VDO fuel gauge sender replacement. Where would I find one of these?

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cygnusv

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This is from a late 70's Fairline 36 Sedan. I've been struggling to find a straight match and wonder if anyone on here has any ideas. I've measured the max resistance on this unit and its showing about 300 ohms. I'd like to find a match if possible to avoid having to replace the gauge too, it being one of a pair. Any input much appreciated.
 

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cygnusv said:
This is from a late 70's Fairline 36 Sedan. I've been struggling to find a straight match and wonder if anyone on here has any ideas. I've measured the max resistance on this unit and its showing about 300 ohms. I'd like to find a match if possible to avoid having to replace the gauge too, it being one of a pair. Any input much appreciated.
Click to expand...

Is that at the empty end of the float's movement? European gauges tend to work on around 10ohms empty, rising to 180ohms when full. US gauges work the other way round, with around 240ohms empty and 30 ohms full. I'd expect it to be a European sender.
 
pvb said:
Is that at the empty end of the float's movement? European gauges tend to work on around 10ohms empty, rising to 180ohms when full. US gauges work the other way round, with around 240ohms empty and 30 ohms full. I'd expect it to be a European sender.
Click to expand...

I was going to mention the usual EU spec of 0 - 190 ohms ... but he mentioned 300 ...

Have a feeling his 300 may be because of the condition of the unit ?
 
pvb said:
Is that at the empty end of the float's movement? European gauges tend to work on around 10ohms empty, rising to 180ohms when full. US gauges work the other way round, with around 240ohms empty and 30 ohms full. I'd expect it to be a European sender.
Click to expand...
The gauge's on both tanks are banging across straight to full. I've tried new temporary wires but that didn't work. The common ones I've seen do go up to 180ohms. If I can't find an identical sender I intend to use the 180ohms one with matching gauge
 
Judging by the pics it looks like a VDO swinging arm type.

You may want to check the catalogue on the following site:

www.furneauxriddall.com

Personally, I replaced my swinging arm type with a "tube" type which is easier to calibrate (just buy the correct length for your fuel tank);they have the same profile of fixing flange as the lever arm type; the same electrical connection (two wire) and resistance. So, a very easy "plug and play" replacement. The cost of the lever arm type and the tube type are very similar.

[Up until a few months ago they were selling both types but now seem to have dropped the lever arm type!!]


Alan.
 
pvb said:
That would suggest an open circuit. If you short out the 2 wires at the senders, do the gauges show empty?
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Interesting. I haven't shorted them together but will tomorrow. Where would that suggest the open circuit is? In the sender itself? As I mentioned earlier, I completely by- passed the existing wiring in case there was a problem in the wiring, but to no avail.
Also, have VDO always used the 180 ohms figure for a full tank? If so it would suggest that my reading is faulty due to age of unit.
Many thanks
 
cygnusv said:
Interesting. I haven't shorted them together but will tomorrow. Where would that suggest the open circuit is? In the sender itself? As I mentioned earlier, I completely by- passed the existing wiring in case there was a problem in the wiring, but to no avail.
Also, have VDO always used the 180 ohms figure for a full tank? If so it would suggest that my reading is faulty due to age of unit.
Many thanks
Click to expand...

Open circuit could be in wiring, or in sender.

Check what happens on the gauge when you short the wires.

No idea whether VDO have always used 180 ohms, but I suspect so, on the basis of "if it ain't broke...".

The sender units do fail; the potentiometer track degrades, or the contacts, or the internal wiring.
 
cygnusv said:
This is from a late 70's Fairline 36 Sedan. I've been struggling to find a straight match and wonder if anyone on here has any ideas. I've measured the max resistance on this unit and its showing about 300 ohms. I'd like to find a match if possible to avoid having to replace the gauge too, it being one of a pair. Any input much appreciated.
Click to expand...
Friend of mine had the same problem and asked if I would check it for him. The sender was the same type as shown in your photo. Due to the moisture in the diesel the sliding contacts "inside the plastic assembly" that connect to the two spade terminals were in fact making a bad connection.
The unit has the sliding contacts to allow you to make fine adjustment to the position of the swinging arm - top and bottom level.
If you very carefully dissasemble the sliders, make note of the position, and clean the brass with say a bit of Scotch Brite or very fine emery paper, reassemble and re connect you will find your fuel level meter will work.
 
Big John said:
Friend of mine had the same problem and asked if I would check it for him. The sender was the same type as shown in your photo. Due to the moisture in the diesel the sliding contacts "inside the plastic assembly" that connect to the two spade terminals were in fact making a bad connection.
The unit has the sliding contacts to allow you to make fine adjustment to the position of the swinging arm - top and bottom level.
If you very carefully dissasemble the sliders, make note of the position, and clean the brass with say a bit of Scotch Brite or very fine emery paper, reassemble and re connect you will find your fuel level meter will work.
Click to expand...
Excellent. Thank you for that I'll give it a go. ?
 
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