Guys, does the fuel sender need to be grounded on my 57 wagon? I'm replacing the sender but there is currently no ground wire from the sender to the frame or the floor pan. The 57 Chevy Workshop Manual shows that the sender is supposed to be grounded. If it is to be grounded, should it be grounded to the frame or the floorpan? Im thinking it should be the frame as the body is mounted on rubber biscuits then bolted to the frame. The sender is new, but even when full it hovers around the middle of the gauge. I trialled a ground wire to the floorpan (bare metal) and it went to just above empty even with over 1/2 tank of fuel in it. Ive tested the gauge and it works correctly. What gives? Anyone help as I need to know asap. Thanx in advance... Rat
your sender/fuel gauge is working because it's probably being grounded through the steel fuel tank, then to the steel frame..but why rely on that? i'd run a ground wire from the one of the mounting bolts on the flange of the sender to the frame you can never have too many grounds your frame/motor/body/negative side of the battery should be all grounded together. i like to run the negative side of the battery right to the motor with 0 or 1 cable. then from that same place on the motor run a grounding strap to the frame. and from the same place on the motor a ground strap the the body
Well its grounded now to the floorpan....but only reads just above Empty when I know there is 40 ltrs of fuel in the tank. Now what?
is it the correct sender? an original `57 chevy used a sender that was 0 ohms empty and 30 ohms full..that was in the USA , maybe down there was different. are you using the original fuel gauge , or something different? is the gauge wired correctly? is it a new sender or an old crappy worn out one?
The sender AND the gauge must be grounded, so make the sending unit ground to the body, cuz the gauge is in the body
If the gauge was not grounded an exaggerated reading would result, showing more than what was there due to the gauge going to ground through the sender instead of its own ground. I am gonna say you have a stock sender 0-30 ohms and an after market gauge or replacement for your stock cluster that is 0-90 ohms. This is making it read roughly 1/3 tank at full and hardly any if at half. If not then we need more info..
"An electrical headache can make a great car a pain in the ass" Tell me about it JAWS hahaha...this sender/gauge issue is really giving me the shits. Sender is repro - replacement and should be 0-30 ohms . The gauge is original 57 Chevy. BEFORE I added the ground wire, regardless of how much fuel it has it would fluctuate b/w under half and above half. Now that the sender is grounded to clean metal on the floorpan, it sits just above empty all the time. I tested the float for leaks BEFORE I fitted the repro sender and it passed OK.....some of those repro senders had leaky floats and were a PITA. Any tips? Rat
Should not need a extra ground. However did you put any thing between the tank and body when you had the tank out? If so you lost the ground. Your tank mounting straps also make ground. With the sending unit out hook up a ground to it and move the float up and down with the key on. Should the gauge be bad this will show you.
The sending unit is ground for the gage. Don't add another ground that'l short the circuit and that is why the gage reads empty when you add another ground. The 'hot' is at the gage and the sender provides 'ground' with various amounts of resistance (0-30ohms for early chevy, 0 being empty). If you have a new gage what you are probably dealing with is a different resistance value, modern standard is something like 230-30 when full. As usual it is more complicated than it should be.
It has to be grounded. Originally it was grounded through the screws that hold it to the tank, from the tank to the support straps to the frame. Adding a ground from one of the sender mount screws to the frame can insure that the original ground isn't lost.
Nope as stated the gauge is the original one and it works. There is nothing b/w the tank and the floorpan - I checked that when I dropped the tank. Since the body is mounted on rubber "biscuits" on the frame, should I ground the sender to the frame and not the floorpan? Any other thoughts? Rat
As was said before, you can never have too many grounds. just make sure you ground the mount, not the post. check that the sender isn't touching the floor. I had to clearance my floor because the aftermarket sender was just a touch too tall. make sure the wiring isn't backwards, i did that the first time by accident. empty when full, full when empty.
did you have the tank out and used some sort of sealer on it? maybe the sender float is sticking to the bottom of the tank. i had that happen once , i banged the bottom of the tank with my hand where the float would be and fuel gauge started working and yes, the body of the fuel gauge needs to be grounded too..ther should be three connections on the fuel gauge: 12 volt switched power , ground and the wire from the sender
To prevent any other grounding issues, I always run a bonding strap (heavy duty no smaller than 10gauge) from the car body/firewall to the frame. I route the ground battery cable to frame and another battery ground cable from frame to motor mount/starter mount stud/ or bellhousing bolt.
Make sure the power wire to the fuel sender doesnt have a bare spot in the insulation and is touching metal where it goes through the grommet in the trunk floor or any other area.My 55 had that problem.The gauge and fuel sender were fine. The body is already grounded with the braded negative battery cable to the firewall,unless it has been moved to the engine. My bet is the power feed is grounding somewhere.
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