Fuel Tank

[PhilDKE776K]

I am a new E Type Series 3 owner and I am confused by the fuel tank capacity. According to my original handbook the petrol tank holds 18 Imp. Gals, but even when I run the car to very low, I can only fill up with max 13 gallons. Looking at the tank and the workshop manual ,they look the same.
I am loathed to run it till empty, as there could be all sorts of cr*p at the bottom of the tank!
Any help would be most welcome on these thoughts;

1. Did E Types ever have reserve tanks fitted, as some Jags. did?
2. Where smaller tanks available and maybe fitted during a past refurb?
3. Would fuel gauge be faulty?
4.Is there a sensor in the tank which could also not be operating properly.

Any help will be much appreciated!

Phil

[MarekH]

1/ No
2/ No
3/&4/ These two are linked, literally. The fuel sender has two parts. One is for the fuel gauge, but there is a second element inside which feeds the "fuel low" light. This will typically come on at about just over one left in the tank. If the fuel gauge appears to run from full to empty, then it is probably working right.

Worrying about debris n the tank doesn't help, since the pickup is at the lowest point inside the sump.

If you have an averagely bad US import with a 3.56 differential and an autobox, expect 11mpg. If you have a UK spec car with well maintained carburettors, then 17mpg is achievable. Expect to be somewhere in between. If you fill up 16 imperial gallons, budget accordingly when resetting the trip meter.

There's a reason why I fitted fuel Injection and LPG to y car. On a long run, it returns the cash equivalent of 40mpg and higher figures are achievable.

If you think it reads "high" and the temperature also appears "high", check the green/black that the green/black wire reads 10v and not higher.

kind regards
Marek

[PhilDKE776K]

Thank you Marek most helpful. I seems from what you say that I have not got a smaller tank, just a misreading fuel gauge!
The most I have been able to put in the tank is about 55L or 12 gallons when the gauge is reading almost empty - I have never had a low fuel light come on.
Perhaps, as you say as the pipe feeds from the bottom, I should keep driving, safely, till I run dry. Of course, having spare fuel on board!
Phil

[MarekH]

To check whether the fuel light is functioning properly, swap the bulbs over between the holders feeding the orange fuel light and the working red ignition light. If the ignition light no longer lights then swap the bulbs back and fit a new bulb into the fuel low position. If the ignition bulb lights but the fuel low bulb doesn't, go to the boot and earth the white/green wire. If the bulb lights now, you either have a faulty sender or have never emptied the tank. If it doesn't light, you have a wiring problem. It's relatively easy to pull the three wires from the fuel sender and remove the sender for testing. You can also peer in and see the fuel level. Since you only ever put 13 gallons in, it is quite possible everything works and you have never run the level down enough to trigger the orange light.

kind regards
Marek

[Colin]

Hi Phil
Picking up on what Marek said it sounds like your fuel gauge is under reading the amount of fuel in the tank. You could try checking the earth on the voltage regulator which sits behind the drop down instrument panel LHS especially if your water temperature gauge is over/under reading then try cleaning the thread that holds the regulator or add an additional earth if necessary- that’s a possible no cost solution. The voltage regulator reduces 12v to 10v as Marek indicated which serves the fuel gauge and the water temperature gauge. Of course it could be the voltage regulator itself which is faulty but is not over expensive to replace. Also could be the fuel sender in the tank but that sounds like it’s working. Your not getting the low fuel light up on your dash as it sounds like you still have a few gallons left in the tank
Good Luck
Colin W
S3 V12 2+2 1973

[MarekH]

Just to be clear, the fuel sender in the tank has two totally separate circuits:- one for fuel light and one for the gauge. Their only thing in common is that they share an earth wire. It's quite possible for one to be working and the other not.

kind regards
Marek