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What is strange is that when the gauge was just above empty I filled the tank and could only put 11 gallons in. The gauge showed full after the fill up. This is a new VDO gauge, part number 301 040 003. I can't find a single result on google with this part number. You know something is wack when google only has a few results, and they are in chinese.

I've read quite a few posts about bad grounds causing the fuel gauge to go to empty. I don't think that is the problem here, because right now I can measure the signal to ground at the gauge, and it is good (33.5 Ohms right now, guage reads just under 1/2). I think I have a 60-ohm gauge because then 33 ohms would be just about half a tank, and an empty tank at 60 ohms would mean there should be 6.666 gallons left.

Underneath the part number is "60/90 - 0.5 OHM". Does anyone know how to change the gauge to 90 ohm?

It isn’t broke

Welcome to the fun of trying to interpret the alternative language translations the manuals provide.

As is mentioned on page 26 of the Operators manual, R = Reserve, i.e. approximately 20 liters (~ 5 gallons) still contained. If you ever remove the fuel tank sending unit you will find it does not extend to the bottom of the fuel tank, so when the sending unit sees the tank as empty you are not out of fuel. This was a common practice in the era these trucks were built in providing the inattentive operator with a few gallons after the gauge has bottomed out.

Well dang it! I guess that makes sense then. I suppose the solution is either deal with it, or get a longer fuel sender? Can't say I haven't forgotten to check the gauge a few times myself, though. Thanks for the proper direction.

Ya, I have been "close to empty" a few times, then I fill up only to add 30l or so. Confuses the hell out of me.


Sent from my Mobile

The VDO part number on the gauge is not the same as their marketing/product number which is why you can't find a reference to it. The VDO gauge most likely came from Swiss Army Vehicles under their part number SAV1400. The gauge is not an exact functional match for the original VDO but is as close as VDO currently has.

The oem sender used by Steyr is a VDO sender. VDO does make a longer sender but the ones I found were too long for the Pinz tank. The gauge can be adjusted via a potentiometer thru a small hole on the side of the gauge body. By adjusting you basically have a choice of having the gauge read Full when full and having about 8-9 gallons in the tank when reading Empty OR reading about 3/4 when full and and having about 4-5 gallons left when reading empty. It can be a real exercise in frustration trying to get the gauge to read "properly".

Another choice is to use a digital fuel gauge from ADI. It is programmable and works with many senders including VDO. While I was able to get it to read accurately over the range of the sender, it of course shows empty when the sender reaches the bottom of its range when there is still 4-5 gallons in the tank (the "Reserve"). For my Pinz I finally settled on the newer VDO gauge adjusted to read 3/4 when Full and leaving a reserve when reading Empty.

Hope this helps.

Yeah, it did make me feel a little uneasy when I could literally watch the need drop on the way to town but if there is actually 20% more fuel not on the needle, that makes me feel better. I think I like the way VW does it on their 70's era bugs:

You have the RED reserve, but you still know how close you are to actual empty-empty.

Yeah... On the gauge, "R" looks like it's almost empty and seemingly running on fumes, but it's really running on the remaining 5 gallons!
I learned the hard way to use a large bucket to drain the "almost empty" tank.

SoCal had found some Mercedes senders that were the proper length to measure the full Pinz tank, but the round cover that bolts to the tank was different than the Pinz sender. So I modified a few for them by removing the "guts" of the Pinz senders and adapting the Mercedes guts to the Pinz cover. Unfortunately, I don't know what Mercedes sender was supplied to me so I can't do any more until it is found. I did the work for them in return for enough parts to use for myself and I do like having a full range sender!

On my other truck, I found a 24V sender and gauge set on Ebay but again, the sender can only measure abou 2/3rds of the tank depth. It is a more conventional sender with a hinged arm but I was able to mount it so that it measures the BOTTOM 2/3rds of the tank; so when I fill up I can drive 50-60 miles before the gauge gets off full, but then it measures down to the bottom.