gas gauge or sending unit? which is at fault? (2 Viewers)

[pbgbottle]

i would probably leave that white and black wire alone at the dash plug .may be the ground for the dash lights and indicator dash lights and either ground the sender to the frame or hunt down the white and black wire somewhere in the engine bay .and splice
the white with black wire from the sender to it .

 

[wantatlc]

i'll try to help out this seemed to work try it out .white with blue positive to gauge ,black one out of guage .to center conector on fuel sender ,then yellow wire attached to any one of the screws .back to ground . guage should work

the wires i used were just scrap pieces i had laying around . i cycled the fuel sender up and down and the gauge seemed to work

make sure the connectors under the nuts aren't contacting any other part of the circuit board . it may cause wacky readings

okay pbgbottle - PROGRESS. so here are my results, tell me what you think is the issue.

I did EXACTLY what you did. I just took the sending unit out and the dash out. Set them on the ground and did the same wiring. Results were that when I put the sending unit on Empty, it stays on Empty. When I put it on Full it slowly raises the needle!! BUT the needle stops at 1/2 way or so. Never really goes beyond that and not up to Full. When I try to hold at maybe 1/4, I get it to slowly drop back down, but it kind of wants to go to Empty (maybe becuase I cannot hold it perfect at 1/4).

When I hook up my tool for testing for power, and set the sending unit to Empty, I attach the clip to the ground on the sending unit and touch the power tab, I get BRIGHT power reading (bright bulb). But, when I put the sending unit to Full, I get FAINT power reading (bulb barley glows).

Wierdness is that when I does these tests with the tool for testing power, it makes the gas gauge needle creep up a bit??

WTF is going on do you suppose.

 

[pbgbottle]

. i'm not sure about everything but looking at the dash again where the gauge is .that 3rd stud is joined to the temp gauge . it might need to be connected to something power or ground .or it is just a power source for the temp gauge ? when i did my test the needle moved very slowly also ,i thought it was just an old sticky needle .but it did read full .maybe we are missing something . i took apart the setup . maybe when you are playing with it . check that third post just to see if it is hot when everything is hooked up . if it is then don't worry about it .probably just a power source for other guage . if not try grounding it and see if the needle is more responsive ?? don't blame me if ya fry something tho . other wise you might have a faulty sender you did say you heard crackling . i'm not to sure about all this either just trying to help a fellow cruiser head out . . tomorrow i will probably mess around a little bit with my .junk and see what i figure out . with the third post .

 

[wantatlc]

no blame on you. you have been major help and I appreciate it!!

I tried every option with no joy. I wonder if that sending unit is bad as the gauge seems to work (and I conclude this by the mere fact that it does move up and down and respond to the sending unit). So, if the sending unit is bad, it might be sending incomplete signals? maybe that crackling damaged it in some way, but the gauge still seems to work.

btw, even if I did get it to work on the ground out of the rig I do not know how I would get it to work in the rig with existing wiring? heck, would I have to run new wire just for the gauge and sending unit?

let me know what you come up with as I have tried all I can and wonder if I should pop for a sending unit? I will wait to hear if you do more complete testing and actually get your gauge to truly respond (more than just move) to the actual location of the sedning unit and report correct levels (1/4 or 3/4 or full or empty, etc.). mine moves, but not to the correct levels.