Fuel gauge

[Merian]

doesn't the Voltage Stabilizer do things besides run the fuel gauge?

BTW, when full mine goes past 1/2 - it consistently goes to about 7/8 or so - still an annoyance

[dobryan]

And mine is the opposite. When full it is pegged, and after 60 miles it is still at full but not pegged, at 1/2 tank mark it takes 10 gallons to fill it. I use the trip odometer more than the gas gauge these days....
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Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD

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[j_dirge]

[jerryherb]

I know its been a while since the last response. My fuel gauge is NOT working at all. tested the gauge itself (with a 9v batt) and it moves. foil is surprisingly in amazing shape for a late 85. all continuity there. i assume that the voltage stabilizer works as the coolant temp gauge also runs on 10V and works fine. im not currently anywhere near the vehicle, but looked at the wiring diagram (92.62). it shows that the sender is supposed to ground by the fuel pump (?) i dont have any other ground wires by the fuel pump other than the fuel pump itself (recently replaced so i know whats there). is there any other place it would ground? is there a way to check the wiring all the way up to the sender without dropping the tank? thanks!

[AndyBees]

Just to be sure, what year model is your Vanagon?

I've never seen no other ground wire at the Fuel Pump besides the one for the pump itself...
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'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[jerryherb]

[AndyBees]

Thanks.

I installed an ALH TDI in my 84 Vanagon which had the Digijet fueling system. So, as an aid, I copied all of the appropriate wiring schematics of both the Jetta and Van to do extensive research and note taking.

Although my Van is an 84 the wiring schematic is practically the same as the 85 model. My schematic shows what you referenced on page 97.60 to be on page 97.56.

Anyway, they both reflect the ground point for the fuel gauge sending unit to be at 15. 15 is supposed to be at or near the fuel pump as you stated.

Well, I do believe they screwed up because there is no such ground wire near the fuel pump.

I did replace the connector for the fuel sending unit to the connector from the Jetta fuel tank because I used the Jetta fuel sending unit in the Vanagon Tank. However, the Van wiring was not used because in my case the two circuits go directly to the Jetta Cluster, which I did install.

So, considering the fuel level sensor is on the left side of the fuel tank and the fuel pump is on the right side of the vehicle, I seriously doubt that they extended a ground wire all the way over to an area near the fuel pump. I just do not remember that being the case... I've had my fuel tank off and on several times. Thus, I'm think both the ground and positive circuit go back toward the dash of the Vanagon ... most likely the ground is going to be either under the dash or some where on the body near the left side of the fuel tank.... makes more sense to me!

Sorry for such a long explanation.
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'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[crazyvwvanman]

Unfortunately on many vans VW chose to put the ground for the fuel tank sender above the tank itself. The brown ground wire is screwed into a frame rail where the tank hides it.


There is some risk but you could lower the tank enough to reach the sender wiring plug. Then pull the wires out enough to where you can work on them. Cut the brown and extend it with more wire so you can screw it to body metal where it can be reached.


Mark

[AndyBees]

Yep, that was what I was thinking ... the ground has to be near the area of the tank.

There is quite a bit of "slack" in the two wires. But, without removing the cross-over vent pipe, it will be very difficult to lower the tank enough to access the connector at the sending unit. It's worth a try, but keep in mind, if one or both of the fittings of the cross-over vent pipe pops out of their grommet, they will need to be put back... other gasoline will come out when full and/or sloshing.
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'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[jerryherb]

thanks. i'll give it a look with an inspection camera before i stick my fat hands in there.

[toomanyveedubs]

I can second the suggestion to check/replace the voltage regulator on the back of the cluster first. 99% that's your problem and nothing inside the tank.

[jerryherb]

[toomanyveedubs]

they don't necessarily fail "dead", they can in many cases not output the right amount (sufficient) of voltage and cause the gauge to misread low.

[Merian]

anybody have a quick way to check the VR they can post?
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[toomanyveedubs]

pull the wire to the fuel level sensor and short the two connections together. If the fuel gauge goes full tank its good. if it only goes part way up its shot. easy on a syncro, a bit harder to reach on 2wd