78 fuel gauge
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Joined: Jan 2010
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From: Granger Ia.
78 fuel gauge
My fuel gauge stays at 3 o'clock. Went through all the diagnostics from willcox. Everything checks correct. I have 29.9 ohms at the console plug, new printed circuit, gauge resistor checks fine. Could it perhaps be in the gauge itself?
Melting Slicks
Joined: Mar 2009
Posts: 3,126
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Do not buy a guage yet. Did you check the sending unit connection behind the drivers side rear tire? I think the sending unit ohms should be checked at that connection while you move the float arm through its range of movement. If the sending unit is bad or disconnected it will cause the gauge to go to 3 0'clock. I recently repaired my '77 and went through this. What does the gauge go to when you turn off key? mds...
I just went to Willox's site. Did you look at the '77-'82 fuel gauge paper? It states what I posted about sending unit. Loss of sending unit input signal causes gauge to go to 3o'clock. I disconnected the connector at rear tire and checked ohms while moving float arm through it's range with a coat hanger wire. 0 ohms=empty, 45ohms=1/2, 90ohms=full. I would start there. Good luck, post back results. mds...
I just went to Willox's site. Did you look at the '77-'82 fuel gauge paper? It states what I posted about sending unit. Loss of sending unit input signal causes gauge to go to 3o'clock. I disconnected the connector at rear tire and checked ohms while moving float arm through it's range with a coat hanger wire. 0 ohms=empty, 45ohms=1/2, 90ohms=full. I would start there. Good luck, post back results. mds...
Last edited by mds3013; Jan 22, 2010 at 05:04 PM. Reason: more info
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Joined: Jan 2010
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From: Granger Ia.
I didnt know there was one there but I checked the ohms when it was close to empty and it was 8 ohms so I put some gas in it and now have 29 ohms both at the sender and the plug to center console. If there was a braek in the line somewhere I shouldnt get an ohms reading at theplug, right or no?
Melting Slicks
Joined: Mar 2009
Posts: 3,126
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I am not sure if the '78 has the plug like my '77. Ohms readings will change if all wires are hooked up. I found my problem by following Willcox's paper and eliminated sending unit by verifying ohms at connecter behind rear tire with connector disconnected. I do not think I can offer more than the Willcox paper has. Keep at it. Willcox will
probably check in later tonight. mds...
probably check in later tonight. mds...
