Fuel tank sending unit adjustment

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Old Sep 5, 2014 | 10:13 AM
  #1  
442craig's Avatar
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Fuel tank sending unit adjustment

Hi Guys,

Put in a new gas tank and new sending unit in my '68 442. It reads 3/4 when full. I would assume that I need to bend it down to calibrate it. Is there a way to adjust it once and not have to keep pulling the tank and adjusting?

Thanks,

Craig
Old Sep 5, 2014 | 11:15 AM
  #2  
Allan R's Avatar
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It should work properly if it's new. Call the vendor who sold it to you and ask them for a remedy (like a new sender). The float in the sender will only move so far, and if it's not reading full when the tank is full, the sender itself may be bad.
Old Sep 5, 2014 | 11:21 AM
  #3  
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Neither approach is wrong, however if it breaks both pieces are yours if you don't do what Allan suggests first.
Old Sep 5, 2014 | 02:31 PM
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I bought the tank at Impala Bob's and The sending unit from OPGI. I am assuming the tank was probably made where all the re-pops are made.

I'll call OPGI

Thanks!
Old Sep 6, 2014 | 07:06 AM
  #5  
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I had the same problem, and on my car, it was the gauge itself that was defective. The only way to know if it is the gauge is to work the unit out of the thank, and see where the limits are. Then using another sending unit, do the same thing. If both sending units react the same on the gauge, there is a strong possibility that it is the gauge. I was lucky enough to have two sending units in my stash to try. I also had a spare dash to use the gas gauge from, and when I changed it, the problem went away.
Old Sep 6, 2014 | 09:01 AM
  #6  
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Simple method to check the gauge is to ground the feed wire it should drive the gauge to empty or past, disconnect the feed wire (open circuit), it should go past full.
Old Sep 6, 2014 | 10:41 AM
  #7  
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The gauge worked fine before I replaced the tank. I think I threw the old unit away
Old Sep 10, 2014 | 09:43 AM
  #8  
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Update

Hi Guys,

So got the hard lines in yesterday. I got a set from Inline tube. I ended up unbolting the body and jacking it up a few inches for wiggle room. It was actually easier than I thought. The hardest part was bolting the the line clips back in.

Mission accomplished! Now on to fixing the rich idle on the Q-jet!

Thanks for the input!

Craig
Old Sep 10, 2014 | 09:46 AM
  #9  
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One more thing, I also bent the fuel sending unit to see if it fixes my 3/4 full problem.
Old Sep 10, 2014 | 12:15 PM
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So did bending the sending unit float solve the problem? I'm thinking no. If it was registering 3/4 on a full tank, either the float arm is binding somewhere or it's not at 90 ohm.
Old Sep 10, 2014 | 01:56 PM
  #11  
442craig's Avatar
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I still have to put it back in the car. I'll let you know.
Old Sep 10, 2014 | 06:42 PM
  #12  
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I bought mine from impala Bobs as well.The float arm is bent incorrectly and will hit the top of the tank before it reads full.They sent me another one with exactly the same problem.I finally just bent the float arm to match the original sending unit and it worked fine.
Poor quality reproduction parts as always. I don't think anyone actually tests parts before bringing the part to market.

Last edited by 72w442; Sep 10, 2014 at 06:43 PM. Reason: spelling
Old Sep 10, 2014 | 08:00 PM
  #13  
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I bought the tank from Impala Bob's and a sending unit. The unit they sent was a single line so I sent it back and ordered a dual line from OPGI. They probably are all from the same manufacturer.
Old Sep 11, 2014 | 02:07 PM
  #14  
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Originally Posted by 442craig
They probably are all from the same manufacturer.
I sure hope not. The one I ordered from ILT was spot on with construction and float arm etc. I kept the original, just in case.
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