Vintage Mustang Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Ride of the Month Challenge!

1 - 8 of 8 Posts

·
Premium Member
Joined
·
50 Posts
Discussion Starter #1
When I fill up my 1970 Mach 1 it never reads full on the gauge, always right around 3/4 full or less is as far as it gets. Anyone have this problem?
Is it a gauge problem or in tank float assembly or maybe both?
Thanks
 

·
Registered
Joined
·
36,500 Posts
These were never very accurate, and likely has got worse with age. If you want a real PITA project, pull the sender, and check it out. If it's getting full travel and isn't corroded, it's probably a gauge adjustment problem. I've done it, but it's a lot of work. How's the E end of the scale? That's the part that will get you in trouble.
 
  • Like
Reactions: Dave R.

·
Registered
Joined
·
37,701 Posts
The first thing I'd check is the sender resistance at a full tank. You should have in the neighborhood of 10 ohms. If not, the issue is probably with the float arm on the sender being misaligned. If you DO have around 10 ohms resistance and the gauge doesn't read at the "F" mark you can adjust the gauge high limit through the back of the housing with a small flat-head screwdriver. This will ALSO change the readings all across the scale so if your low-limit (the "E" mark around 65 ohms) you might have to adjust THAT one too.
 

·
Registered
Joined
·
42 Posts
Ditto here. Got new tank, new sender. Calibrated the gauge with sender on test tank. Looked good. Put it all back together on the car.
Ditto. reads like yours.:(
 

·
Registered
Joined
·
644 Posts
I pulled my fuel gauge a couple of years ago and "tweaked" the adjustments on the back of it. My gauge never read correct after that. A full tank would be past F and a 1/2 tank would be close to E.

Last weekend I added the MeterMatch device and calibrated the singal between sender unit and gauge. Well worth it.
 

·
Registered
Joined
·
10,341 Posts
You need to calibrate the sender before you put it install it in the tank. The shop manual shows the procedure and has the Ohm specs. Hook it up to the harness and test it before dropping it into the tank.You might also want to check the integrity of the sender to body ground through the harness. too much resistance will mess with the readings.
 

·
Registered
1967 GT500
Joined
·
1,363 Posts
I had problems with mine too. Checked out sender wires and gauge. All worked. I finally pulled the sender and bent the float arm to where it read right. Forgot if you bend it up or down. I think down. There are posts about it.
 
1 - 8 of 8 Posts
Top