Faulty fuel gauge or sender

[leifanten]

Hi I have a fuel gauge / sender that results in the following:

the warning light comes on and goes off as it shall, but the needle does not move at all. I ohmed the sender, and when full it reads open circuit. I would say that this points to a busted sender (at least in the full position) If I get a reading as the fuel level drops that would conclude the matter.

Sounds like I have solved my problem before posting it unless there is something here that I am missing?

Leif Andre
Houston, TX

[1964 S1]

Greetings,
I'd say you probably nailed it... the archive here has oodles of info on this...
I believe the only thing you're missing is you don't need one, unless your car is a daily driver down there in hot Texas.
My +2's light works, and flicks on and off with sloshing, that's all I go by, the gauge is erratic.
My S1 gauge? ha! I use a wooden dip stick with two depth markings on it to see how much fuel is on board.
I haven't run out of gas, yet.
Do you have a 45 or a 50?


Eric

[leifanten]

mine is 50/1136 it is wedgewood blue (I love the color more every time I see it) with black interior.

As long as you dont go down the route of a customer that came to a friend of mine at the local ford dealer and asked if he could buy a longer dip stick for his engine, since the one he had did not reach the oil anymore...

[69S4]

Hi Leif

You should be able to check the gauge by just pulling the wires off the sender and connecting them together. Assuming the wiring is ok (never a good thing to assume with a Lotus ) the needle should head towards the full mark.

If, as sounds likely, it's the sender you can open it up and check the state of the wiring inside by bending the little tags. When I was doing mine back in the summer everything looked fine but it just didn't work. I eventually found a non conductive soldered joint - not broken, just non conductive. After bridging it the gauge has worked for the first time in 10 yrs.


Stuart

[blackandgold]

In my car the sender had frozen solid after a long storage period
so the float would not lift when fuel is in tank

It is still this way as car has not been used

I guess it would free up after if it was removered and sprayed with CRC

[69S4]

In my car the sender had frozen solid after a long storage period
so the float would not lift when fuel is in tank

Yes, I had that problem with my sender as well Took it out of the tank and found the float arm was stuck. Took it to bits and found the
bearing area where the arm goes into the body of the sender was full of a chalky type of fuel deposit. Freed it up and put it back in the tank -
still didn't work (till I fixed the wiring fault).

Stuart

[leifanten]

Thanks for good advice! I will need to drive the tank to a level where it is safe to remove the sender, and I will give it a go.

I loved the comment about "unless you use your Lotus as a daily driver..." Even when they were new they were hardly even daily starters...

Leif Andr?

[stugilmour]

Leif:

Welcome aboard as well.

Agree it sounds like the sender has given up. If it turns out the sender is completely gone, I thought this one might just fill the bill. Ends in about four days, and might have to check first if he will post to the States. Anyway, just took another look and edited this post; eBay pic is rather small, but looks like a two terminal sender, and you need the one with three terminals

http://cgi.ebay.co.uk/Lotus-elan-2-petr ... 286.c0.m14

Was thinking about the post above mentioning jamming of the float. If the float is in fact jammed at the very bottom (i.e. empty tank), the sender will read open circuit. However, if I am reading your original post correctly, the low fuel warning light works correctly? This would be indicative of float & ground working correctly over at least lower 1/4 of travel as the warning lamp uses the same float, just different switch within the unit.

As with everything Lotus, check the grounds carefully on anything electrical before assuming the component is faulty. If the low fuel lamp is working correctly though, I expect the ground on the sender unit is OK. Both gauge & low fuel lamp use gorund @ the sender.

Here is a recent thread on the issue. Mine is completely out of the car, so was able to manipulate it, etc. The sender should have some resistance at full reading, but open at empty.


elan-plus-f13/how-much-fuel-can-your-tank-take-t18610.html

[yandy]

I will need to drive the tank to a level where it is safe to remove the sender

What? No useful hills for tank-work in Houston?

[RotoFlexible]

Hello Leif,

Nisonger can rebuild senders as well as instruments. (They rebuilt mine.) I have an Elan S2, two-terminal sender, no warning light - so take the following for what it's worth. When I was bench-checking the fuel gauge and sender after receiving them back from Nisonger, I couldn't get them to work. I called Nisonger; they reminded me that the fuel gauge case needs to be grounded to make up the circuit. I have no idea if that applies to your situation, but something to keep in mind.

[leifanten]

I have checked that it is grounded, and since the light works, I assume that a) the grounding is sufficient and b) the float moves.

I am going to short out the sender to check the instrument before I start disassembly.

The only hill steep enough to do tank work in Houston would be the shoulder of one of the major highway flyovers, and I am not sure that is a safe place to be doing anything

cheers
Leif