Need gauge help...

J

jaxV8carz

Member
This is on Shoebox also...
I recently replaced the instument cluster on my '51 Ford. I reused my gauges and reset the odometer to match the existing reading. I took photos of the back side to be sure all was reconnected the same way. The '51 has 2 jumper bars to supply power to fuel, temp, and oil. Then each gauge has a wire that goes to its respective sender. I put the unit back in and switched on ignition and started the engine. All works correctly except the oil indicator goes to max and stays there. This is with the engine running or not. With the ignition switch to OFF, the needle goes back to zero. I even disconnected the wire at the oil pressure sending unit with the engine running and nothing changed. I'm perplexed. What is going on? Any ideas? Thanx!
 
I'd say there is a short in the circuit. First guess would be a bad sending unit going straight to ground. If there's no resistance in the sending unit, there's nothing to "regulate" the gauge. Good luck
 
"disconnected the wire at the oil pressure sending unit with the engine running and nothing changed." Probably not the sending unit then. More likely grounded between gauge and sender, not likely to be good for the gauge. ..B.
 
Just a guess, but recheck how the gauge is mounted in the instrument panel. It may be grounding there.
 
jaxV8carz said:
This is on Shoebox also...
I recently replaced the instument cluster on my '51 Ford. I reused my gauges and reset the odometer to match the existing reading. I took photos of the back side to be sure all was reconnected the same way. The '51 has 2 jumper bars to supply power to fuel, temp, and oil. Then each gauge has a wire that goes to its respective sender. I put the unit back in and switched on ignition and started the engine. All works correctly except the oil indicator goes to max and stays there. This is with the engine running or not. With the ignition switch to OFF, the needle goes back to zero. I even disconnected the wire at the oil pressure sending unit with the engine running and nothing changed. I'm perplexed. What is going on? Any ideas? Thanx!
Click to expand...

I think most of us feel that "nothing changed" means that the oil pressure went to max scale again. If so it is not a problem with the sending unit. I would disconnect the wire at the gauge which goes to the sending unit. If it still maxes out, the problem is somewhere in your gauge/cluster.
Take the gauge out and apply power to it and ground the gauge mounting point. It should not max out. If it does, the gauge is bad (I would guess points are stuck).
 
Here is a diagram for you, check it against your cluster..

wiring.jpg
 
Lots of great info, guys!! Thanx so much. I disconnect the wire to sender and gauge still maxes out. I can play around with the jumper bar connection and it will max out and then it won't. As much as I HATE to, it looks like I may need to pull the cluster. But first I'm going to try to remove the 2 screws that hold the individual gauge in and try to eliminate in direct shorts to ground there. All other gauges are doing the right thing. Jack
The verdict is in.........I went back at it and loosened the 2 nuts that hold the gauge to the mount plate, wiggled it a bit, crossed my toes, did a little prayer, tightened them back up, and it would appear that I eliminated the gauge to ground. Now the needle doesn't move when switched ON, but goes up to a normal reading upon starting. I may be part Irish...maybe it's the luck of the Irish helping out. Thanks to you all. Jack
 
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