I replaced the fuel gauge and it seems to be working but about a 1/4 tank too far to the right. The tank is full but the needle moved past the full mark about 1/4. If I pull the wire at the tank, the needle moves way farther to the right (as it should with no ground at all). Plug in tank wire and it returns to the 1/4 past full mark.

Do you have to pull the needle and and place it back on pointing at the right spot on the dial?

 

mismatched fuel gauge and sender. doubt you can adjust gauge needle

 

there is only one fuel gauge for 77 to 82, how could it be miss matched?

 

There are a couple of ways to 'adjust' it. First, you could bend the float arm to get it to read more accurately at full tank (or at empty, which I think would be more useful). Also, you can adjust it with additional resistors to modify the sender signal going to the gauge.

Unfortunately, there is no "manual" for how to do either. Willcox may have some advice on this one.

 

just looking at it, you can't pull sender with out dropping tank. IDK if I want to go that far. Did I miss something?

 

Much more important to be accurate at "E" than "F"...good luck....

 

Here is my suggestion for how to deal with that issue:

1. Fill tank completely. Take reading on gauge. If reading is above Full mark, measure the distance past that mark and record it.
2. Drive until you get down to the 1/4 mark exactly. This needs to be the reading when you are sitting at the [same] pump ready to get fuel. If the mark is slightly under or over the mark, measure distance and record it.
3. Add fuel until you get the gauge to read 1/2-full. You will need to turn the key to ON occasionally and even run the engine at idle for a bit to get the gauge to "settle in" completely. DO NOT PUT PUMP NOZZLE BACK IN THE PUMP; you want to continue filling the tank after this step. When at 1/2-full, record the number of gallons used to the nearest 1/10 gallon.
4. Add fuel until you get the gauge to read 3/4-full. Use the same process as in Step 3 to do this. Record the number of gallons used to the nearest 1/10 gallon.
5. Add fuel until you get the gauge to read exactly at the Full mark. Use the same process as in Step 3. Record the number of gallons used to the nearest 1/10 gallon.
6. Add fuel to completely fill the tank.

You will now know how many gallons the gauge measures between 1/4 tank-to-1/2 tank-to-3/4 full tank-to Full, and also how many gallons between Full mark and a completely full tank.

7. Drive car until gauge reads at exactly "E"mpty mark (keep an 'eye' on how much fuel you see in the tank so that you won't run out...OR...carry a 2 gallon tank of fuel with you in the case that you run out).
8. Fill tank completely from "E" mark to determine how many gallons used from full tank to "E". You can then subtract that number from the actual capacity of the fuel tank to know how many gallons you have "in reserve" when you hit the "E" mark.

Finally, with all this data, you can then decide whether you actually NEED to recalibrate the gauge...or not.
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P.S. When you get all the data, if you still feel like you need to shift or adjust the gauge readings, post your data on this Forum and I will attempt to provide you with a way to insert simple resistances in the circuit so that the gauge will be more "useable". When that is done, you will need to repeat the fuel tank fill process to obtain new tank-fill data.

 

John.. I've been working with you on the other thread... I'm not sure if you looked... In that thread I've posted how to test the dash unit with an old flasher...

But all the info you need to find your issue is in that help page on our site.

No you should not have to re-set a needle unless you have removed it yourself. I've never seen one come loose.... And I do not think the dash unit is the issue.

Willcox