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fuel gauge

PostPosted: Fri Oct 14, 2005 1:03 pm
by thor
Had some erratic running of the car today going to work, and my petrol warning light has been on since the last drive. I now wonder whether the car might actually have been running out of petrol. But the gauge is not on the E field yet, about 3mm from it, so am I just cutting it too thin, how far to the left does the fuel gauge go before empty?


Re: fuel gauge

PostPosted: Fri Oct 14, 2005 3:05 pm
by john.p.clegg
The only way you're going to calibrate that is to drive around with a spare can of fuel,when it stops-it's empty

Re: fuel gauge

PostPosted: Fri Oct 14, 2005 4:16 pm
by Hamish Coutts
After working on my tank (which meant I had to empty it) I put in 1 gallon of petrol. When I turned the ignition on, the red low fuel warning light was still on. It took about another ? gal to make the red light go out. So I recon for me, I have around 50 miles range when the light comes on.
I don't think the guages are particularly accurate anyway. Does it really matter if the needle doesn't drop right down?

Have you checked wrere the needle sits when you turn off the ignition? Does it drop down further or stay where it is? Could be the transmitter is either faulty or sticking somehow. Take it out and have a look to see if the mechanism moves freely.


Re: fuel gauge

PostPosted: Fri Oct 14, 2005 5:32 pm
by tonycharente
On my Baby Elan when the fuel gauge read 1/8 the car ran out of fuel, and when the tank was totally full the gauge read off-the-gauge-full. It turned out that for reasons unknown the P.O. had taken the voltage stabilizer out of the circuit, so the gauge was getting a variable +- 14 volts instead of the steady 10 volts it needs. (Actually it's not at all a steady 10 volts - the voltage stabilizer cuts in and out all the time so as to give an average of 10 volts). Wiring the gauge via the voltage stabilizer cured the fuel gauge problem.

How do your other gauges (oil and temperature) seem to read? The reason I ask is that on the +2 the oil and temperature are, I believe, also electric, so if your voltage regulator is either not working or disconnected, then I would expect these also to be over-reading (that would be good news on the temperature front, not so good on the oil pressure front though.....). If these other two gauges are reading accurately, then it could still be that the fuel gauge has been wired up direct (like mine was).

Worth a look? The voltage stabilizer is a little metal box, normally screwed onto the back of either the speedo or the tach. And oh yes, there is also a way up to its mounting (has to be mounted with the bracket coming down vertically, or it won't work properly).

No idea if this has any relevance to the fuel low warning light I'm afraid. Hope this helps,

Re: fuel gauge

PostPosted: Fri Oct 14, 2005 6:14 pm
by elans4dhc
When I had my fuel gauge restored professionally - can't remember who at the moment - I was asked to also send the sender unit so that one could be calibrated with the other. Gauge reads perfectly now.


Re: fuel gauge

PostPosted: Mon Oct 17, 2005 8:17 am
by fasterbyelan
Two issues regarding this thread which may be of interest to both Elan and +2 owners.

1 If running the fuel tank low/empty to check gauge position, ensure that the fuel tank is clean. Sucking up crude will give you a few hours work! It is such a easy job on the Elan (not sure about +2) to remove the tank that a yearly clean/flush is practical.

2.The fuel gauge on my Elan has only ever read between 1/2 and full. This is due to the incorrect fuel gauge sender unit being fitted by the PO (S1 & 2 type fitted to a S4 car).

Hope this is of help.


1970 S4 FHC SE

Re: fuel gauge

PostPosted: Mon Oct 17, 2005 10:32 am
by thor
"Sucking up crude (crud?) will give you a few hours work...."

Are you by this saying that this will take time when you're in the process of cleaning the tank, or, as I am fearing, this will cause the fuel system and engine, MINE NOW to get gunked up and thereby wanting a few hours work....?

I've had problems with stalling this weekend, after running low on petrol, this is why I'm asking....and it's continued now after filling up.

Re: fuel gauge

PostPosted: Mon Oct 17, 2005 2:22 pm
by fasterbyelan
Sound suspicious !

I ran out of fuel as I arrived at a petrol station and, after filling up, the car would not start and had to be recovered home via the RAC. Apart from all but blowing the baffles out of the exhaust trying to start it, I had to clean the whole fuel system out - fuel filter/gauze in pump, carbs, fuel pipe and tank (I susequently replaced the tank as it was paper thin at the bottom).

Thankfully once complete the engine started straight away and a lesson was learnt. I had only been running the Elan a few days since I bought it at the time so there was a lot to discover.

Hope this helps.


1970 S4 FHC SE

Re: fuel gauge

PostPosted: Mon Oct 17, 2005 2:44 pm
by wildoliver
Well i recently had the opposite problem on my baby elan, after my bump the tank developed a leak caused by the mount ripping out of the bottom, from the inside the tank looks like new!!! and top and sides are like new, but the bottom was nigh on non existant!!!!!

Anyway have welded a new bottom in now!

Good as new!!!

Re: fuel gauge

PostPosted: Mon Oct 17, 2005 2:59 pm
by thor
So what's a good temporary procedure for this then, as I'm about to put mine away for the winter, and have very limited time to do this now!, but leaving it over the winter with a gunked up fuel system does not sound good!

- Carbs: This is my first car with webers, what's an easy good way of cleaning them, and are the spray-on carb cleaners any good?

- fuel pipes: How on earth can I clean them?

- will check the fuel pump gauze and petrol filter.


The car seemed to improve after a good thrashing on the motorway on saturday going back home from work, after wanting to stall but picking up again three times going there..

Re: fuel gauge

PostPosted: Mon Oct 17, 2005 3:17 pm
by fasterbyelan
Regarding cleaning the fuel system, remove the tank and drain out the contents via the neck after swilling it around a bit. If you have rust inside the tank you will soon know. I would not use the drain hole as the rate of flow is too low and you will need to repeat the operation a couple of times.

After disconnecting the fuel pipe at the pump I probably fitted a length of neoprene pipe to the fuel pipe, tank end, and blew it out. I do not have a separate fuel filter so that is not an issue for me.

I cannot comment on Weber carbs as my Elan has Strombergs, which are relatively easy to clean out.