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My ongoing speedhut gauge and spectra tank issues

4K views 24 replies 5 participants last post by  thomasshawn 
#1 ·
I posted my previous issues with the spectra tank in the link below.

Prior to swapping over to speedhut gauges I had no significant issues with the fuel gauge beyond the normal inconsistencies. It read full (mostly) when it was full and when it got to ~1/4 of a tank I refilled.

Installed the speedhut programmable and it seemed to work, right away with the 70-10 ohm setting (E-F).

Then I went to fill the tank and it went to E. Pegged at E. Of course I assumed it was the gauge. So I drove around with it like that all day then when I got home I reprogrammed it and it resolved, went to Full. Unfortunately it stayed at full for about 2 days. So I disassembled the dash and check connections. Somewhere in the 15 times I hooked and unhooked the gauge it went to about 3/4 tank and stayed then slowly creeeped up to near F. (I neglected to check ohms at that point) But it was responding so I left it alone.

Worked well for that tank. Seemed to act as expected. Out of habit, I filled up at 1/4 tank and it pegged at E. So, I checked ohms at gauge, and at the tank. Should have read ~15-18ohms since tank was full. Unfortunately both read ~84. I've since driven it more and rechecked and now it's hovering around 80ohms.

So I reprogrammed the gauge to read 90-10 and it's showing slightly above 3/4 tank. Which is probably close but that's not the way this is supposed to work.

In my head I'm thinking that the fuel sender float is bent in some way so that when it's at the most full it has a weird inaccuracy where it slides up the arc of the sender and reads 85ish ohms but as the tank empties it slides back down into normal path and then starts reading in a more linear way like it's supposed to. That might explain why it read correctly initially with 1/4 tank and worked better after I drove it a bit on the first E on full event.

Grounds check out so I don't think that's an issue. I can't blame the gauge because it's reading the 80ish ohms correctly.

I really don't want to take this sender/tank apart again. Any ideas or suggestions would be greatly appreciated.


http://forums.vintage-mustang.com/v...FjAAegQIBRAB&usg=AOvVaw0atNYEDJZRGcvWM-0pUt7z

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#3 ·
I can pipe in that I am having a similar issue, but I don't thin it is the speedhut gauge. My gauge worked solid for 3 years with my old tank before I put in the spectra. Unlike the OP, I've not had time to troubleshoot.

BTW

thomasshawn has exceeded their stored private messages quota and cannot accept further messages until they clear some space.

I can't send you a PM TS.
 
#4 ·
I can pipe in that I am having a similar issue, but I don't thin it is the speedhut gauge. My gauge worked solid for 3 years with my old tank before I put in the spectra. Unlike the OP, I've not had time to troubleshoot.



BTW



thomasshawn has exceeded their stored private messages quota and cannot accept further messages until they clear some space.



I can't send you a PM TS.


Weird. Says I’m fine on storage. Deleted a few anyway.
 
#10 ·
I haven't pulled the sending unit out because the tank is full.

I'm not discounting the gauge as a possibility but ohms at the sending unit read the same as under the dash and they're incorrect for the level of fuel. Hard to blame the gauge until the ohms are correct. It appears the gauge is displaying the same thing im seeing.

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#11 ·
perhaps then you have the wrong sending unit? test it to see what the level is when full and when empty, and then try programming the gauge to work with the sending unit as is. i also noted that you can manually program the to deal with what ever sending unit you are using that doesnt conform to the set programs in the gauge.
 
#12 ·
I have gotten access to another sending unit/pump assembly. I'll simply unplug mine and plug in new one. Outside the tank. Then I can run it through full and empty and see how gauge responds. If it works, then it's the sending unit. If not, then. It's the gauge.

I'll update on Wed or Thurs after I get my hands on the unit.

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#13 ·
I don't have the same sending unit as you, as I have a Tanks Inc tank with the top-mounted sending unit. But I too experience a similar problem sometimes. I think that the sending unit float gets stuck or doesn't float as well as it should, because sometimes the fuel level will show lower than it actually is. Brake checking myself a couple times fixes the issue, I assume by jostling it out of whatever unhappy position it's put itself in.

Does the same thing across multiple gauges, so it is not a gauge issue. If I work the sending unit manually outside of the tank, it reads perfectly - so I conclude that the issue is that the float doesn't float as well as it should when a liquid is involved.
 
#15 ·
You gotta slosh the gas around in there pretty good :p
 
#20 ·
Update:

So I hooked up the second sending unit today, (also a spectra). The gauge performed perfectly. Checked at full, empty and just above/below 1/2 a tank. The gauge responded appropriately.

So, as expected it's the sending unit. Now Why is unknown until I pull it and inspect.
Later maybe this weekend.


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#25 ·
so I got around to draining tank and pulling the sending unit.
was all prepared to trash the old unit. turns out it was nothing more than the float had popped off and that allowed the float arm to drop further down which gave a higher ohm reading than what should have been empty and why it stayed empty regardless. of course, I couldn't find the float in the tank. luckily I keep everything and I had an old sending unit that had been removed from the previous tank and that float fit perfectly. I did squeeze the arm a few mm tighter around the new float to keep it from falling off again (i hope)

took the opportunity to calibrate the tank empty/full according to the speedhut directions. so we'll see how this works.
 
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