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ArthritisMaster Samba Member
Joined: May 06, 2016 Posts: 80
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Posted: Wed Jun 22, 2016 4:57 pm Post subject: Fuel Gauge Problem Source? |
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Hello, I have a 1973 Type 1 Standard and my fuel gauge is very inaccurate. When the key is on or when the engine is on, the gauge needle goes to over a full tank and sometimes it says half full. I know that it is inaccurate because I only put about 3-4 gallons in at a time since it is a project car and the needle would move a significant amount if 3/10 or 4/10 of it is full. Since the needle on the gauge is working, I would say the sending unit or the vibrator is bad, but I cannot diagnose further from there. Also if it helps, the tank is not bolted down yet, would this make a difference in the way the sending unit operates? Thanks! |
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Bama Dave Samba Member
Joined: April 19, 2015 Posts: 963 Location: Alabama
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Posted: Wed Jun 22, 2016 5:26 pm Post subject: Re: Fuel Gauge Problem Source? |
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Is the sender grounded? _________________ David Richerson
1970 Beetle
1971 Super
1972 Baja
hellthorne wrote: |
First off, I know i made stupid decisions that led to my predicament, so while you are welcome to tell me that I am an idiot for doing the things I did, please know that I am already aware of this. |
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ArthritisMaster Samba Member
Joined: May 06, 2016 Posts: 80
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Posted: Wed Jun 22, 2016 6:21 pm Post subject: Re: Fuel Gauge Problem Source? |
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Ahh Dave, that is the thing, I thought it grounds to the tank via the screws that hold it in. Other than that, how can the unit be grounded if there is only one terminal on it? (The one that goes up to the vibrator.) |
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ArthritisMaster Samba Member
Joined: May 06, 2016 Posts: 80
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Posted: Wed Jun 22, 2016 6:29 pm Post subject: Re: Fuel Gauge Problem Source? |
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I just read on another thread that if the single wire connection on standards (unlike the double on supers) starts to act up, take another wire from a ground location and connect it to one of the sender screws that hold it into the tank, should I try this? |
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Tim Donahoe Samba Member
Joined: December 08, 2012 Posts: 11739 Location: Redding, CA
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Posted: Wed Jun 22, 2016 7:18 pm Post subject: Re: Fuel Gauge Problem Source? |
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Yep. _________________ Let's do the Time Warp again!
Richard O'Brien |
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ArthritisMaster Samba Member
Joined: May 06, 2016 Posts: 80
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Posted: Wed Jun 22, 2016 7:42 pm Post subject: Re: Fuel Gauge Problem Source? |
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Ok I will try this tomorrow and see how it plays out. |
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Tim Donahoe Samba Member
Joined: December 08, 2012 Posts: 11739 Location: Redding, CA
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Posted: Wed Jun 22, 2016 11:15 pm Post subject: Re: Fuel Gauge Problem Source? |
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Actually, a grounded wire to one of your screws would work, but VW did this:
One of the washers under one of the sender screws was metal. The tank where that screw was fitted had some paint removed where the washer would sit against. At least one of your brackets that hold your entire tank in, should also press against an unpainted portion of your tank. Thus, when everything was tightened, the ground was complete.
Although, as mentioned, a simple length of wire from a screw in the chassis--or any good ground-- connected to one of the sender screws would do the same thing. Just make sure the mating surfaces are clean and shiny.
Tim _________________ Let's do the Time Warp again!
Richard O'Brien |
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ArthritisMaster Samba Member
Joined: May 06, 2016 Posts: 80
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Posted: Thu Jun 23, 2016 8:17 pm Post subject: Re: Fuel Gauge Problem Source? |
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Well, today I did the ground and it still said past a full tank. I kept turning the power off and on again to see if there would be any different changes but the needle eventually started twitching and moving all over the place which was quite peculiar. Eventually it settled at a little below half a tank. I do not know if this is accurate or not since I just put a little more gas in today. _________________ 1973 Volkswagen Type 1
1600cc 1.6L
Manufactured: 02/73
*Restoration in Progress |
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Tim Donahoe Samba Member
Joined: December 08, 2012 Posts: 11739 Location: Redding, CA
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Posted: Thu Jun 23, 2016 9:34 pm Post subject: Re: Fuel Gauge Problem Source? |
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If it consistently shows a 1/2 tank, the then half of your sender rheostat is probably burnt out. And this is probably due to a burnt out vibrator.
Tim _________________ Let's do the Time Warp again!
Richard O'Brien |
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ArthritisMaster Samba Member
Joined: May 06, 2016 Posts: 80
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Posted: Fri Jun 24, 2016 11:55 am Post subject: Re: Fuel Gauge Problem Source? |
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Tim, I turned on the power today and it went past still a full tank, it doesn't stay at 1/2. When u turned the power off, the needle jerked it's way down to 0. The jerking of the needle may be an important clue. Who knows? _________________ 1973 Volkswagen Type 1
1600cc 1.6L
Manufactured: 02/73
*Restoration in Progress |
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Tim Donahoe Samba Member
Joined: December 08, 2012 Posts: 11739 Location: Redding, CA
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Posted: Fri Jun 24, 2016 4:09 pm Post subject: Re: Fuel Gauge Problem Source? |
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Replace the vibrator with a new-type black plastic encased vibrator--the kind with a small hump on its one metal side. Wolfgang International sells good ones. I believe Wolfsburg West does, too. The kind with the hump have a zenor diode, and are more expensive. But just a few bucks more.
It sounds like you may have an OEM metal vibrator that's on its way out. Replace it before it burns out your sender or gauge. Also, check for a short in the sender wire.
If this doesn't do it, then you also need a new sender.
Be sure when all is done that you have a good ground.
Tim _________________ Let's do the Time Warp again!
Richard O'Brien |
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ArthritisMaster Samba Member
Joined: May 06, 2016 Posts: 80
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Posted: Fri Jun 24, 2016 7:25 pm Post subject: Re: Fuel Gauge Problem Source? |
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Ahh, I see, I do in fact have an OEM vibrator, are you talking about one like this? https://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=113957099A _________________ 1973 Volkswagen Type 1
1600cc 1.6L
Manufactured: 02/73
*Restoration in Progress |
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Tim Donahoe Samba Member
Joined: December 08, 2012 Posts: 11739 Location: Redding, CA
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Posted: Fri Jun 24, 2016 9:19 pm Post subject: Re: Fuel Gauge Problem Source? |
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Yes, that's the correct vibrator. You can buy them cheaper, but that one has the little hump on the back. Buy it. You get what you pay for.
The new vibrator doesn't actually vibrate like the OEM ones. It's a different design with a light bulb inside to use off some voltage. If it fails, it passes no voltage at all, which saves your sender and gauge from getting a full 12 volts and saves the small wires from burning up.
Tim _________________ Let's do the Time Warp again!
Richard O'Brien |
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ArthritisMaster Samba Member
Joined: May 06, 2016 Posts: 80
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Posted: Sat Jun 25, 2016 9:36 pm Post subject: Re: Fuel Gauge Problem Source? |
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Mmm, I see, that will be on my next thing to do then, thanks. When I will get around to ordering it, who knows? But if it does the same thing again, I will know it is the sender unit right? _________________ 1973 Volkswagen Type 1
1600cc 1.6L
Manufactured: 02/73
*Restoration in Progress |
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Tim Donahoe Samba Member
Joined: December 08, 2012 Posts: 11739 Location: Redding, CA
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Posted: Sat Jun 25, 2016 9:46 pm Post subject: Re: Fuel Gauge Problem Source? |
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I played with this issue until I got some good advice from a guy on here who really knows his stuff. He convinced me that our fuel-gauge systems are a three-part piece of work. The sender, the vibrator, the gauge. In his opinion, all three should be replaced when you want it to work.
Since your gauge provides a full reading, I'd say you're okay there, however.
Change out the vibrator, and if, after that, you don't get decent readings at the gauge, then the sender is the issue--assuming your wires, connections, and ground is okay, that is.
A consistent full reading indicates a grounded control wire. You have checked the sender wire for nicks that might me contacting metal, correct?
Tim _________________ Let's do the Time Warp again!
Richard O'Brien |
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ArthritisMaster Samba Member
Joined: May 06, 2016 Posts: 80
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Posted: Sun Jun 26, 2016 12:15 pm Post subject: Re: Fuel Gauge Problem Source? |
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Well, I have now two wires from the sender. One is from the securing screws on it to a ground and the other is from the terminal on the sender to the vibrator. I use industrial grade wire because I could not find any other wire around (it is also brand new) so there is most likely no exposed wire. _________________ 1973 Volkswagen Type 1
1600cc 1.6L
Manufactured: 02/73
*Restoration in Progress |
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