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S3 Fuel Level Sender

PostPosted: Fri Jan 08, 2016 5:53 pm
by fattogatto
I've done a search and can not determine if anyone has found a replacement fuel level sender. I've heard the Jeep sender will fit and also Holden vintage Senders has a fit. But the ohn rating is way off. Nisonger says I need 1-3 ohms empty and 80 ohms full. I've read some say 0 - 90 (Nisonger says this will be inacurrate) or 30 - 230 (which is totally inadequate for my needs.)

Has anyone come up with a suitable fix. My unit is not repairable. Of course, the 6 bolt pattern on the tank adds another issue.

An option is to find someone with a repairable unit.

Re: S3 Fuel Level Sender

PostPosted: Fri Jan 08, 2016 7:18 pm
by mbell
fattogatto wrote: I've heard the Jeep sender will fit ....


I think that might be in reference to a comment from me. Note I only know the plastic float from the Jeep fits the standard sender arrangement (on +2) not that the Jeep sender is usable, I doubt that it is.

Re: S3 Fuel Level Sender

PostPosted: Sun Jan 10, 2016 12:10 am
by Mike Ostrov
I just measured the resistance with both analog and digital meters. Average is: 235 to 40. This sender is from my S4 1969 in excellent condition #TB 1114/023. Hope this data is helpful. Still have many S2 and S4 suspension and engine parts for sale and a S2 toneau LHD cover. Cheers. Mike in Richmond, CA near SF (510) 232-7764

Re: S3 Fuel Level Sender

PostPosted: Mon Jan 11, 2016 10:14 am
by Keith Scarfe
Coincidence!!! I have just taken mine out to investigate why it is not working and have it sitting here in front of me. Mine has broken windings and I think (hope!!) it can be repaired. Speedy cables does this I think. I will be contacting them soon so can report back.
The reason for this post is to say that the S3 one (and earlier I think) as far as I know is different to the S4 one. It is the ohm range from empty to full but it does obviously depend on which gauge you have. The gauge must match the sender. My one, the S3 one, goes (or rather did when it was OK as I measured it a while ago) from 0 at empty to about 230-250 at full but I don't think the full value is too important because you can tune the gauge using the little sliding screws on the back to match the sender. Mine has the part number TB 1114/020 i.e. the difference between mine and the one mentioned for the S4 is the 020 - 023 at the end.
I am pretty sure no one (Miller, Mattey etc) will have these any more but I will make a couple of calls.
Regards.
Keith.
p.s. mine has been broken for a couple of years now and I have learnt to use the mile trip in the speedo combined with a long dip stick as my fuel gauge so I am not too bothered if it cant be fixed. Ill just plug the big hole in the tank and carry on driving.

Re: S3 Fuel Level Sender

PostPosted: Mon Jan 11, 2016 12:03 pm
by ericbushby
Kieth,
If you are sure that the sender you need is the 250 ohm version then I found an easy and cheap fix.
I bought a new sender for a Minivan locally from J and K supplies. They are on ebay at ?18.00 plus.
They do not specify the resistance, so I called in and measured one.
The six holes need to be redrilled to put the sender upright and the float arm needs to be extended 2" to give the required 9" total swing for our tanks.
I am content with the result.
Thanks are due to Ron on here for the suggestion.
Hope this helps
Eric in Burnley
1967 S3SE DHC

Re: S3 Fuel Level Sender

PostPosted: Mon Jan 11, 2016 12:21 pm
by RogerFrench
I think there are 2 kinds of fuel gauge. One is moving coil, and is the kind that responds quickly. It was fitted to earlier cars.
The other is the bi-metallic strip kind, which responds much more slowly, and was fitted to later cars. My S3 has this kind, though I strongly suspect a PO retrofit.
The two kinds require different senders. The bi-metallic strip kind also uses a10v voltage stabiliser. With this kind a high resistance, somewhere just over 200 ohm, indicates empty, low resistance, about 20 ohm, is full.
The early type has low resistance, 0 ohm or so, when empty, about 80 or so when full.

The above is from memory, my numbers might be off a bit but the principles are right. Don't mix the senders.

Andy Wiltshire, Axminster panels, supplied a sender with correct arm length and hole orientation.

Re: S3 Fuel Level Sender

PostPosted: Mon Jan 11, 2016 2:23 pm
by fattogatto
Info is great. Unfortunately Axminster Panels only has the S4 sending units and the 1 - 80 ohm units appear to be unobtanium. Might be able to make an inductive type replacement. The 6 bolt flange is also an anomaly apparently.

For the electrical engineers - any way of changing the resistance in a 40 - 230 ohm unit to mimic the 1 - 80 ohm unit?

Re: S3 Fuel Level Sender

PostPosted: Mon Jan 11, 2016 2:51 pm
by Keith Scarfe
Wow. By typing in the part number (not Lotus or elan) into a search, I found one for sale the same one as I have.
Here:
http://www.ebay.co.uk/itm/141822692719?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

A triumph one - seems plausible.
I didn't expect that, I thought all this stuff was NLA. anyway, now my memory starts whirling...... I think I might have a non standard one in mine. When I first got my elan back in the 1980's, I remember the tank was just a pile of rust so had to replace it and the sender. I would have brought the sender from one of the main suppliers like Mattey and I now recall having to buy a gauge and sender together as the sender was even then NLA. Looking at the picture in the above link, the arm is not the correct shape for the elan tank and I do remember having to bend out that right angle, cut it to length and reform the semi circle for the float to locate in. So my plight may be answered, sorry not to help yours but you may like to search this seller for a similar part. I have ordered one any way since it is only ?25 and will see if it works.
Cheers.
Keith.

Re: S3 Fuel Level Sender

PostPosted: Mon Jan 11, 2016 3:04 pm
by fattogatto
I think the ohm range on that unit is 10 - 180.

Re: S3 Fuel Level Sender

PostPosted: Mon Jan 11, 2016 3:33 pm
by Keith Scarfe
Oh OK, well I have ordered one anyway. Should be here by the weekend. I just went by the part number and that it looked the same in the photo. Ill try it and let you know.
When I measured mine a few years ago it defo went from 0 (empty) to 210 (full tank less about 10 miles). I have my notes from then. But like I say I may have a different gauge to yours. Anyway Ill report back next week.

Re: S3 Fuel Level Sender

PostPosted: Thu Jan 14, 2016 9:51 am
by Keith Scarfe
Just to follow up if you are interested. The sender arrived yesterday (good ebay seller) and I tried it last night. It does seem to go from 30 ohms at empty to 260 at full. My original one defo hit zero ohms (short) at empty and when I connected it to my cars wiring it does indeed indicate about 1/4 on the gauge at the empty position. Full is fine. As I said earlier I am 99% sure I will be able to set the sliders on the back of the gauge to tune it exactly to the sender as I did this before on the old one to get it to read exact.
Now just got to bend the arm to shape (I can see on my old one exactly where I did this, so they were the same) and refit it.
Cheers.
Keith.

Re: S3 Fuel Level Sender

PostPosted: Thu Jan 14, 2016 2:06 pm
by ericbushby
Hello Keith,
It sounds like that sender should be OK.
My bimetal guage has no adjusters and I get a good swing from marginally over zero to full.
But with mine a lower resistance allows more current to flow and gives a higher reading. It is a simple thing.
Therefore:- 250 ohms gives empty and low reading shows full.
If the fixing holes are in the right position and the arm is the correct length, then at ?25.00, your solution is better than mine.
Cheers
Eric in Burnley
1967 S3SE DHC