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Wed Feb 27, 2008 10:17 am

How do I know if my sending unit is good? My gauge only reads 3/4 when it's full and goes to empty with about a half a tank. My gauge needle also bounces around quite a bit. I've already checked the gauge ground and it's OK

Wed Feb 27, 2008 10:55 am

It's prolly dirty and/or corroded. The extremely fine wires inside it get that way after some 40+ years and only give a signal where clean. You can clean them up being very careful so as not to break them, or you can just replace the sending unit for a new one. Good luck! 8)

Wed Feb 27, 2008 12:42 pm

pyrOman wrote: It's prolly dirty and/or corroded. The extremely fine wires inside it get that way after some 40+ years and only give a signal where clean. You can clean them up being very careful so as not to break them, or you can just replace the sending unit for a new one. Good luck! 8)

Since a new sender is only $31 at busdepot, if I'm pulling the engine and tank to work on the sender, I'm putting in a new one. Be sure to release the float on the new one or you'll be pulling it out again!

Wed Feb 27, 2008 3:52 pm

dstefun wrote: pyrOman wrote: It's prolly dirty and/or corroded. The extremely fine wires inside it get that way after some 40+ years and only give a signal where clean. You can clean them up being very careful so as not to break them, or you can just replace the sending unit for a new one. Good luck! 8)

Since a new sender is only $31 at busdepot, if I'm pulling the engine and tank to work on the sender, I'm putting in a new one. Be sure to release the float on the new one or you'll be pulling it out again!

Dave, what do you mean by releasing the float?

Wed Feb 27, 2008 4:22 pm

sorry to but in it is a pin that is stickered to hold the float for shipping...how do i know? wellllllllll. luckily i was still able to pull it out without removing the engine or tank. 271-919-051b for $28 at wcm for a VDO of brazil. :wink:

Wed Feb 27, 2008 5:04 pm

420GOAT wrote: luckily i was still able to pull it out without removing the engine or tank.

The pin or the sending unit?

Wed Feb 27, 2008 5:38 pm

zozo wrote: 420GOAT wrote: luckily i was still able to pull it out without removing the engine or tank.

The pin or the sending unit?

I'm assuming the pin. If I could get the whole unit out, yes I'd just replace it. But pulling the motor and tank might be a bit beyond for me, I'm still reading up on valve adjustments :)

Wed Feb 27, 2008 7:08 pm

wanta23 wrote: If I could get the whole unit out, yes I'd just replace it. But pulling the motor and tank might be a bit beyond for me, I'm still reading up on valve adjustments :)

Then follow this procedure: Carry with you a gallon jug of gas. Fill up the tank, note the odometer reading down. Drive the bus to work, around town, etc., the way that you'd normally drive. Drive it all the way until it runs out of gas. Note the odometer reading down at this point. Figure out how many actual miles your bus will go on a full tank of gas. Pour the gallon of gas into it and go fill up the tank. Note the odometer reading now and every time you fill up. This way you'll know when to fill up BEFORE running out of gas. 8)

Though my gauge "reads" okay, I still always carry a gallon and also note the odometer reading at every fill up. :)

Wed Feb 27, 2008 7:56 pm

Mine reads 3/4 too, but when I throw the headlights on, it reads full. Zany Splits. :roll:

Wed Feb 27, 2008 11:23 pm

I have the exact problem with my gauge....I usually just fill up when my needle gets to 1/4.

My questions is .... do you have to remove the tank to replace the sending unit?

Thanks

Wed Feb 27, 2008 11:38 pm

Same as upgrading to a larger bay tank here: http://www.vintagebus.com/howto/tank.html
Just go for the R&R part :)

Wed Feb 27, 2008 11:47 pm

I replaced the sending unit and swapped gauges but my fuel gauge still only reads accurately between 1/4 and 3/4. Above and below that it can't be trusted.

Thu Feb 28, 2008 7:12 am

joe cool wrote: I replaced the sending unit and swapped gauges but my fuel gauge still only reads accurately between 1/4 and 3/4. Above and below that it can't be trusted.

Refer to my previous post! :?

The Dormy has a custom made 17.5 gallon aluminum tank and uses a bug sender. Also, not having any baffles causes the sender and thus the gauge needle to bounce quite a bit. Though I do keep track of how many miles since the last fill up, I know I HAVE TO get gas real soon when the needle stops bouncing!!! :shock:

Mon Jan 05, 2009 6:09 pm

Is there a way to test the sending unit outside of the bus? For that matter it is outside of the tank. I took it apart yesterday. Verified the tiny wire is in place and lightly cleaned the contact points on the float. As best I could, I verified continuity through the wire and terminal (old shoddy tester - I'm bringing another home tonight). It seems pretty simple.

Am I correct in thinking, "If the wire is in place, and the float goes up and down, and all the connections are clean it should work." Otherwise, any other tips?

1967 bus. Thanks,
Mike

Mon Jan 05, 2009 6:20 pm

Vintage Split wrote: Is there a way to test the sending unit outside of the bus? For that matter it is outside of the tank. I took it apart yesterday. Verified the tiny wire is in place and lightly cleaned the contact points on the float. As best I could, I verified continuity through the wire and terminal (old shoddy tester - I'm bringing another home tonight). It seems pretty simple.

Am I correct in thinking, "If the wire is in place, and the float goes up and down, and all the connections are clean it should work." Otherwise, any other tips?

1967 bus. Thanks,
Mike
I've tested a sender outside a bus with a battery, a fuel guage and a bucket of water.

You can take the tube off the sender by uncrimping the 'washer' and undoing the nut at the end. You can polish up the wire and contact places with fine (1000 grit) sandpaper to restore the connections. That's what I did to the sender in my kombi, that was previously in a bus with a cruddy tank.

Mon Jan 05, 2009 6:28 pm

Clara wrote:
I've tested a sender outside a bus with a battery, a fuel guage and a bucket of water.

The internals look good so I'll test it like you suggested next.

Thanks,
Mike

Mon Jan 05, 2009 6:28 pm

I've got a Baywindow tank (15 gallons) and sender (expensive little B) and a 6v bus gauge (12-90 ohms I believe). I had a 12v bus gauge before and they read the same...R means I have 3 gallons in the tank and a full tank reads almost full on the gauge. I will try a GM 0-90 ohm gauge next to see how it reads.

I also keep a mileage log as a back up.

Mon Jan 05, 2009 10:43 pm

Vintage Split wrote: Clara wrote:
I've tested a sender outside a bus with a battery, a fuel guage and a bucket of water.

The internals look good so I'll test it like you suggested next.

Thanks,
Mike

Hmmm, so I did the test and all that it verified is my gauge works. Basically went to full once I connected the battery regardless of the float level. I double checked the wiring diagram. Ground to sender, sender to gauge, gauge to + on battery. Correct? Am I missing something, or this is an ok test?

Mon Jan 05, 2009 10:48 pm

Vintage Split wrote: Vintage Split wrote: Clara wrote:
I've tested a sender outside a bus with a battery, a fuel guage and a bucket of water.

The internals look good so I'll test it like you suggested next.

Thanks,
Mike

Hmmm, so I did the test and all that it verified is my gauge works. Basically went to full once I connected the battery regardless of the float level. I double checked the wiring diagram. Ground to sender, sender to gauge, gauge to + on battery. Correct? Am I missing something, or this is an ok test?
did you ground the guage? you know how the guage grounds where the U clamp hits the underside of the dash? ... clip a ground wire to one of the studs the U bracket goes on, and see if that works.

Mon Jan 05, 2009 11:05 pm

Clara wrote: Vintage Split wrote: Vintage Split wrote: Clara wrote:
I've tested a sender outside a bus with a battery, a fuel guage and a bucket of water.

The internals look good so I'll test it like you suggested next.

Thanks,
Mike

Hmmm, so I did the test and all that it verified is my gauge works. Basically went to full once I connected the battery regardless of the float level. I double checked the wiring diagram. Ground to sender, sender to gauge, gauge to + on battery. Correct? Am I missing something, or this is an ok test?
did you ground the guage? you know how the guage grounds where the U clamp hits the underside of the dash? ... clip a ground wire to one of the studs the U bracket goes on, and see if that works.

Doh! That worked Clara. I was working inside my wife's Toyota (available battery) and didn't ground the gauge like you said. Now I can put the tank back in... one step closer.

Thanks.
Mike