fuel gauge runs backwards.

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miltos68wgoneer
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Location: franklin, CA

fuel gauge runs backwards.

Post by miltos68wgoneer »

I have a 68 wagoneer with a mid 80's poly tank. The sender is new and stated ohms is 73 emp and 10 full. Is this not the same range as the gauge in a 68?
68 WAGONEER / 5.3l, DIY ported heads, long tube headers, lingenfelter cam, griffin rad, trans cooler, E fan /4l70e, front discs,2003 grand cherokee seats front and rear, super wagoneer center console,hydroboost.
53 CHEVY 210 stock

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Stuka
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Re: fuel gauge runs backwards.

Post by Stuka »

In 1980 the fuel senders changed to use the opposite resistance of older tanks. This was a standardization done by the industry as a whole.

You may be able to find a sender that works in that tank with the older setup. Or maybe modify the gauge.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

Topic author
miltos68wgoneer
Posts: 182
Joined: Sat Apr 05, 2014 8:31 pm
Location: franklin, CA

Re: fuel gauge runs backwards.

Post by miltos68wgoneer »

so is the range the same just opposite?
68 WAGONEER / 5.3l, DIY ported heads, long tube headers, lingenfelter cam, griffin rad, trans cooler, E fan /4l70e, front discs,2003 grand cherokee seats front and rear, super wagoneer center console,hydroboost.
53 CHEVY 210 stock

http://s64.photobucket.com/user/miltos6 ... t=3&page=1
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babywag
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Re: fuel gauge runs backwards.

Post by babywag »

You have the wrong sender, there are 2 different 80's senders.
You want the early one, not the late one.

The resistance/sender change didn't occur until 1986 when they changed the dash(fuel gauge).
-Tony
'88 GW (aka Babywag)

Topic author
miltos68wgoneer
Posts: 182
Joined: Sat Apr 05, 2014 8:31 pm
Location: franklin, CA

Re: fuel gauge runs backwards.

Post by miltos68wgoneer »

68 WAGONEER / 5.3l, DIY ported heads, long tube headers, lingenfelter cam, griffin rad, trans cooler, E fan /4l70e, front discs,2003 grand cherokee seats front and rear, super wagoneer center console,hydroboost.
53 CHEVY 210 stock

http://s64.photobucket.com/user/miltos6 ... t=3&page=1
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babywag
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Re: fuel gauge runs backwards.

Post by babywag »

That *should* be the correct one, for an early gauge. Did you check the sender before installing it?

The late model '86-up sender the resistance is opposite.
Low resistance = empty, high resistance = full

Early sender/gauge, if you ground sender wire = gauge pegs full
Late sender/gauge, if you ground sender wire = gauge pegs empty

Early setup, if wire is open, gauge will read empty
Late setup, if wire is open, gauge will read full
-Tony
'88 GW (aka Babywag)
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kansasboy001
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Re: fuel gauge runs backwards.

Post by kansasboy001 »

Simple fix. Just go into the access hole and cut and splice the wires opposite. So hot to ground and ground to hot.
1983 Cherokee Laredo. 360/ 727/ np228/ Junkyard 7427 TBI/ Msd ignition
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babywag
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Re: fuel gauge runs backwards.

Post by babywag »

kansasboy001 wrote:Simple fix. Just go into the access hole and cut and splice the wires opposite. So hot to ground and ground to hot.
No access hole on '68, and you can't reverse resistance values that way. Switching polarity has no effect on the resistance values.
-Tony
'88 GW (aka Babywag)

Topic author
miltos68wgoneer
Posts: 182
Joined: Sat Apr 05, 2014 8:31 pm
Location: franklin, CA

Re: fuel gauge runs backwards.

Post by miltos68wgoneer »

thanks guys. apparently my full tank came back empty from the painters so perfect time to drop the tank and measure the resistance on the sender. When things dry out a little. don't like wallowing in the mud.
68 WAGONEER / 5.3l, DIY ported heads, long tube headers, lingenfelter cam, griffin rad, trans cooler, E fan /4l70e, front discs,2003 grand cherokee seats front and rear, super wagoneer center console,hydroboost.
53 CHEVY 210 stock

http://s64.photobucket.com/user/miltos6 ... t=3&page=1

candymancan
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Re: fuel gauge runs backwards.

Post by candymancan »

aparently.. you mean they took it for a joy ride ? and drove 200 miles ? or they siphoned the gas.. ?
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
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