Fuel gauge adjustment/calibration

Tech tips and how to's

Moderators: notoptoy, S Allen, Solex68

Post Reply
kingsey2k
Roadster Newby
Posts: 12
Joined: Thu Feb 08, 2018 2:02 am

Fuel gauge adjustment/calibration

Post by kingsey2k »

I've got a '70 2000 with the stock fuel gauge, tank, sender... Mechanic recently redid the tank to get the rust out of it, but since I got it back, when the tank is filled, the gauge is reading as 3/4 full. If I can ask, is this something to do with the sender/float or can it be adjusted on the back of the gauge itself? Otherwise the gauge seems to function properly.
JT68
Talented Enthusiast
Posts: 2920
Joined: Sun Jan 27, 2013 9:43 am
Location: Cumming, GA

Re: Fuel gauge adjustment/calibration

Post by JT68 »

Yes, there is an adjustment on the back of the gauge for "full" and "empty" positions.
LT/JT
https://www.datsunrestorationproducts.com/
Only the very BEST parts for your Datsun- 10000's of items in stock
New, Used and Reproduction!
User avatar
jhayden
Site Supporter
Posts: 477
Joined: Tue Oct 25, 2011 4:16 pm
Location: Tyler, TX

Re: Fuel gauge adjustment/calibration

Post by jhayden »

JT is correct on the gauge adjustment. Prior to doing that, try grounding the sensor wire. If it swings to "Full", the problem is likely in the sending unit, which would be suspect anyway, given that you just had the tank serviced. (The sending unit can be cleaned CAREFULLY.)
User avatar
Linda
Fraternal Den Mother-RIP
Posts: 7807
Joined: Sat Nov 05, 2005 11:37 pm
Location: Los Angeles
Model: 1500/1600
Year: High Windshield-68-70

Re: Fuel gauge adjustment/calibration

Post by Linda »

And how would you carefully clean the sending unit? Could you soak it in EvapoRust then wipe it down or use a toothbrush on it?
Linda
Sadly-Linda has passed away 2022. She was the 311's den mother and drove the first Rare-Parts ball joint project. RIP.
User avatar
jhayden
Site Supporter
Posts: 477
Joined: Tue Oct 25, 2011 4:16 pm
Location: Tyler, TX

Re: Fuel gauge adjustment/calibration

Post by jhayden »

Probably as many strong personal preferences for a particular cleaner as for penetrating oil. If the sending unit is bad order b/c of rust, EvapoRust or vinegar can be used. Mine have always been caused by gummed fuel deposits, and this product has produced good results for me (when brushed on full strength with the sender out of the tank):

https://www.berrymanproducts.com/produc ... p-t-f-s-c/

Honestly, the list of precautions is so long that anyone who is doing this for the first time may well be advised to purchase the following (and be done with it!):

https://www.datsunparts.com/1366
User avatar
notoptoy
Vendor-Site Supporter
Posts: 9674
Joined: Fri Oct 02, 2009 2:55 pm
Location: Winston-Salem, NC and Ocala, FL
Contact:

Re: Fuel gauge adjustment/calibration

Post by notoptoy »

I getcha John, that SDS is long and scary!
"When all else fails, force prevails!" Ummm, we're gonna need a bigger hammer here.

67.5 SPL311 H20 w/5 speed
65 Impala Convertible
2017 C43 AMG
kingsey2k
Roadster Newby
Posts: 12
Joined: Thu Feb 08, 2018 2:02 am

Re: Fuel gauge adjustment/calibration

Post by kingsey2k »

JT68 wrote: Fri Oct 16, 2020 5:50 pm Yes, there is an adjustment on the back of the gauge for "full" and "empty" positions.
Thank you!
kingsey2k
Roadster Newby
Posts: 12
Joined: Thu Feb 08, 2018 2:02 am

Re: Fuel gauge adjustment/calibration

Post by kingsey2k »

jhayden wrote: Fri Oct 16, 2020 8:13 pm JT is correct on the gauge adjustment. Prior to doing that, try grounding the sensor wire. If it swings to "Full", the problem is likely in the sending unit, which would be suspect anyway, given that you just had the tank serviced. (The sending unit can be cleaned CAREFULLY.)
Gotcha, much appreciate the advice.
jayedeluxe
Roadster Nut
Posts: 56
Joined: Sun Apr 12, 2020 3:50 pm
Location: san diego
Model: 2000
Year: High Windshield-68-70

Re: Fuel gauge adjustment/calibration

Post by jayedeluxe »

Question......is the "empty adjustment only to be done when the tank is actually empty and voltage is going through the sending unit ? Or can it be done with key off, and no voltage to sending unit ?
User avatar
23yrRebuild
Roadster Fanatic-Site Supporter
Posts: 1067
Joined: Sat Oct 25, 2003 2:19 pm
Location: 3rd rock from the sun
Model: 1500/1600
Year: Low Windshield-64-67.5

Re: Fuel gauge adjustment/calibration

Post by 23yrRebuild »

Mine is an early '67, but after Jon Frampton restored my gauges, I adjusted my fuel gauge so the pointer just touched the upper, right end of the "E" , while there was exactly 1 1/2 gals in the tank. The key need to be "on".
YMMV (Your Mileage May Vary !...get it :?: :lol:
Mike
Mike - '67 Stroker / 5-Speed
Post Reply