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Thu Oct 22, 2009 5:46 pm

timo78 wrote: RatCamper wrote: so it's meant to be 10v? Pretty easy. Thanks.

I believe 10v is what the stock voltage stabilizer wants to deliver. Thats what mine had shown prior to getting fouled.

Radio Shack has them here but it is 12 volt in, 12 volt out , 1 amp. Is 12 volt out too high, or does it have to be a 10 volt regulator?

Thu Oct 22, 2009 7:48 pm

I was about @ 1/2 tank and just filled up -- 8.8 gallons. Hmm..? Going on a road trip this weekend [ Gas can -check!] and will see what the high/lows really are. Better than non functioning for me, but not perfect either, and I like 'better than average'.

Mine read high when full as well, but it had read OK before I put the dash back together, so I thought that was an anomaly.
But I am now thinking even 10v is too much. The night before I picked it up I was playing with this: http://www.ohmslawcalculator.com/ohms_law_calculator.php Which helped me comprehend how much wattage is going through the heating element. I guess pure 10v could be too much. I may try putting a little potentiometer POT in it to induce a bit more resistance, maybe 1-2 more ohms, between the VR module and the gauge. Or leave it alone depending on what my readings are around 240-80 miles into this weekends road trip.

I tested 10v when mine was still working and went with that, but I know now that the vibrator is not a "true" regulator. 12 volts goes through the mechanism and it opens and closes frequently to come to an average value.

Anyone know of the voltage that a voltage stabilizer / vibrator should deliver?

EDIT: just read this http://www.type2.com/library/misc/vwggauge.htm and it seems that 10v is about right, but the vibrator adds resistance too. I need to add some resistance...

Thu Oct 22, 2009 8:22 pm

They actually have a 5 volt out and a 12 volt out... Is the 5 volt out looking more close then?

Sun Oct 25, 2009 8:29 pm

Update:
Added a 30 ohm trimmer potentiometer [$2.49]. Connected off of the gas gauge on the tank sender side. To trim it back to a realistic [F]ull reading I added about 3-4 ohms. I hope that this will trim it back to a more reasonable 7 gallons at 1/2 tank fill up.

Mon Oct 26, 2009 10:17 am

Let us [me] know how it goes. The whole famn damily is sick and it's been raining so I haven't done diddly with any of my cars. Just sitting on the couch and watching SpeedRacer and Cars w/my boy.

Mon Oct 26, 2009 6:49 pm

magnus0328 wrote: Radio Shack has them here but it is 12 volt in, 12 volt out , 1 amp. Is 12 volt out too high, or does it have to be a 10 volt regulator?

--

They actually have a 5 volt out and a 12 volt out... Is the 5 volt out looking more close then?

Based on what I've seen, 12 is WAYwayWAY too high. It would be Full... A LOT!
and 5 is probably too low.

So far I had added the 10v VR to the system, which is resisted by 11 Ohms -coming from the sender in the tank when full.
Mr Ohms states that would equal about 9 watts. Which is the heat delivered to the gauge mechanism. Mine read visually over Full in this case. I then added the Potentiometer, to makes things better. Using it to trim the gas gauge needle back to a visual Full -needle-> on F.
I checked the POT and it was around 4 ohms. So if we add 4 ohms to the original 11 we get 15 ohms. That calculates into 6.5 watts. If you now take that value and send it back through Ohms law using 11 Ohms [The original Full tank resistance], you achieve a different voltage, about 8.5.
What does this mean? not much, but Ohms law is pretty cool :D or use an 8v VR
I am hoping that the POT will get me to the promised land of Fuel gauge happy town.

Thu Nov 05, 2009 6:10 pm

Hey Toby > Air_Cooled_Nut
I made a couple hundred mile trip this weekend. And upon fill up it was still reading a bit high, so I twisted the potentiometer to add a few more ohms. to where the needle was at 1/1 [Full] on level ground. After the next 110 miles I was almost at half tank. If yours is still reading high adding the POT will help. A 100 ohm POT is what I added, but only used the 30ohms side [this one was two sided] I am guessing I have around 8-10 ohms added now and it is spot on. Good luck!

Fri Nov 06, 2009 12:59 am

FUK you mean there is a 2 wire solution!!!!

I tried the radioshack 3 wire one with the resistor blah blah, but ended up going with a cell phone charger at 9.5v for now LOL.

Fri Nov 06, 2009 7:50 pm

timo78 wrote: Hey Toby > Air_Cooled_Nut
I made a couple hundred mile trip this weekend. And upon fill up it was still reading a bit high, so I twisted the potentiometer to add a few more ohms. to where the needle was at 1/1 [Full] on level ground. After the next 110 miles I was almost at half tank. If yours is still reading high adding the POT will help. A 100 ohm POT is what I added, but only used the 30ohms side [this one was two sided] I am guessing I have around 8-10 ohms added now and it is spot on. Good luck!
So you have added 10 ohms of resistence (and not 30 ohms), right?

I was out for a week due to the flu, then my fiancé gave me her pneumonia, so I haven't done diddly w/the Bus. I'm feeling better now (antibiotics and steroids are wun-der-full!) so I can hit the local Radio Shack and get a resistor.

Thu Dec 17, 2009 8:06 pm

Finally ran out of gas (carrying a spare gallon with me so no probs). Fuel gauge needle was right on the right white line of the red zone. That is empty as far as the sender is concerned. So with the needle pegging beyond Full when topped off it looks like a little calibration is in order. So someone here who has the same electronic device <ah-HEM! :wink: > needs to tell us (me) what size resistor to use.

Thu Dec 17, 2009 8:46 pm

Basic: Use a 30ohm or greater POTentiometer. Install @10 ohms between gauge and sender, tweak to perfection. POT must be able to handle 10v.!
Extra: I added a 100ohm [two sided 12volt] POT, but only connected the 30 ohm front side between the tank and gauge. Upon final install it was turned to 6-ohms, from there I tweaked it under the dash just a skosh after a fill up, to get the gauge @FULL to sit right on the white line. Since then it's been good with my fill ups, roughly 7-8gals @1/2 tank. And on full it sits right on the 1/1 line.
I've yet to test to E though.... yeah I know :roll:

Thu Dec 17, 2009 10:02 pm

Quote: I've yet to test to E though.... yeah I know

Keep us posted. It can be a long walk that you will think about for a long time. Ask me how I know. I-10 eastbound Tuscon city limits 1978 3:45am.

Tue Dec 22, 2009 5:17 pm

Got a 25ohm rheostat set to about 6.0ohms and it's connected between the sender and VR (the VR then connects to the gas gauge(analog display)). The gauge is almost in the middle of the red zone -- yeay! -- so I'm hoping tomorrow I'll run out of gas on the way home :lol: Then I can zero the gauge to what I want Empty to be then fill her up to see where Full is.

Tue Dec 22, 2009 5:34 pm

You know I have to ask, why risk picking up all sorts of crap from the bottom of the tank and also having the bus die in an inconvenient spot when it only takes 10-15 minutes to drain the tank? set your E mark and dump a gallon back in and look at the gauge, etc., etc.........

Tue Dec 22, 2009 8:27 pm

Quote: You know I have to ask, why risk picking up all sorts of crap from the bottom of the tank and also having the bus die in an inconvenient spot when it only takes 10-15 minutes to drain the tank? set your E mark and dump a gallon back in and look at the gauge, etc., etc.........

BusDaddy - the drain on these is at the bottom you know. They bottom feed trash all the time. That is also why when they run out, they run out.

Tue Dec 22, 2009 9:31 pm

SGKent wrote: Quote: You know I have to ask, why risk picking up all sorts of crap from the bottom of the tank and also having the bus die in an inconvenient spot when it only takes 10-15 minutes to drain the tank? set your E mark and dump a gallon back in and look at the gauge, etc., etc.........

BusDaddy - the drain on these is at the bottom you know. They bottom feed trash all the time. That is also why when they run out, they run out.

Well yeah, but i'd rather see a bunch of floaties in the bottom of a jerry can than in my carb :wink:

Tue Dec 22, 2009 10:48 pm

Vibrator got ya down? Turn that frown...upside down!

Tue Dec 22, 2009 10:54 pm

Air_Cooled_Nut wrote: Got a 25ohm rheostat set to about 6.0ohms and it's connected between the sender and VR (the VR then connects to the gas gauge(analog display)). The gauge is almost in the middle of the red zone -- yeay! -- so I'm hoping tomorrow I'll run out of gas on the way home :lol: Then I can zero the gauge to what I want Empty to be then fill her up to see where Full is.
Your setup sounds a bit different than mine.
The rheostat/POT should sit between either: the VR output and the gauge, or the tank sender and the gauge, to add resistance to the chain of connections. But it sounds like your VR is "touching" your sender via the POT [couldn't that fry the sender? but maybe I am mis-interpreting :) ]
The chain of input/output connections that I have is: ->12V-power-> 10v-VR-> Gauge-> POT@10ohms-> Tank_Sender-> Ground

Wed Dec 23, 2009 9:33 am

busdaddy wrote: You know I have to ask, why risk picking up all sorts of crap from the bottom of the tank and also having the bus die in an inconvenient spot when it only takes 10-15 minutes to drain the tank? set your E mark and dump a gallon back in and look at the gauge, etc., etc.........
Cuz it's the red-neck way to clean out my tank? :lol:

The day I drove her home she ran out of gas. Got a new filter the next day just to be safe (lordy knows when the PO last changed it out). That's what filters are for, right? Plus when I get home after work the outside temp and precipitation is very unfavorable for working under a vehicle. And the Bus doesn't fit past the garage door opening with that Rivi top on it. Also, there's no spigot to make draining easy. I installed new gas lines when I got the Bus so I know this as fact. The nipples under the tank are welded to the tank.

I carry a spare gallon w/me on the luggage rack. I take the "back roads" around town and there are plenty of gas stations about so I don't end up being a hazard to traffic. Worse comes to worse, I have triple A ;)

I'm in no hurry... 8)

Wed Dec 23, 2009 9:41 am

timo78 wrote: Air_Cooled_Nut wrote: Got a 25ohm rheostat set to about 6.0ohms and it's connected between the sender and VR (the VR then connects to the gas gauge(analog display)). The gauge is almost in the middle of the red zone -- yeay! -- so I'm hoping tomorrow I'll run out of gas on the way home :lol: Then I can zero the gauge to what I want Empty to be then fill her up to see where Full is.
Your setup sounds a bit different than mine.
The rheostat/POT should sit between either: the VR output and the gauge, or the tank sender and the gauge, to add resistance to the chain of connections. But it sounds like your VR is "touching" your sender via the POT [couldn't that fry the sender? but maybe I am mis-interpreting :) ]
The chain of input/output connections that I have is: ->12V-power-> 10v-VR-> Gauge-> POT@10ohms-> Tank_Sender-> Ground
See why I ask for details? Always assume the air-cooled nut reading the post is a dummy :shock: :lol: My setup is what I interpreted from what you wrote...your textual diagram now helps.

Placing it where I did did make a difference in the gauge reading (lowered it). I used simple spade connectors so it's easy to swap things around. I can set it up your way, no prob :)