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Fri Jun 08, 2012 8:43 am

So I installed a new fuel gauge sender about a year ago and ever since then the needle would bob up and down and work sometimes but other times wouldn't work at all. I also noticed that when I filled up the tank to full I could distinctly smell gas quite strong. So I decided to cut an access hole (I did it really carefully and it looks quite nice). I get in there and see that the sender is loose on the tank! That explains the gas smell when full. Then I pull out the sender and take it apart and this is what I see:

That would explain the gauge bobbing up and down and working sometimes but not others. How do you think this happened?

Also when I ground the wire going to the gauge the needle only goes up to about 3/4 a tank and not to the 1/1 mark. Could this be attributed to resistance in the old wire? Should I run a new wire when I get a new sender? Or should I replace the vibrator with the solid state fix seen here on the samba?

Fri Jun 08, 2012 8:47 am

tootype2crazy wrote: Also when I ground the wire going to the gauge the needle only goes up to about 3/4 a tank and not to the 1/1 mark. Could this be attributed to resistance in the old wire? Should I run a new wire when I get a new sender? Or should I replace the vibrator with the solid state fix seen here on the samba?
How about if you ground right at the back of the gauge?, if it reads the same the vibrator is suspect.

Likely also the cause of the F'd up sender, although most appear more burnt than that.

Fri Jun 08, 2012 8:51 am

Good to know, I wish I had done the solid state fix on the vibrator before I spent $60 on this sender only to have it crap out. I thought about it and didn't do it. Oh well. I'll go ground out the gauge now.

Fri Jun 08, 2012 9:00 am

Ok I grounded out the wire going into the gauge right above the vibrator and the gauge went to 1/1, just past actually.

Fri Jun 08, 2012 9:12 am

OK, then clean up the big connector where the main harness comes up into the dash (on steering column brace on a 79 IIRC) and confirm you are grounding to a good ground at the back, usually the wire doesn't break down but a connection does.

Fri Jun 08, 2012 9:15 am

Would the resistance in a connector/wiring burn up my sender like this busdaddy?

Fri Jun 08, 2012 9:24 am

No, usually the result of stuck points in the vibrator so the system got full battery voltage.

Fri Jun 08, 2012 9:24 am

I suspect you are just seeing the results of junk low quality materials and workmanship. For a decade it seems senders have not read correctly from the get go and needed to be tweaked a bit to get them to read even close to what they should. I have heard some of the newer ones are better but haven't tried one yet. Thinking I might just buy some nichrome wire and try rewinding an old one.

Fri Jun 08, 2012 9:35 am

How was your sender loose on the tank?

Fri Jun 08, 2012 9:36 am

Well I think I will go ahead and do the vibrator fix, that way if the new sender I get is a little sketchy I'll know it wasn't it.

Fri Jun 08, 2012 9:40 am

AB westy nut wrote: How was your sender loose on the tank?

Not sure how it got that way, I remember it being really hard to put on. I don't think I greased the seal last time, maybe the seal was gripping the metal and it worked loose over time.

Fri Jun 08, 2012 9:46 am

Yeah I found mine impossible to get on so I ended up sourcing a flat profile nitrile gasket. I was still a snug fit but it worked perfectly.

Fri Jun 08, 2012 9:55 am

Just now I put the broken one back on by greasing it with my sunroof lube. It is called superlube and is hard to find, I think you can get it on amazon. It is non-reactive so it won't hurt the rubber or the gas if it gets in there. I placed the sender on and since i cut an access hole, I used a big pry bar with lots of leverage from the access hole and it seated quite easily.

Fri Jun 08, 2012 11:33 am

Ok I cleaned and greased every connection with dielectric grease. When I ground the gauge out in the back by the sender it will indeed go to the 1/1 mark.

After doing it a hundred times I noticed that when I first grounded it, the needle will twitch a few times before rising to the full mark. Then once it is at the full mark if I hold it there it will slowly descend until it shows empty. Actually this is exactly what it did with the sender in there too. So either the vibrator is bad or the gauge itself.

Fri Jun 08, 2012 11:51 am

The bus depot sender I bought last year was $59.XX. Airhead parts has a non-oem repop for $38.95.

http://www.airheadparts.com/vintage-vw-parts/fuel-...11919051-a

Given the shoddy nature of OEM VDO products lately would it be a huge mistake to go with the repop or not?

Fri Jun 08, 2012 1:05 pm

Any thoughts on the sender before I drop the bills?

Fri Jun 08, 2012 4:41 pm

tootype2crazy wrote: Any thoughts on the sender before I drop the bills?

As I said I have heard that some of the more recently made senders are better than the ones produced a few years back. I think my source was referring to VDO but am not sure. No experience with very recently manufactured VDO senders myself.

Fri Jun 08, 2012 4:52 pm

So I got the vibrator off here it is on the inside:

The heating wire wraped around looks kinda wonky. There is a little strand that is crossing the gap which you can barely see in the picture. I don't think it is supposed to based on this site:

http://www.nls.net/mp/volks/htm/fuel_ga.htm

That site is cool, this is the picture I was referring to

I tested the vibrator by hooking it up to a test light and it doesn't work. The heating wire doesn't get hot at all. I just order the stuff to do the solid state fix as seen here:

http://www.thesamba.com/vw/forum/viewtopic.php?t=381486&highlight=vibrator

Fri Jun 08, 2012 4:58 pm

i spent a few weeks trying to source a VDO sensor. even a made in Czek on would have done. could not find it, all the usual places are out of stock and rumor is no more VDO ones coming. i bit it and went with the chinese unit.

o well. if it craps i plan to rewire the old VDO unit and go with that.

i guess what im saying is that you might as well buy whatever unit you can get since they are all the chinese ones. (you could try and hunt for a mexican one)

Fri Jun 08, 2012 5:03 pm

rustbus wrote: i spent a few weeks trying to source a VDO sensor. even a made in Czek on would have done. could not find it, all the usual places are out of stock and rumor is no more VDO ones coming. i bit it and went with the chinese unit.

o well. if it craps i plan to rewire the old VDO unit and go with that.

i guess what im saying is that you might as well buy whatever unit you can get since they are all the chinese ones. (you could try and hunt for a mexican one)

Wonder what is available from Brazil? Really need a good Brazilian contact.