ghost in the machine ?

[ab59]

maybe next payday as I have been 20 , 50 and a hundred dollared to death this month. A lot more affordable though.

 

[ab59]

Well , I received and mounted my new fuel sending unit and float . I does NOT work . Looks like the ghost is back. Sending unit jumped to ground and gauge jumps to full so gauge is good , Right ? New Sending unit so sending unit is good right ? Hmmmmm. I read that if the gauge jumps to full when the sending unit is jumped then the wires are correct as well . I may call the men in the little white suits and the rubber rooms pretty dang quick at this rate.
I crawled up under the consoles again but don't see anything that could be a problem . I even removed the gauge looking for a bad connection but am baffled by this one.Gauge tests good , sender tests good but no reading on the gauge. Nothing I can find in the books for this one. got to be a simple solution but I don't see it.

 

[alldodge]

You jump the gauge to ground and it pegs full
Jump the sender to ground and the gauge pegs full

If both are correct, then there is a ghost, otherwise its not going to ground

 

[ab59]

I am going out to make a couple of jumper wires for my harness to gauge since the harness is a 3 way solid plug to the back of the gauge and not enough slack to work with . sender to gauge pegs the gauge to full quickly. I thought that was the test. Did not know I needed to jump the gauge as well. I did try to test the plug and got sparks when I tested the hot wire into the plug and ground . no reading on the meter. did not expect that one.
I'm headed out.

 

[ab59]

just too poor of light conditions now , best test I got was 3 ohms at the harness so I'm not getting a good test. Will get back on it tomorrow. It does concern me that the wiring at the sender is not the same color at the gauge and for some reason someone has two more grounds at the sending unit flange along with the sender ground . That makes 3. I also observed that there was a taped up place where someone had scraped the insulation off of what I believe to be the supply wire most likely to test the wire . There are two pink wires and one gray at the gauge. the larger pink appears to be the power in and I guess the other smaller pink to be the sender and the gray ground. Sending unit wires are red and black, no pink. I have a feeling that I may have to unwrap the harness to trace the wires to see what has been done to this . Thinking of running yet another pair of wires from the tanks to the gauge . I dunno . I will hope tomorrow is a more successful day.

 

[alldodge]

Does sound like someone has been messing around either trying to fix the same issue or causing it. The sender only needs 2 wires, ground and sense. With ground already there could just run a new wire up to the gauge

 

[ab59]

I must be missing something very basic . I could not get the gauge to move to full by jumping it when installed in the harness. I removed the gauge from the panel , went straight from the sending unit to the gauge including ground , brought a hot wire from the plug and when I jump the sender to the ground without removing the wire from the sender I get the gauge to jump to full. No matter what I do , I cannot get the gauge to read the level of gas in the tank which is about 3 inches in an 8 " deep tank. I don't have an old gauge laying around right now or I would try another gauge and see if that made a difference . I could buy another gauge to see but do not want to waste any more money.
Something I just don't get. bypassed all the wiring except the power in and still can't get the gauge to read fuel level and yet the gauge will go to full when jumped sender to ground.
The gauge should work because it tests good but it does not work . I must be overlooking something simple .
One thing noted , I connected my ground jumper to the wire and not the sending unit flange and it worked as if the ground wire was already grounded . Does that mean anything other than I'm a dumbass ?

 

[ab59]

I just went down to a local auto parts store and bought another fuel gauge . they only had one . when hooked up it reads past full unlike the original that lays there on empty. I guess the new gauge is for another ohm range so back it goes and so true to course I still don't have an answer. Looks like I have to order another gauge, too bad I can't buy one that matches the original square face.

 

[alldodge]

A boat uses 180 (empty) to 33 (full) ohm scale. Many cars use different if not opposite scale. So it would show empty if grounded. This is how the gauge/sender should be wired. You should have 12V on the purple wire when the key is ON

 

[ab59]

looks like what I've got. I even hooked the gauge up direct bypassing the harness and although it did not read the fuel level it did peg out to full when jumped sending unit to ground. I am looking for another gauge and trying to find one with a square bezel to match what I have. it's got to be a bad gauge, doesn't it ?

 

[alldodge]

Pull the sending unit from the tank and get away from the boat. Connect up the gauge and sender to see if when the level is raised or lower if things change

 

[ab59]

Ok. To be clear , you do mean that I should still bring the hot wire to the gauge , right ? But just away from the tank. I saw a guy on the internet testing the sender at different levels and it looked like he did not have any juice going to it as he tested it.

 

[alldodge]

Do it simple and safe. Pull the sender and take it and the gauge over to a bench. Connect 12V and ground from a battery to the gauge. Connect the sender to the gauge sender terminal and a ground to the outside connection. Now move the sender by hand to see how the gauge changes

 

[ab59]

you must be reading my mind , I was just going to go to the bow and test and throw the inspection plate over the sender access hole . I will just use my battery charger as a 12v source and take everything over to my work table.
I got a little side tracked by my new alternator arriving and installed it ( with only a few difficulties ) instead of working on the sender. I did get the sender out though before the alternator arrived. Will test the sender before dark but after my water break.

Thanks----

 

[ab59]

Ok. I didn't blow myself or the little woman's pest of a black cat up . After all the times I have hooked this up , over and over again , now it works ? I really don't quite understand all I know about what I' doin . Glad someone does . I laid everything out hooked it up like I did before but this time the gauge works like it should 1/4, 1/2 3/4 ,it's all good !
When I put this back in tomorrow I will test the sending unit wire again and make sure it has the correct amount of power. Sure would have been a good idea if I would have done all this when I had the deck out and access to the harness but lesson learned for the future i guess.
Somehow I'm missing something simple and tomorrow I'm going to find out what or I will remove all the wires to the sender from the gauge and run my own so I know what i have.
I am still not leaving out the possibility of a PO tieing into the harness wrong when the ran new wires to the sender and harness in the past. I may untape the harness and look at where they did their connections .

 

[ab59]

And right back to gauge not working. Once again , after mounting the sender back into the tank , nothing happens with key on . i bypass the loom and go directly from the positive stud on the back of the gauge to the sender at the tank and nothing. I cut a foot or two of the harness tape looking for something obvious and nothing.
I tested the hot at the gauge plug and get 11 v ( key on ) going in and 7.5 v going to the sender , so why don't the gauge work ?
I noticed that the plug fits very loosely on the back of the gauge and I have decided to cut it off and use connectors so I can be sure of good contact. In this way I can ground it out under the dash in a different place to see if that is the problem.
At the sender, I guess that the red wire at the sender may be an old faded , discolored Pink wire as I traced it over to the huil before it heads back to the battery and it looks pink where it has been protected from the elements but still not sure if it is original or not. It also looks like someone may have tapped into the pink wire to get juice for a CB radio , I have not fully investigated that as of yet and I did trace down the two other grounds at the tank and they come out in the ski locker and are screwed into the aluminum wall there , maybe that is grounding the tank i dunno.
Going back out ------

 

[ab59]

well let's just pile it on shall we. I was charging the battery as I looked through the wiring earlier and I had left the key on. I took a water break and when I came back I noticed that the charger was really putting out juice and I checked the key switch to find it was pretty hot to the touch. I went back and disconnected the positive on the battery and inadvertently put my hand on the new alternator that I had just installed yesterday and found it VERY warm close to the point of burning my hand after a few seconds .
It is as if every night someone goes out to the boat and does something to it as I sleep. I may have to take a break before I do something drastic here.

 

[alldodge]

I would not use the pink wire going to the sender/gauge and cut it loose from both ends. Use a new wire and also may need to run a new ground to the tank.

Things getting hot may be back feeding something

 

[ab59]

Wonder what happened to the 4 pictures that I posted along with the successful gauge tests . Odd.

 

[alldodge]

They should probably come back. Many times things vanish and re-appear later