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omegared11211
Samba Member
Joined: November 22, 2014
Posts: 17
Location: Arizona
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 Posted: Tue Jan 20, 2015 8:23 pm Post subject: Gas Guage has me stumped |
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68 Bug. The Gas Gauge never worked correctly since I bought the car. Gauge would give erratic levels no matter how much gas was in the tank. Bought a new sending unit. Now the gauge registers empty when tank is full. I have read some of the posts on here regarding gas gauge/sending unit/vibrator. When I remove the wire from the sending unit and ground it, the gauge goes to full then back to empty when ungrounded (which if I have read correct it would mean the sending unit was bad). Thought the new sending unit was bad, put the old one back in with the same result.
I have redone all the connectors/wiring for the sending unit, vibrator. Checked and cleaned all grounds/screws/nuts. Double checked all the wiring and everything is plugged in where it belongs. Nothing has made a difference. I can only assume the vibrator, gauge or both are bad but not sure. Hoping someone can give me a clue or direction to go.
Oh on a side note, the odometer does not work (read on here how to fix that) so having the gas gauge working will help monitor fuel levels will help especially since the bug will be going to my daughter to drive. |
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MacLeod Willy
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Joined: February 18, 2014
Posts: 933
Location: Ontario Canada
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| Posted: Tue Jan 20, 2015 8:38 pm Post subject: |
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Sounds like a poor ground on the sending unit. That's the easiest to check at least.
Then pull the sender and hook an ohmmeter to it as you move the gauge and watch for fluctuations |
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busdaddy
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Joined: February 12, 2004
Posts: 53188
Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Tue Jan 20, 2015 8:59 pm Post subject: Re: Gas Guage has me stumped |
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| omegared11211 wrote: |
| Bought a new sending unit......... |
Sure the float hasn't sunk?, apparently they don't put corn squeezin's in the gas in China.
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MacLeod Willy
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Joined: February 18, 2014
Posts: 933
Location: Ontario Canada
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Aussiebug
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Joined: June 03, 2002
Posts: 2162
Location: Adelaide Australia
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| Posted: Tue Jan 20, 2015 10:00 pm Post subject: |
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That reference is for the later fuel guages 72+ which have two connectors, ground and active.
Omegared has a 68 which has only one wire on the sender. The grounding happens through one of the 5 bolts attaching it to the tank, and then relies on the tank being well grounded to the body via the four clamps which hold it down.
Test - remove the single wire from the sender and ground it to the clean chassis metal. the gauge should read full with the ignition on. If it does not, the gauge or sending wire is faulty.
If it does read full when wire is grounded, then the wiring and gauge are good, but the sender is not properly grounded to the tank or the tank is not properly grounded to the chassis, (or the sender is toast, but since you replaced that, the other two possibilities are the most likely).
Re the odo not working. If the speedo is still working, then the cable is fine, and it's probably the drive cog inside the speedo which has failed. Unusual in a 68 which has a brass drive gear, but common enough in 73+ cars which have a plastic drive gear. The only way you can check, is to remove the whole speedo unit and take it apart - for that you have to GENTLY pry the chome bezel off the face (working around and around so you only bend the lip JUST far enough to get it off) so you can remove the innards and check the drive mechanism.
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Rob
Rob and Dave's aircooled VW pages
Repairs and maintenance for the home mechanic
http://www.vw-resource.com |
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MacLeod Willy
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Joined: February 18, 2014
Posts: 933
Location: Ontario Canada
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| Posted: Wed Jan 21, 2015 7:23 am Post subject: |
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| Aussiebug wrote: |
That reference is for the later fuel guages 72+ which have two connectors, ground and active.
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Regardless if its one wire or two still the same procedure for testing the system. You need a ground path to the sending unit.
I said it was a good article to read |
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omegared11211
Samba Member
Joined: November 22, 2014
Posts: 17
Location: Arizona
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| Posted: Wed Jan 21, 2015 5:45 pm Post subject: |
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Thanks for all the help. I have seen the how to on testing the vibrator/sending unit/gauge. I haven't had the time to pull everything out and test. I have also read up on taking the speedo apart to check the gear for the odometer. The MPH works fine just not the odometer. Wasn't a big thing until the gas gauge quit. I did notice on the new sending unit instead of metal washers there were plastic ones. I will swap those first and see what happens. I did clean the spots where the tank bolts to the body with no luck. Hopefully this weekend will allow me the time to figure it out.
Thanks again for all the replies and help.
Joe
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South East Arizona 1968 Beetle |
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omegared11211
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Joined: November 22, 2014
Posts: 17
Location: Arizona
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| Posted: Wed Jan 21, 2015 6:35 pm Post subject: Update |
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Well I looked at all the screws for the sending unit. I put a metal washer on one of them and the gauge started working!!!!!
Thank you for all the help!!!
Now onto the odometer and other quirks!!!
Thanks again!!!!!
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South East Arizona 1968 Beetle |
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Aussiebug
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Joined: June 03, 2002
Posts: 2162
Location: Adelaide Australia
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| Posted: Wed Jan 21, 2015 11:54 pm Post subject: Re: Update |
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| omegared11211 wrote: |
Well I looked at all the screws for the sending unit. I put a metal washer on one of them and the gauge started working!!!!!
Thank you for all the help!!!
Now onto the odometer and other quirks!!!
Thanks again!!!!! |
Thanks for letting us know. With bugs, the general rule is "always look for the simple fix first", you'll often find the problem before going to the complex fix!
Macleod Willy - I wasn't criticizing you above - just making a statement of fact. The differences in fuel gauge senders might confuse folks who weren't aware of the difference. Yes - that article is worth reading.
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Rob
Rob and Dave's aircooled VW pages
Repairs and maintenance for the home mechanic
http://www.vw-resource.com |
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MacLeod Willy
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Joined: February 18, 2014
Posts: 933
Location: Ontario Canada
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| Posted: Thu Jan 22, 2015 6:46 am Post subject: |
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Nice to hear a final outcome, lots of times everyone is left hanging never knowing whether they got the problems fixed, thanks for posting.
Hey Aussie, No worries  |
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usroute66
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Joined: March 12, 2012
Posts: 74
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| Posted: Sat Sep 23, 2017 11:32 am Post subject: Re: Gas Guage has me stumped |
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Know this thread focuses on Bugs, but these fuel guage fixes also worked on my 69KG. It's been a good while since there have been any postings to this thread but I wanted to thank all, especially:
1) clues on checking the guage by grounding the sending unit wire connection (needle pegged full, then pegged empty when the ground was removed), that proved the guage was operational,
2) putting a metal washer, instead of a plastic one, on one of the screws holding the sending unit in. After replacing one of the plastic washers with a metal one, the guage works perfectly. Note: I had already put a new sending unit in and the reading appears to be very accurate.
Thanks again. |
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