Hot Rod Forum banner
1 - 6 of 6 Posts

·
Registered
Joined
·
328 Posts
Discussion Starter · #1 ·
Dont know if this is the right forum for this post,Installed a new gas tank yesterday,gas guage worked before now it doesnt have rechecked all connections all seem fine.The gauge is all the way past the full mark,wont move to register the 3 gallons put in it to check for leaks.
 

·
Registered
Joined
·
1,189 Posts
First of all, did the gauge work when the car had the old rotten gas tank in it?
If not the sender (tank unit) may be bad. Also make sure the tank (it is steel, isn't it?)is grounded. If the tank is plastic you'll need to run a ground wire from a sending unit flange mounting bolt to a good ground point, no rust, no paint, on the frame.
 

·
Registered
Joined
·
7,345 Posts
Doc here, :pimp:

If the Gauge is pegged at full, you have an open sender wire ( on most types), to the tank, or are missing a properly bonded ground.

To test the system, remove the sender gauge off the sender..Note if the gauge moves at all, and in which direction..(most will go Full, some will go empty)..THEN..ground the sender wire...The Gauge should peg in the opposite direction. If you have that, The System is whole from the sender forward..

The Sender or tank ground then will be the offender..

To test the sender..

Run a Properly bonded ground jumper to the Fuel Line and Sender Egress Door, If the sender is a ring type, (no screws,) Find the ground Lug on the Sender unit..(should be a slide on terminal) .. Test the Fuel gauge again, If it reports accurate now, Install a new permanent Ground wire..


If Not, Next remove it, and with a DVOM, Set to OHMS , RX1 Scale, Calibrated to 000, Place one probe on the sender output, and the other on the Fuel Line and sender Egress Door (sender ground)

It will read anywhere between 0 and around 290 ohms, Or 290 ohms to 0..Then slowly move the float arm up and down, watching the meter, The resistance Should change in proportion with the float level..It should be slow and steady, no jumping or dropouts. If you have dead spots replace the sender.

Check to see if the float is not full of fuel.

When you installed the new tank, did it come with a sender installed or did you Install the old sender? If it came with the tank, It may be the wrong resistance value for your system , and needs to be replaced with the proper value and direction sender..If old, you may have damaged it in the swap, or hung it up on something installing it.

Doc :pimp:
 

·
Registered
Joined
·
328 Posts
Discussion Starter · #6 ·
Well thanks for your advise Doc,we had to remove the sender hooked up like u said gauge worked.Installed again didnt work,took back out and recheck sender turned out to be when u move the arm at a certain point was not getting contact.Took sender apart rebend and cleaned the strip that the arm rubs on when moving tested and it worked.Installed and kept testing untill we got the tank installed in the car and it was still working,We think ist calibrated preety close have about 3 gallons in a 18gallon tank gauge reading just under quartertank.Will be loking for new sender if this fixdoestn't last.Hope this all makes sense.
 
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top