Fuel Gauge

[Guest oshiney2]

hi guys can anyone help fitted a set of new clocks but the fuel gauge dosnt read properly reads quarter when full and full when empty i never changed the fuel sender that was sent with the new clocks just kept the old one in the tank is that my problem do i have to change it ??? can anyone help

[maccavvy]

they work on resistance and obviously new and old senders are completely different.

 

there is a device out there that changes the resistance to make it work.cant remember its name

 

but id just change the sender.

[Guest mower man]

1 wiring is reversed i.e. put the now earth to out on sender and the now power to earth that should make it read the correct way[ I think !] The gadget to correct the over reading is an adj resistor I think mark b had some dealing with one . I have just fitted a new sender to my car and have the opposite level prob to you there is around 1 gall in the tank when gauge is reading empty , i think I may leave as is . I have fitted an ISSPRO sender from Technisol it works via a vertical acting float not a swinging thing and seems to be more acurate they are ordered by length in multiples of 1 inch my tank is 8" deep so i ordered a 7" sender and the above is the result so it gives me a sort of reserve effect mower man

[Guest Tim Norman]

I saw them at Donington the looked pretty good.

[HAWKNORTH]

I had the new gauge I fitted a few years ago reading the wrong way. This was a simple matter of swapping the wires round at the sender end. hope its that simple for you.

[Guest Alan_builder]

Hi obecanobe

 

hi guys can anyone help fitted a set of new clocks but the fuel gauge dosnt read properly reads quarter when full and full when empty i never changed the fuel sender that was sent with the new clocks just kept the old one in the tank is that my problem

Yes

 

do i have to change it ???

No

 

can anyone help

Yes

 

So now I have put my foot it, so I better help

As said above the item is a variable resistor. One end goes to +12 the other end goes to 0V and the wiper is the signal to the gauge. So changing the 12V and the zero volts over will correct the full when empty.

But

On the Ford sender the 0v is manufactured to connect to the chassis.

So If you change the 12v and 0v over you will connect 12 v to ground and the fuse will not like that.

 

I cut mine up put the sensor over the other reconnected (and repositioned) to get the proper movement.

PS you may need some padding resistors as well.

 

So the easiest thing to do as you will be pulling the sensor out of the tank to modify it is to change it for the one supplied with the meter.

[Guest oshiney2]

thanks guys not that i wanted to because i was a it scared of changing the sender in the tank and it was easy as pie i just bit the bullet and changed the sender that was supplied with the new fuel gauge job done and sorted but thanks for all your help

[Guest mower man]

I saw them at Donington the looked pretty good.

Hi Tim yes they are good, not cheap £50+ but very accurate and niclely made only draw back is the mounting flange is smaller than the Ford unit I had makes for a bit of a fiddle but I have plenty of time mower man

[dandanfireman]

Aha I have the same issue with my S7 I have changed the clocks to an old set of mk2 cortina gt dials and now the fuel gauge reads arse about face as mentioned above. How would i go about fitting one of those adj. resistors? As my boot is fully boxed out and I'd rather not have to fit another sender in the tank?

 

Cheers

[Guest snowy2]

I bought kne of those universal senders with guage kits off ebay it had to be modified for a side fit but it works just fine only cost about £18 as well.

[Guest Alan_builder]

Aha I have the same issue with my S7 I have changed the clocks to an old set of mk2 cortina gt dials and now the fuel gauge reads arse about face as mentioned above. How would i go about fitting one of those adj. resistors? As my boot is fully boxed out and I'd rather not have to fit another sender in the tank?

 

Cheers

 

First I would say you can't. The emphasis is on you. I say this simply because you are asking.

Your problem is an adj. resistors thing as you say won't do what you need. You need to turn for instance 1.2 v into 10.2v and 10.2v into 1.2v and a simple adjustable resistor wont do that. You need an amplifier in fact an inverting amplifier and some offset facility and may be some non linearization. Not that complicated if you are an analogue design engineer.

 

To get the data empty your tank and fill it 1 liter at a time and note the voltage you get on the fuel sender when not connected to the fuel gauge. You will need to construct a graph. There may be a big flat section at the top or bottom of the graph, if so you need to adjust the float arm. Of course you now have to repeat the process. (At one time my float hit the tank!).

 

So now you know how many liters your tank holds so you will need to turn a dummy sender (Adjustable resistor) in that number of increments. But first you need to deduce what voltage is full scale and what voltage is empty, the voltage where the dial first get to the end not when it is banged home by 0v or 12V. You will need to use a beefy low value potentiometer say 100 ohms. With your vernier angle gauge adjust the potentiometer in 50 steps for a 50 liter tank between the 2 voltages you found above. Now you can construct another graph.

 

These 2 graphs determine the transfer function of the amplifier.

Now any one of the gents who know more about diodes than myself, as well as myself, can design you your amplifier.

[fry61]

Take the clock face off & stick on a new fuel dial --- that reads the other way -- no risk of a fuel leak then with all the faffing about at the sender end.!!!

 

OR black marker pen the "E" to an "F" & white marker the "F" to an "E". Simples --- like me.

[Jez Morton]

Has anyone looked at a "Fuel Gauge Wizard" it's a bit of electrickery that matches gauges to senders, never used one myself so can't vouch for them.

[alanrichey]

Looking to eventually replace the Escort Instrument cluster on my Superspec with stand alone gauges. On the cluster, the Tacho, Fuel and Temperature gauges each have 3 connections marked 'E', 'S' & 'B+'. The 'B+' & 'E' are common to all 3 instruments I am assuming that:

 

E = Earth

B+ = 12V

S = Sender

 

Correct ??

 

I picked up a couple of gauges at the Newark Autojumble and they have different marking. (Why am I not surprised )

The Fuel gauge has 3 connections marked 'Earth', 'B' & 'T'.

The Temperature gauge has only 2 connections marked 'B' (or '8') and 'I' (or '1' or 'T'), although I assume the case will act as Earth ?

Is 'B' the same as 'B+' ?, i.e. Power. And are 'S' & 'T' the same ?

And like many of us my present gauge displays backwards. Don't really care if the new one works correctly or backwards, but is there any danger (fuse overload) in just substituting the new one for the present one. ?

 

Al

[Guest mower man]

B = bat or battery ,T = tank athe other is obvious as to o/load I would not think so mower man