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MrWhoopee
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Joined: October 24, 2005
Posts: 177
Location: Shingletown, CA
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 Posted: Mon May 17, 2021 1:21 pm Post subject: The Fuel Gauge Saga |
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There doesn't seem to be a sub-forum for general electrical questions, so I guess this goes here. It's in my '63 DC, but that's not particularly relevant. When it got my truck (in '90) it had VDO black-face gauges for oil temp and pressure along with the stock gas gauge. I've never liked the black gauges, so I replace all three with VDO Cockpit Royale white-face gauges. Of course, the gas gauge never worked properly with the stock sending unit, but I lived with it.
Recently I got interested in dealing with it when I discovered that I had a VDO universal sending unit with the right resistance range (10-180 ohms). I'd had it since '76 when a friend totaled his bug, but completely forgot about it when installing the gauges. For reasons I still don't understand, the sending unit resistance was the opposite of the gauge (gauge read Full when empty, empty when full). I was able to reverse the float on the sender so now the gauge reads correctly. My problem is that the gauge does not come up off the E until the tank is about 1/2 full. I've checked the signal from the sender and it is reading 90 ohms (1/2 full) but the gauge says E. It will respond above this level, and will read full when the tank is full. Do I buy a new gauge?
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Craig ('51 WASP)
Rosie ('63 Double Cab) |
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PeteSC
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Joined: January 26, 2011
Posts: 881
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| Posted: Mon May 17, 2021 1:52 pm Post subject: Re: The Fuel Gauge Saga |
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I don't have the exact numbers, but I think the early VW fuel gauges are calibrated to read around 80 ohms empty, and around 5 ohms full.
If your using a sender that has a 10-180 ohm range then I guess your fuel gauge is reading empty until the float gets to the closer to that 80 ohm range, which in your case means about the 1/2 tank you're seeing.
VDO does make new (Brazil made) 0-90 ohm senders if you want to keep the stock gauge. I've had great luck with one for years now in my Ghia. It's pretty darn close to accurate throughout the gauge range too. Jegs and Summit used to carry them...I think the 190mm works for a bus tank. Or you can find an aftermarket gauge that has a range of 0-180 ohms and keep your existing sender. |
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MrWhoopee
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Joined: October 24, 2005
Posts: 177
Location: Shingletown, CA
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| Posted: Mon May 17, 2021 2:28 pm Post subject: Re: The Fuel Gauge Saga |
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| PeteSC wrote: |
I don't have the exact numbers, but I think the early VW fuel gauges are calibrated to read around 80 ohms empty, and around 5 ohms full.
If your using a sender that has a 10-180 ohm range then I guess your fuel gauge is reading empty until the float gets to the closer to that 80 ohm range, which in your case means about the 1/2 tank you're seeing.
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Thanks for the response.
The Royale fuel gauge is designed for 10-180 ohms, the sending unit is the same. You are correct that the stock VW sending unit is 0-80. I just tested the gauge with the stock sending unit, it reads much closer to correct, though still not right. I also tested a black face (10-180) gauge with the universal (10-180) sending unit. It reads correctly.
I just ordered a new gauge.
I'm not happy about it.
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Rosie ('63 Double Cab) |
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Culito
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Joined: December 07, 2006
Posts: 5866
Location: Columbia Missourah
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| Posted: Mon May 17, 2021 3:47 pm Post subject: Re: The Fuel Gauge Saga |
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Thread hijack!
My fuel gauge never worked - it just reads close to empty and seems to get hot. New sender, new gauge.
Checked the ground to the sender body and it seems to be fine.
Check the gauge by grounding the wire that hooks to the sender at the tank and it reads full, which seems to be correct.
All I can guess is a bad or stuck sender?
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Copyright CJ Industries, Inc.
'64 standard w/2.0L type 4
'62 bug
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busdaddy
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Joined: February 12, 2004
Posts: 51145
Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Mon May 17, 2021 3:49 pm Post subject: Re: The Fuel Gauge Saga |
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| Culito wrote: |
| New sender......... |
Did you remove the shipping pin?
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Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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Слава Україні! |
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Culito
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Joined: December 07, 2006
Posts: 5866
Location: Columbia Missourah
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| Posted: Mon May 17, 2021 6:02 pm Post subject: Re: The Fuel Gauge Saga |
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| busdaddy wrote: |
| Culito wrote: |
| New sender......... |
Did you remove the shipping pin? |
Yep, the float was moving normally when installed.
_________________
Copyright CJ Industries, Inc.
'64 standard w/2.0L type 4
'62 bug
| johnnypan wrote: |
| ...dont pay no attention to Culito,he's a cornhole.. |
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busdaddy
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Joined: February 12, 2004
Posts: 51145
Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Mon May 17, 2021 6:08 pm Post subject: Re: The Fuel Gauge Saga |
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| Culito wrote: |
| busdaddy wrote: |
| Culito wrote: |
| New sender......... |
Did you remove the shipping pin? |
Yep, the float was moving normally when installed. |
Where did you get it?
| fes wrote: |
This was my brand new out the box unit i got from CIP |
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Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
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BonTonRoulet
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Joined: September 29, 2020
Posts: 363
Location: Mississippi
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| Posted: Mon May 17, 2021 6:11 pm Post subject: Re: The Fuel Gauge Saga |
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......so you say you acquired a new "universal" fuel gauge sending unit from a buddy that totaled his bug in 1976, it only starts to indicate you have any fuel in the tank when the tank is half full yet shows full when the tank is full......
I'll ask the obvious: Is the fuel gauge sending unit the same length (think depth from top of tank) in a bug as it is in a bus? I don't think they are the same, but it would make sense they aren't (the bug sending unit being shorter) with what your symptoms are? |
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MrWhoopee
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Joined: October 24, 2005
Posts: 177
Location: Shingletown, CA
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| Posted: Mon May 17, 2021 6:45 pm Post subject: Re: The Fuel Gauge Saga |
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| BonTonRoulet wrote: |
I'll ask the obvious: Is the fuel gauge sending unit the same length (think depth from top of tank) in a bug as it is in a bus? I don't think they are the same, but it would make sense they aren't (the bug sending unit being shorter) with what your symptoms are? |
Being that it is a universal sending unit, it is adjustable in length. I adjusted the length and float position per VDO instructions.
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Okie Adam
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| Posted: Tue May 18, 2021 7:29 am Post subject: Re: The Fuel Gauge Saga |
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| busdaddy wrote: |
| Culito wrote: |
| busdaddy wrote: |
| Culito wrote: |
| New sender......... |
Did you remove the shipping pin? |
Yep, the float was moving normally when installed. |
Where did you get it?
| fes wrote: |
This was my brand new out the box unit i got from CIP |
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I've had this exact same issue! The float made it audible slide back and forth so I dropped it in with confidence. Gauge didn't read but it did if I grounded the wire at any point in between the tank and gauge. Motor and tank back out only to find a broken wire.
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Last edited by Okie Adam on Tue May 18, 2021 8:05 am; edited 1 time in total |
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Culito
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Joined: December 07, 2006
Posts: 5866
Location: Columbia Missourah
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| Posted: Tue May 18, 2021 7:53 am Post subject: Re: The Fuel Gauge Saga |
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^^ This is entirely possible in my case.
_________________
Copyright CJ Industries, Inc.
'64 standard w/2.0L type 4
'62 bug
| johnnypan wrote: |
| ...dont pay no attention to Culito,he's a cornhole.. |
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busdaddy
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Location: Surrey B.C. Canada, but thinking of Ukraine
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MrWhoopee
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Joined: October 24, 2005
Posts: 177
Location: Shingletown, CA
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| Posted: Sat May 22, 2021 12:04 pm Post subject: Problem Solved |
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A new gauge solved the problem, it now reads correctly.
I'd like to give a shout out to cip1.com. They had, by far, the best price. Including shipping it was still $10 less than the price of gauge alone from other sources. They also had it in stock when the others didn't and shipped promptly. They'll be my first choice in the future.
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