it to the frame. If the gauge goes to empty, I'll know that the gauge itself is working. When I replaced the sender a year ago, there was a wire going from one of the screws on the sender to the body. I removed that, but I don't remember if the gauge still worked after I did that or not. I'll probably ground the sender to the frame just to make sure.

If none of this helps, I'll HAVE to mess with the wires on the gauge.

Ed
 

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Sorry restoman...Nothing to do with what you are dealing with...But, I feel I have lost a bunch of strength over the years as well....Had to load a a new cartridge in my grease gun the other day....It was quite a fight...Wasn't sure who was going to win.
 

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Discussion Starter #11
Well, I'm stumped!

The gauge always reads empty with the car off (normal), but ABOVE full with the car running (not normal, especially since I only have a half tank of gas in there), so here's what I've done:

(Luckily, there's a 1/4" slot between the gauge housing and the dash (see attached), so I was able to get some jumper clips in there and attach to the pins on the gauge.)

1. I checked the connector going to the rear harness (even pushed on it to make sure it was tight) and it was.
2. I verified with my VOM that the gauge had 12 volts going to it.
3. I grounded out the POST on the back of the gauge that has the brown wire on it and the gauge went to (almost) empty. (It actually went to about 1/8 of a tank, but that shows the gauge is okay, right?)
4. Just to make sure the brown sender wire wasn't broken somewhere, I ran a jumper wire outside the car from the sender on the tank to the back of the gauge, but the gauge still went to above full.
5. I ran a jumper from the gas tank to the frame just to make sure the tank had a good ground, but that didn't help. The gauge still goes past full.

I've done all that I can think of, so my only conclusion is that I have a bad gauge, but even that doesn't make sense because it has 12 volts going to it and if I ground out the brown sender wire, the gauge shows (almost) empty. But maybe that's where I'm wrong? Maybe it should go to COMPLETELY empty when grounding out the sender wire?

Thoughts?
Ed
 

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Discussion Starter #13
Pops, I used my old Classic Chevy International "Tech Book" as my guide, but from your web site link:

Gauge pegs itself to the right, above full, some possibilities are:
  1. Brown wire is off back of gauge. (It's not. As a matter of fact, I can't get it off!)
  2. Poor connection at underdash to tail lamp harness plug. (It's not. I pushed against it just in case, but it's really tight)
  3. Brown wire is broken between gauge and sending unit. (It's not. I used a long wire to bypass the brown wire and it did the same thing)
  4. Brown wire is off of the sending unit. (It's not. Screwed on nice and tight)
  5. Bad tank to body ground. (It's not. I grounded one of the screws attaching the sender to the tank to the frame with a jumper just to make sure.)
  6. Sending unit is bad. (It's a 2 month old sender. I replaced it only because the original was missing the "sock")
Ed
 

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Discussion Starter #14
It's acting like the sender is bad, but like I said, it's only a few months old. However, it IS a reproduction, so who knows. I'll see if I can find my original and see what it does.

Ed
 

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Discussion Starter #16
Well son of a b...

It IS the sender! A 2 month old sender that's gone bad! I found my old (original GM) sender and although it has a few dead spots, for the most part the gauge moves when I move the arm up and down. Looks like I'm on the search for another sender. The one put in there a few months ago is a Fargo P/N 55C-9300-3 so anyone have a recommendation for a better one?

Ed
 

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How much fuel is in the tank and how many ohms is your sender reading?

Or did you take it out and get your readings?
 

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Discussion Starter #18
Pops, I didn't remove the sender. I just used my old sender to test the gauge. There's (approx) 1/2 tank so even if the gauge is off, or the sender is off, it should at least read something other than pegged.

Ed
 

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