It won't.
Fuel Guage not working
- Thread starter Andrew Ryan
- Start date
thethee
Senior Member
It won't?
In that case disregard my previous posts.
In that case disregard my previous posts.
darth_linux
Well-Known Member
The video from Dead Dodge Garage is very helpful in understanding how the whole setup works, even if it is slightly different from the C body setup.
Gerald Morris
Senior Member
Look on P 8-93 of the FSM for the fuel gauge hookup:
See it? In the cut out I pasted, its just to the left of the ammeter. The power supply is above it. Look for a blue wire which runs from the gauge to a 6 connector plug, also fed by a black wire off the headlight switch. You CAN test for voltage at this plug, though the dash on a '68 is pretty easy to open and play with.
See it? In the cut out I pasted, its just to the left of the ammeter. The power supply is above it. Look for a blue wire which runs from the gauge to a 6 connector plug, also fed by a black wire off the headlight switch. You CAN test for voltage at this plug, though the dash on a '68 is pretty easy to open and play with.
Andrew Ryan
Member
If the dash on the 68 300 is easy, im glad i have a 68 300! I peeled away layers, got the guage out and i can clearly see the small strand wire fried and broken so no circuit. I see a guage repair place in Arizona but if anyone has a source they like, the referral is greatly appreciated.
Gerald Morris
Senior Member
So, the gauge wire burned up eh? Now, have you TESTED the gauge itself with a 5V source, and an ohmmeter and continuity tester? You should try this before assuming for sure that the gauge itself is defective, and NOT either the crude power supply used by Chrysler, which very well might have burned out. You can use a simple potentiometer, in series with a resistor, say, 20 ohms fixed w a 0-50 ohm pot, on a 5V source, and TEST that gauge. I suspect your "voltage limiter" as MaPar called the power supply, has shorted out, toasting the wire to the gauge, which, upon burning up, may have actually protected it.
Start looking for a 1957-68 fuel gauge if you want it back in the instrument panel, OR, get one from Autometer, and run new wire to the sending unit and a new power supply. I have an Autometer gauge which I used with our '66 Newport, thaat worked perfectly with a new sending unit. It all comes down to what you want to look at and how much you care to spend on it.
Andrew Ryan
Member
Good point but there’s no need to test continuity because i can see the wire from left to right burned and broken. Same way i wouldn’t test a fuse or light bulb when the element is visibly missing. With everything out, I’ll replace the voltage limiter with a solid state one. Minor cost and I’d like to avoid disassembling the instrument cluster again. I’ll start another post about the ammeter which failed years ago and i just bypassed it but having a fully functional dash would be nice.
Gerald Morris
Senior Member
Ah. OK, so it's the internal wire you saw burnt out in the gauge itself. Wasn't sure. You're QUITE RIGHT then. Yes, DO get the solid state "limiter" instead of that crude Victorian thermo-electric crapola Ma Par used in her dash recipe. I think you can score a voltmeter gauge which will work nicely in place of that ammeter. Hell, a little LED strip with IC can be made to light up according to the voltage available from the alternator. OR, if one MUST read current, a SHUNT or toroidal pickup, like an Amprobe can be got to show actual current in the slot originally designated for it.
I enjoy the excellent fortune of having a spare instrument panel for my '68, though to date, the only item I used off it has been the headlight switch. I learned one CAN use early 70s fusie model switches if one cares to swap the rocker off the later sort for the flat bat switch handle on the 67-58 kind. There's a little roll pin holding the chromed plastic handle onto the switch toggle.... While not as proficient as Devon with rebuilding old switches, but I do well enough for my own uses.
Andrew Ryan
Member
Super helpful, thank you. It seems I have multiple problems. The fuel Guage was fried. I sent it to DM Restorations in SC and they repaired it. I re-installed (plus swapped out the voltage limiter for a solid state unit) and the fuel Guage pegs above full, almost instantly. When I unplug the lead to the sending unit at the tank, the Guage reads empty. An inspection of the lead, through the trunk floor and along the rail inside the car is clean, no nicks, not bare wire. I unplugged the harness behind the kick panel, still reads empty so I believe the culprit is the sending unit as I have voltage both at the pig tail behind the kick panel, and at the sending unit. This is the second Spectra sending unit (and the second spectra gas tank, both tanks leaked and I just had the second tank repaired instead of trying to get a replacement from spectra again) so I won’t be buying spectra again. Rock Auto has an alternative sending unit made by Liland Global. Anyone know the brand and is it ok, or should I look elsewhere for a different brand?
Gerald Morris
Senior Member
I've been VERY pleased with what I got from these folks! eClassics.com - Restoration Parts | Auto, Car, Truck, Van, Wagon I bought one earlier on eBay, which now works too, though at first it hung up on something sometimes. I keep it as a spare.
Liland Global is a local (Syracuse, NY) company. It was a radiator shop called Leland radiator ( I used it years ago) This is the story that was recently told to me about the company. It was bought by an Asian guy and he started having radiators copied and made in China with some family connections he had. These radiators were popular with the car dealers because they were cheap... They didn't last much longer than the warranty.
That was some years ago, and it's a story told to me by a radiator shop owner, so I have no real first hand knowledge. I have seen that all their products are made offshore. They also went from doing any retail sales to only working with distributors.
I have read very mixed reviews about their radiators, many of them falling in line with the story I was told.
Their senders might be great, but who knows?? For the money, it might be worth a try.
Gerald Morris
Senior Member
....
IDK who made my senders, though I'm sure they came from China. For the $ they've been good. I would NOT buy a Liland radiator. They look like crap in their pics, as do most others.....
Andrew Ryan
Member
With the new sending unit installed, i get 3/4 full reading with a full tank of gas. Ugh. The old sending unit was grounded (metal strap touching the fuel pick up tube. When i separated them, it reads fine on the bench.
I may futz with it more but again, im getting tired of chasing perfection and im tired and I smell like petrol so I’ll sleep on my next step.
Gerald Morris
Senior Member
Run a grounding bond from the negative post on the battery all the way to your back bumper. Bare wire works fine for this, or insulated. Bond it to the front radiator yoke, the engine block, then the firewall, then the gas tank, the trunki aqnd rear bumper. Everything now will be well connected to the true negative voltage, with minimal resistance. Relying on even NEW sheetmetal to carry current well, given all the paint, oil, dirt, rust and such which accumulates on ferrous surfaces ends in grief such as yours right now, and is common. I have to do this a little better to my own family ride, our '68 soon, but at least the path to the gas tank is good. Run an ohmmeter between your sheetmetal and a wire off the (-) battery terminal if you like and note the resistance. The result may surprise you.
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