Quote from: apmaman on March 09, 2018, 03:52:26 PM
That was the idea to overcome the sender issues.

Just cant get it to set correctly. Batteries flat now so will look at it next week maybe. One more try then if not it'll be guess work like before!

you tell then adaptor 5? points of fill on the sender unit  you do the same with the gauge then so they can talk then set the needle to the ohms from memory a clever bit of kit just takes time to calibrate. you just need the ohms readings for the sender and gauge in various positions then the unit is used to match them.

Yeah this one as a setting so you can set whatever the sender reading currently is to a defined point.

So i knew i had 5l in. I wanted to save it as tank empty. Saved it. Moved on to 10l in tank. Saved sender reading as quarter... etc etc then i set the gauge needle to each saved point but it wont work out.

Tried cailbrating that way from empty to full.... no joy
Calibrated from full to empty. Again no joy.


How do u get the ohms from the sender? Iv a multi meter but I cant remove it without taking half the car apart.


Last ditched effort before i fling the box in the bin haha!

That is why I could not finish it off as I would have had to strip the bonnet and screen off so left it to buggysteve over the winter.  He had a type 3 gauge and beetle sender.  The ohms resistance to tank contents is not linear and I did not have a spare beetle sender to use on the bench to play with but the beetle is 0 ohms full to 90 ohms empty the T3 was 0 empty and 75 ohms full thinking about it sat here.
I think a bit of trial and error is involved but with parts on the bench it would be simple to check the calibration through out the range.

Cheers Snoopy.

Will give it a bash tomorrow with the ohm inputs rather than the "quick" method. Here's hoping! Even if I get the needle to be on the red at the correct level I'll be happy as thats the most important part.

from memory it was ohm meter on a pin or wire then adjust the empty to full pots to get the relevant ohms reading you had taken off the sender then you did the gauge empty and full ohms then set the needle position on another pot. took me a few times of reading to get to grips with it.

Surely there's no need to dismantle.

Measure the resistance to earth where the adjustment gadget will be and buy a potentiometer of the appropriate range. Use your meter to set the pot for empty and connect the pot between earth and the gadget and adjust the gadget till the gauge reads right. Repeat for the other settings.

So long as sender is good and there is a good earth on it should work with no dismantling

 You need to drain and refill the fuel tank to get it right as you cannot get to move the sender with a wire down the filler. a good bit of kit but setting up is a bit involved. My gauge reads full on the vw sender until I hit 2 gallons left in the tank then it starts moving down and is empty at 3/4 but that is fine as I know.

Quote from: snoopy on March 10, 2018, 08:21:00 AM
You need to drain and refill the fuel tank to get it right as you cannot get to move the sender with a wire down the filler. a good bit of kit but setting up is a bit involved. My gauge reads full on the vw sender until I hit 2 gallons left in the tank then it starts moving down and is empty at 3/4 but that is fine as I know.

Surely draining to the empty point can be done without dismantling from underneath and I know you can refill without dismantling I have seen you do it 

Well been at it again all day today.

No joys. I tried some of the preset settings as well to see if anything worked but no joys on any of them either.

I tried again to get the ohms from the sender with the multi meter -ve in -ve of sender wire. +ve multimeter in sender output that goes to the gauge but I couldn't get a reading no matter what.
Putting the sender back as "stock" works, as in it usually does. Reads empty after using 10l of the 25l capacity, so the sender is ok. I must be measuring it wrong. But thats how I remember doing it, take the sender (variable resistor) out the circuit so that can't interfere and moving the sender should alter the resistance... I duno. Maybe the fumes from all that petrol has gotten to me!!

Giving up on this wee box until I find the enthusiasm (or someone that knows what they are doing!!!!)  to get at it again.

You test the sender omhs from the mounting plate to the feed terminal, the ohm meter needs to read 0 - 100 ohms and for absolute accuracy ( not required for this )you should include the wire to the new box and onto the buggy chassis earth so it covers all parts of the circuit

I have 2 wires from the sender in the tank. One brown negative the other orange grey to the gauge.

The multimeter -ve is poked into the terminal on the wire of the ground wire and +ve on the multimeter goes into the terminal for the orange grey that went to the gauge.

No matter what i fill it doesnt change or make a reading....?

Im using these wires off the sender cause i cant physically get to the sender posts unless i develop octopus arms 

One last ditch attempt today to get some kind of readings out the sender then i have no idea what to do.

Sorry if I am teaching you to suck eggs but

You need the multimeter set to a low range, otherwise it will probably just look like a short.

If the meter is working (crude test check across a spare bulb) and there is still no change them suggests a break in the circuit or a knackered sender. My last sender from GSF only lasted a few years then the resistance coil broke and it was history. Read over part of the range, then stuck on the break

Good luck

Quote from: Doon L001 on March 11, 2018, 01:01:33 PM
Sorry if I am teaching you to suck eggs but

You need the multimeter set to a low range, otherwise it will probably just look like a short.

If the meter is working (crude test check across a spare bulb) and there is still no change them suggests a break in the circuit or a knackered sender. My last sender from GSF only lasted a few years then the resistance coil broke and it was history. Read over part of the range, then stuck on the break

Good luck

Ah no egg sucking here. No worrys about that. I got donated a "fluke" from a chap i use to work with so i knew it was me or the buggy.

I have found the problem though.

After a lot of faffing to spidermanning my arms onto the sender and brimming reads only 16 ohms..., and after draining 3 !! 3 Litres it reads 0.. draining any more just gets an error. So the sender must be maxing out inside the tank from the angle of the tank and the senders position.. Or its f...ered.

As i was draining 5l each time to check i never knew where it was going bad. Since i did 1l at a time i found my problem.

Explains why the tank read empty after about 50 miles too.

Ahh well. Im not taking the front half apart, fook that.

Sounds like the same problem I had when my sender failed. Tank angle also stops full travel on mine

All the best
Dave

the Jas sender failed after 6 months that was from a VW supplier not GSF so it gets brimmed at 150 miles.as like you I cannot be bothered to strip and renew it again.