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dobryan
Samba Member
Joined: March 24, 2006
Posts: 16496
Location: Brookeville, MD
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 Posted: Thu Feb 02, 2023 8:58 am Post subject: Re: Syncro Fuel gauge inaccuracy (how to ground the sending unit) |
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FWIW if you replaced the fuel level sensor and did not check its range of motion it very well could not be sweeping from full to empty within the syncro tank. While I had the tank out on the '87 and replaced the sensor I verified that the float was not adjusted properly (it was a JP part I believe). I had to bend the arm several tries before it was operating from the bottom of the tank to the top. YMMV.
AND the connection from the 'plate' to the neg side of the terminal on the unit did not have continuity right out of the box. A separate neg connection is needed for mine.
Pretty poor QC unfortunately.
(I did verify that the resistance reading from full to empty was correct so they got something right.)
_________________
Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD
"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson
MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646
Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371
The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794 |
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9600
Location: Western WA
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| Posted: Thu Feb 02, 2023 9:15 am Post subject: Re: Syncro Fuel gauge inaccuracy (how to ground the sending unit) |
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| cmayna wrote: |
| Great thread. My fuel gauge shows 3/4 full when filled up. Have been wanting to rip into this issue but had no idea of where to begin. Will check the grounding points of the sending unit. Will reply back soon. Thanks. |
An off-topic reply, buried deep in a Syncro thread, the 2wd version could fall on a lotta deaf ears. But Kamz will see it! 
cmayna if you find a good way I bet 2wd owners would appreciate a specific thread titled "2wd Fuel gauge etc".
| dobryan wrote: |
| AND the connection from the 'plate' to the neg side of the terminal on the unit did not have continuity right out of the box. |
The neg terminal is spot-welded to the plate.
Can't get much better continuity than that.
If the spotweld was faulty/broken, the terminal would be loose & wiggly. ??
In any case, a proper ground wire ensures ground for the future when the steel terminal corrodes the connection (10, 20 years from now).
_________________
'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb |
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dobryan
Samba Member
Joined: March 24, 2006
Posts: 16496
Location: Brookeville, MD
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| Posted: Thu Feb 02, 2023 9:32 am Post subject: Re: Syncro Fuel gauge inaccuracy (how to ground the sending unit) |
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| Sodo wrote: |
| dobryan wrote: |
| AND the connection from the 'plate' to the neg side of the terminal on the unit did not have continuity right out of the box. |
The neg terminal is spot-welded to the plate.
Can't get much better continuity than that.
If the spotweld was faulty/broken, the terminal would be loose & wiggly. ??
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Unfortunately not always so. Yes the neg terminal is intended to be spot welded. But the one on mine has no continuity. It appears rock solid but if you are very precise you can just move it about 0.001" off and on the plate, the weld did not take. The terminal itself is rock solid. The neg part that is spot welded to the plate is not really part of the terminal attachment support apparently.
_________________
Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD
"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson
MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646
Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371
The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794 |
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9600
Location: Western WA
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| Posted: Thu Feb 02, 2023 9:56 am Post subject: Re: Syncro Fuel gauge inaccuracy (how to ground the sending unit) |
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| dobryan wrote: |
| Sodo wrote: |
The neg terminal is spot-welded to the plate.
Can't get much better continuity than that.
If the spotweld was faulty/broken, the terminal would be loose & wiggly. ??
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The terminal itself is rock solid. The neg part that is spot welded to the plate is not really part of the terminal attachment support apparently.
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Strutting around like an upstanding ground path!
Too many grounds cause trouble by "assumption" especially if they're 40 years old.
Ground faults should never be offered anonymity.
I'd expose the fooker especially 'cuz it's new.
(If that was mine) I'd bend that un-adhered tab up off the plate.
_________________
'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb |
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dobryan
Samba Member
Joined: March 24, 2006
Posts: 16496
Location: Brookeville, MD
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Pchill2
Samba Member
Joined: November 19, 2021
Posts: 405
Location: Georgia
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| Posted: Fri Feb 03, 2023 2:13 pm Post subject: Re: Syncro Fuel gauge inaccuracy (how to ground the sending unit) |
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| dobryan wrote: |
| Sodo wrote: |
| dobryan wrote: |
| AND the connection from the 'plate' to the neg side of the terminal on the unit did not have continuity right out of the box. |
The neg terminal is spot-welded to the plate.
Can't get much better continuity than that.
If the spotweld was faulty/broken, the terminal would be loose & wiggly. ??
|
Unfortunately not always so. Yes the neg terminal is intended to be spot welded. But the one on mine has no continuity. It appears rock solid but if you are very precise you can just move it about 0.001" off and on the plate, the weld did not take. The terminal itself is rock solid. The neg part that is spot welded to the plate is not really part of the terminal attachment support apparently.
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Same issue with my brand new classic line. I put a weld bead on it and then moved on the calibrating the arm.
Classic Line will likely need an additional 15 or more degrees of bend in the arm to get the full sweep of the gauge.
I mentioned the ground tab issue in my thread but I thought it might have just been a one off defect.
When troubleshooting OE parts, Sodo’s method is spot on.
When troubleshooting classic line parts, you’ll likely need to weld the tab AND bend the float arm downwards to get the full gauge sweep.
_________________
87 Syncro Westy
Honda K24 swap |
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