Mechanics

FUEL GAUGE WORKS SPORADICALLY

1970 Volkswagen Beetle

Electrical problem
1970 Volkswagen Beetle 4 cyl Two Wheel Drive Manual 99999+ miles

I have owned this bug for 4 years, and the fuel gauge has worked for only a very short period of time when I first had it. I recently replaced the Speedo/Odometer assembly (with a used part) and the fuel gauge worked again for a short period of time. I replaced the wire from the fuel tank to the gauge, as well as the vibrator (new part), and it now works on and off; usually when in warm weather - in the morning, no gauge, but in the afternoon, it works sometimes.
I assume that it is the fuel sender at this point, but was wondering if the issue of warm/cold behavior indicated anything else - the temperature refers to environment temperature, not necessarily whether the engine is warmed up or not.
Avatar
Cptspith
July 21, 2010.



Hi cptspith,

Thank you for the donation.

Symptoms indicates the problem is more likey to be from the gauge side. It could be a loose or contaminated contact. The gauge worked after you replaced the meters. When removing and installing the meter cluster, the connectors were worked on and that could have temporarily improved the contacts thsu you were able to have the gauge working for a few days.

If you suspect the sending unit to be the cause, when it does not work, ground the wire from gauge to sending unit and if the needle goes up to maximum, then the sending unit is the cause. Do not keep the wire grounded longer than necessary.

KHLow2008
Jul 21, 2010.
Not to sound like an idiot, but to ground the wire, can I simply disconnect the end from the sender contact, and touch it to the metal body, or is it more involved than that? Thanks again for your help!

Tiny
Cptspith
Jul 21, 2010.
Yes, disconnecting and grounding is the correct way.

Alternatively you can use a probe to push into the connector and ground it, does not matter which way it is done.

KHLow2008
Jul 21, 2010.
I had similar symptoms in my 68 beetle. I traced the problem to a loose fitting at the back of the speedo housing. The connector was tight electrically, but occasionally shifted so as to ground itself against the case. Fixed (at least for now) by careful re-location.

Tiny
Milroyc
Jul 31, 2010.
That is the problem with terminal connections when they get old. Sometimes contacts becomes loose and vibrations would cause them to have intermittent contacts.

Wiggling test for connectors are required when checking intermittent or failed continuity.

KHLow2008
Aug 1, 2010.