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Fuel Gauge reads backwards?

Fuel Gauge reads backwards?

Kafka

Jeeper
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Location
Vermont
Vehicle(s)
1979 CJ7: AMC 304 V8, T-18 tranny, Dana 300, Stock front diff, Dana 44 rear with Detroit locker.
I think I have a gremlin in my wiring harness.

In doing my current rebuild of my '79 CJ7 , I replaced all the gauges with Stewart Warner Wings gauges. I have all of them working, except the fuel gauge which is causing me fits. It is a 90-0 ohm gauge, which I know is different than the OEM sending unit so it will never read accurately, However it is reading backwards: Full when empty and empty when full. I have messed with all the wires, re ground everything, and still cannot figure this one out.

Of note, I installed a Painless Wiring universal CJ harness, and am wondering if that is the culprit, as I have found several errors in their wiring diagrams.

Thanks,
jim
 
I have all of them working, except the fuel gauge which is causing me fits. It is a 90-0 ohm gauge,
Jim, double check your gauge, I believe some Stewart Warner Wings fuel gauges are 0-90 ohm which would explain the gauge reading backwards. Jeep sending unit is 73-10
 
Jim, double check your gauge, I believe some Stewart Warner Wings fuel gauges are 0-90 ohm which would explain the gauge reading backwards. Jeep sending unit is 73-10

Yes, SW gauges read backwards...IIRC there may be a SW guage that reads 'forwards' :confused: But VDO does read the proper direction.
 
If it has two wires at the guage have tried switching them? I know that may be to easy ;)
 
If there are 2 wires I would caution against switching them. At this point the sending unit works, switching could possibly send 12v straight to the sending unit and frying it.
 
Thanks. I thought the fuel gauge read the ohms differently. I am going to see if I can retrofit a S-W sending unit, so maybe I can get the correct reading.

Thanks for the help, this one has been bugging me.

jim
 
E = Enough, F = Fill it up?

Sent from my HTC6525LVW using Tapatalk
 

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