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valleyguy
09-06-2011, 12:58 PM
1952 2R6 truck: gas guage not working. The truck was converted to 12 volts sometime in the past, so I'm not sure if the wiring has been modified or if it is original.. I have a voltage reducer (diode) to install in the power line (which I am told is necessary) once I figure what I currently have;

My tank sending unit only one connector and one wire leading to the dash guage (it also appears to have a grounding tab, not hooked up), whereas the shop manual for my truck shows two leads on the sending unit; the back of the dash guage shows two connections while the illustration in the manual shows three. In addition, with the way the dash guage is currently wired, the hot lead remain hot even with the ignition key off.

Does anyone know what I have here, and how to fix it?
Thanks,

Joe D.

11018 11019

41 Frank
09-06-2011, 01:08 PM
Some early 2R trucks used a 2 wire connection at the sender and a 3 wire connection at the gauge, hence the illustration in the shop manual. Hot lead on gauge should to be wired to acc. side of ignition switch. Hook up a wire from unused tab on sender to a good ground and see if gauge will work.

valleyguy
09-13-2011, 10:36 AM
Well I did as you suggested Frank (grounded the sender, and switched the hot lead to the accessory terminal on the iginition switch -( at least I "think" its on the accessory lead, its hard to tell from looking at the switch and the manual doesn't say much about the switch). Anway, the guage now works, sorta of... That is, it works when I turn the key on but drops back to empty once the motor is running. My test light confirmed that the hot lead going to the guage (lower connection in the photo) shows power and the greenish wire (puper connection) leading to the sender also shows power when the switch in on; but then it (the sender lead) shows no power when the motor is running. Any ideas?

Thanks,

Joe Diggle

41 Frank
09-13-2011, 11:05 AM
Joe, do you know where the second wire hooked to the lower terminal of gauge originates? In order to check tank sender remove lead from it at the tank and temporarily ground it, turn key on, if gauge goes to full it pretty much proves tank sender is at fault.
If gauge does not move there is a problem in the wiring or the dash gauge. On one of my own vehicles the gauge would move very little when I turned the key on and it turned out to be the cork float of the sender had disintegrated and fallen to the bottom of the tank.

valleyguy
09-13-2011, 12:31 PM
Frank I tested the sender as you described and it seems to be ok, thus I assume some problem with wiring, or switch. When I got the truck, the hot lead was connected to the terminal on the right side of the ignition switch, which is always hot, so I knew that was wrong. It is now connected to the lower left terminal, (the yellow wire with the blue tape on it); I picked that one simply because it was only hot with the ignition switch "on". As you can see, there are a lot of wires on that ignition switch, most of which I haven't yet been abloe to trace.

Joe D.

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nvonada
09-14-2011, 07:59 AM
That is some unfortunate wiring. Wire nuts should never be used on auto wiring. I am not a big fan of the blue quick-splice connector used to join two wires either. Looks like a lot of fun to trace!

valleyguy
09-14-2011, 09:18 AM
You got that right; its a mess. But regarding my gas guage hookup, I would like to be able to identify each connection on the ignition switch; As I said, the manual is no help. ??

Joe D.

41 Frank
09-14-2011, 10:41 AM
It would be a good idea to trace all the wires and hook them up correctly. All terminals should be marked on the switch Like " batt" "ign" "acc." "start" I suspect where you have the fuel gauge wire connected now is actually the "ign" terminal, as there appears to be nothing else hooked to it, it should have the wire to the coil hooked to it. I believe it is probably hooked to the acc. side. While it will work this way it is not correct.

Frank I tested the sender as you described and it seems to be ok, thus I assume some problem with wiring, or switch. When I got the truck, the hot lead was connected to the terminal on the right side of the ignition switch, which is always hot, so I knew that was wrong. It is now connected to the lower left terminal, (the yellow wire with the blue tape on it); I picked that one simply because it was only hot with the ignition switch "on". As you can see, there are a lot of wires on that ignition switch, most of which I haven't yet been abloe to trace.

Joe D.

11187 11188

valleyguy
09-14-2011, 04:59 PM
Guess I'll pull the ignition switch and try to figure out whats what. What has me stumped is the fact that the sending unit wire is hot when the ignition key is turned on but goes cold after the motor is started... BTW that second wiring going to the gas guage is the hot lead for the electric wipers which the po or someone before him had installed. Don't know why he picked that particular spot to hook it to..So, as far as I can tell, things added to the harness include: electric wipers, electric fuel pump, signal lights. I'm tempted to just get a new wiring harness and start over...but thats probably more a winter project.

Joe D.

41 Frank
09-14-2011, 05:06 PM
Joe, at least you are blessed with excellent accessability to the dash wiring, unlike the cars!

Guess I'll pull the ignition switch and try to figure out whats what. What has me stumped is the fact that the sending unit wire is hot when the ignition key is turned on but goes cold after the motor is started... BTW that second wiring going to the gas guage is the hot lead for the electric wipers which the po or someone before him had installed. Don't know why he picked that particular spot to hook it to..So, as far as I can tell, things added to the harness include: electric wipers, electric fuel pump, signal lights. I'm tempted to just get a new wiring harness and start over...but thats probably more a winter project.

Joe D.