New gas tank sending unit.

Was the float arm bent so it is facing the correct direction?

I bent it down, towards the lowest part of the tank, towards the front of the car. I think it is hitting bottom or pretty close.

Take it out. Ground the housing to the tank with a wire with some alligator clips on it. Turn on the ignition. Go through the sweep of the sender-- I'll bet when the float is down, the gauge reads full and when up it reads empty.

I think you have to bend the float arm 180* around so that it's correct.

What Stan said but be careful with a possible spark, do cover the float hole with a clean rag to keep fumes away from the float an electrical source.

For future reference, Greg sells pre-modified sending units for the same price just about everyone else sells OEM VW one's.

Be careful, Calamity Bob!

What Stan and Alan said!

Two solutions:

A Porsche sender works well and doesn't bounce around too much. You can fine these (made in china) for about $30. An OEM sender will be about $100.

To be absolutely, positivity sure get a stick. With a pocket knife cut a number of notches in the length about 1" apart. Stick it in the filler and if it's comes out wet you've got gas. Many of the folks here have espoused this method in the past.

Reset the odometer when you fill up. Know what your burn rate is. I get about 200 miles on a 10 gallon tank before I get nervous.

When all else fails fly the numbers

It depends on your gauges.  VDO's standard is 10-180 Ohms, while old VW standard is 73-10 Ohms.  Mixing the senders incorrectly will make it read backwards and also not give an accurate full or empty when bent 180 degrees.  There have also been some oddball (non-VDO) Brazil gauges as well as some oddball China gauges with "custom" Ohms ranges that really don't match either of these but can be controlled with the above by setting the stops at the appropriate spot.

Jim - do you mean the tube one used on late VW Karmann Ghias and the 914?

Tanks Inc. also makes custom length  float less tube senders also.  I use them in our race cars with custom fuel cells, and in the new coupe.  

Although they don't have an early VW spec, it is the same as early Mopar, and they stock a "standard" VDO spec also.  You just give them a length and they cut and cap the sender and send it to you.

I'm using a product from Centroid in Florida, no moving parts,can be calibrated to our non linear VDO guages, accurate to empty.  Ask for Joel, mention my name , I did the calibration and he programed the sender.

@R Thorpe  great link and I've bookmarked it.  Something like that will be handy when a client requests custom/odd gauges.  Thanks

I have no connection other than being a satisfied customer, found them years ago when I put a Fuel Safe cell in my 911. Cheers

Richard

Thanks R Thorpe

I bent my arm 180 degrees and now I am in the hospital, and the thing still reads wrong.

The thing I found about the stock arm is that the tank is roughly 7 1/2 inches deep where the sender is and the sender arm is much longer so it sits on the bottom of the tank for part of its swing.  When I drove away from Greg at VM the last things he said was don't trust the fuel gauge under 1/4 tank and the turn indicators don't cancel I did a lot of testing of the Centroid sender. I drained the tank till the guage read empty and looked inside with one of those scopes from Amazon.  The tank hadbetween 1/4 and1/2 gallon left below the sender around the outlet. I put 2 gallons back in and the VDO guage read 1/4 tank, I added another 2 1/2 gallons, 1/2 full, added 2 1/2 more guage read 3/4 and 10 gallons full. Now I know if the guage reads empty I've got about 5 miles left at least.

Being old school OCD, my gas gauge drove me nuts for the first year.  If I adjusted it for the proper “full” reading then it was way off at “empty”.  If I then re-adjusted it for “empty” it was way off at full (not to mention that it used to have that typical, half-gauge needle swing as gas sloshes around in the tank).  

Finally, I got tired of messing with it and set it so that when the needle hits empty and is still moving slightly off the bottom on a hard turn, I still have maybe a gallon of gas left down in there and can creep to the next gas station.  

I really don’t care about any reading north of 1/2 tank (and why should I? ) and it seems consistently accurate below 1/8 tank, so I live with it as part of an eccentric automobile. AND I have never run out of gas on the road!  That says something!

Yeah, you've got about five miles left if you don't accelerate, brake, or turn. There is absolutely no baffling in a VW tank.

What I do in the Spyder is get gas when it reads 1/4. Simple and effective. I have Speedhut gauges which I programmed to my sender at full and empty, so full is full, and empty is empty.

@WOLFGANG posted:

Jim - do you mean the tube one used on late VW Karmann Ghias and the 914?

I do! Followed some advise from the knowledgeable folks on this site. The cheap one works about 9 months.

I've said that 3 times before, sure that last one is the charm. At this time in my life she should hold up 'til "death do us part". I really don't want to buy this house again.