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Discussion Starter · #1 ·
Has anyone used the Autometer Sport-Comp 3315 fuel level gauge? Will it work good in my 65 stang? I'm looking for a good fuel level gauge that reads correctly without bouncing back and forth when the gas sloshes in the tank. I have an older model Autometer now, but the needle bounces back and forth all the time. Will this happen with the 3315 gauge?
 

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I have no experience with either of those guages, but my guess is the sending unit has more to do with needle movement than the guage. Think of it like an oil pressure guage. The guage just reads what the sending unit is sending.
 

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I'm guessing if the needle is bouncing back and forth, you have a bad ground, or a bad sending unit(I'd check the ground first).
 

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Discussion Starter · #4 ·
It is a new sending unit that I put in when I installed the new gas tank a couple years ago. The stock fuel gauge doesn't bounce around, but this aftermarket one I have does. It only bounces around when the gas sloshes in the tank. I think there is some resistance built into the stock gauge so that it does not move as fast as the sending unit does. I've measured the ohms of the sending unit and it is correct. I'm just wanting a gauge that will read correctly. Any suggestions?
 

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Sounds like the guage is just too accurate. I'd call Autometer tech and ask if you can retard the guage with some type of resistor.
 

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Discussion Starter · #6 ·
I'm going to be doing some testing on my sending unit to make sure it is reading correctly. Is the sending unit read out linear? If when full, it reads 10 ohms and when empty it read 73, then when it is half full should it read around 31-32 ohms? I checked my fuel gauge at lunch and it is the Autometer 2515. I've noticed that it does not read right either. When it shows I'm almost empty, I really have about half a tank. Do you think the sending unit could be that far off? It is an aftermarket sending unit and is about 3 years old.
 

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The gauge should be accurate if you purchased one with the correct Ohm range. The 3315 does.

The slosh thing is a different issue altogether. Your stock gauge was designed to run on pulsed 5V power. The Auto Meter gauge runs on constant 12V. Every Auto Meter fuel gauge I have ever used has shown the slosh like that. I have been planning for a while to build a pulsed 12V regulator and see if that smooths it out or not.
 

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Discussion Starter · #8 ·
Yeah, the 2515 gauge is a 73/10 ohms empty/full gauge. My sending unit may be bad. I'll have to take it out and do some testing with it tonight. I can live with the slosh, but I want it to read more accurate than it currently is.
 

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Discussion Starter · #9 ·
I think I have found why my fuel gauge reading was off. I checked my sending unit last night and at empty it was reading 90 ohms and not 73 ohms. This explains why my gauge would show empty when I still had between a 1/4 and 1/2 tan left. After I took the sending unit out I notice that I could adjust it by unscrewing the float and turning resistor that the float was screwed to. I was able to make it read around 73-74 ohms at empty. I haven't try it out yet, but I'm thinking my gauge should read more accurate now.
 
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