Late Bay New Fuel Gauge Senders And Their Readings
- Amskeptic
- IAC "Help Desk"
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Late Bay New Fuel Gauge Senders And Their Readings
I have run across many people recently who are not happy with their new fuel gauge senders. A common complaint is that the new sender only displays half full when the tank is actually filled up. Another increasingly common scenario is that the gauge plummets rapidly towards reserve when there is still plenty of gas left in the tank.
SO . . . look at the gauge. It is not linear. From full to half takes only 1/3 the travel. Then, 1/2 to below reserve takes 2/3 the distance.
We know that a full tank should yield a sensor reading of 10 ohms.
An empty tank should yield a reading of 75 ohms.
The gauge needle is linear. A half tank *reading* on the gauge should occur by around 25 ohms, then we have a long trip to empty from there.
It is the SENDER that gives us a progressively faster descent as the fuel level drops.
Here is a factory sender. Ignore the burnt up mess, please. The small end is the full side. Each loop slowly adds resistance, and the heater slowly cools and allows the needle to move lazily towards 1/2. Then the loops get bigger and each loop causes a larger increase in resistance and the gauge moves more quickly towards empty.
You are viewing the "variable resistor" from the "front of the bus" back. The lever/float goes up to the right in this photograph, which is actually to the left when installed in the tank. The short end of the "variable resistor" is toward full.
Does anyone have a new sender sitting around? I was thinking, the above symptoms could occur if:
a) the new sender has a non-progressive "variable resistor"
b) the new sender has a progressive "variable resistor" installed backwards
I'd like to resolve this.
Colin
SO . . . look at the gauge. It is not linear. From full to half takes only 1/3 the travel. Then, 1/2 to below reserve takes 2/3 the distance.
We know that a full tank should yield a sensor reading of 10 ohms.
An empty tank should yield a reading of 75 ohms.
The gauge needle is linear. A half tank *reading* on the gauge should occur by around 25 ohms, then we have a long trip to empty from there.
It is the SENDER that gives us a progressively faster descent as the fuel level drops.
Here is a factory sender. Ignore the burnt up mess, please. The small end is the full side. Each loop slowly adds resistance, and the heater slowly cools and allows the needle to move lazily towards 1/2. Then the loops get bigger and each loop causes a larger increase in resistance and the gauge moves more quickly towards empty.
You are viewing the "variable resistor" from the "front of the bus" back. The lever/float goes up to the right in this photograph, which is actually to the left when installed in the tank. The short end of the "variable resistor" is toward full.
Does anyone have a new sender sitting around? I was thinking, the above symptoms could occur if:
a) the new sender has a non-progressive "variable resistor"
b) the new sender has a progressive "variable resistor" installed backwards
I'd like to resolve this.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
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- IAC Addict!
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Re: Late Bay New Fuel Gauge Senders And Their Readings
This would be great to solve. I am in that group of the tank half full needle while actually full. Does that make me an optimist?
- wcfvw69
- Old School!
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Re: Late Bay New Fuel Gauge Senders And Their Readings
Colin,
PM Gary (aeromech) on The Samba. He has two buddies who are electrical geniuses. One is Telford who participates on The Samba and another is a guy who works with Gary. Telford helped come up with a fix for the tube original senders in bay buses.
PM Gary (aeromech) on The Samba. He has two buddies who are electrical geniuses. One is Telford who participates on The Samba and another is a guy who works with Gary. Telford helped come up with a fix for the tube original senders in bay buses.
1970 Westfalia bus. Stock 1776 dual port type 1 engine. Restored German Solex 34-3. Restored 205Q distributor, restored to factory appearance engine.
- Bleyseng
- IAC Addict!
- Location: Seattle again
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Re: Late Bay New Fuel Gauge Senders And Their Readings
Really? This is a problem? Hmm, I installed a new sender in about 2009 and it reads Full when full and then when it hits Reserve I have about 3 gallons left.
Geoff
77 Sage Green Westy- CS 2.0L-160,000 miles
70 Ghia vert, black, stock 1600SP,- 139,000 miles,
76 914 2.1L-Nepal Orange- 160,000+ miles
http://bleysengaway.blogspot.com/
77 Sage Green Westy- CS 2.0L-160,000 miles
70 Ghia vert, black, stock 1600SP,- 139,000 miles,
76 914 2.1L-Nepal Orange- 160,000+ miles
http://bleysengaway.blogspot.com/
- asiab3
- IAC Addict!
- Location: San Diego, CA
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Re: Late Bay New Fuel Gauge Senders And Their Readings
Yes, this is a problem!
Every (new) sender I’ve seen has a square board with resistor wire wrapped around it- none of them have the original oblong quadrilateral shape like Naranja did.
BigEmma Crew and I half-heartedly bent the arm two years ago to get a more full reading, but it didn’t go far enough. They bent it more last week and I’m waiting to hear if they get an honest “full” reading.
Robbie
Every (new) sender I’ve seen has a square board with resistor wire wrapped around it- none of them have the original oblong quadrilateral shape like Naranja did.
BigEmma Crew and I half-heartedly bent the arm two years ago to get a more full reading, but it didn’t go far enough. They bent it more last week and I’m waiting to hear if they get an honest “full” reading.
Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.
145k miles with me.
322k miles on Earth.
- Amskeptic
- IAC "Help Desk"
- Status: Offline
Re: Late Bay New Fuel Gauge Senders And Their Readings
You clearly are. If you were not, you would have exited the Volkswagen Bus freeway a long time ago.
Me? I'm full of it and yet, I'm half-empty.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
- Amskeptic
- IAC "Help Desk"
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Re: Late Bay New Fuel Gauge Senders And Their Readings
Hah! A hA!. HA!! Really?asiab3 wrote: ↑Tue Jun 12, 2018 7:45 amYes, this is a problem!
Every (new) sender I’ve seen has a square board with resistor wire wrapped around it- none of them have the original oblong quadrilateral shape like Naranja did.
BigEmma Crew and I half-heartedly bent the arm two years ago to get a more full reading, but it didn’t go far enough. They bent it more last week and I’m waiting to hear if they get an honest “full” reading.
Robbie
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
- asiab3
- IAC Addict!
- Location: San Diego, CA
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Re: Late Bay New Fuel Gauge Senders And Their Readings
The grammar and geometry closet of my brain is cringing right now. The senders have “squared off corners.” The boards themselves are rectangular and not perfect squares.
But yes.
Robbie
But yes.
Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.
145k miles with me.
322k miles on Earth.
- Amskeptic
- IAC "Help Desk"
- Status: Offline
Re: Late Bay New Fuel Gauge Senders And Their Readings
Oh Geoff.
This is no time to preen about the good old days of 2009.
It's all gone to hell since then . . .
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
- Amskeptic
- IAC "Help Desk"
- Status: Offline
Re: Late Bay New Fuel Gauge Senders And Their Readings
Nobody here is getting on your case about the word choice.
My ha ha haha hahaaaaaaaaaa is merely an unpleasant gloating at a possible verification of my suppositions.
Colin Hahaaaaha
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles