MkIV fuel gauge problems

[AC Ace Bristol]

quote:Originally posted by MkIV Lux
   

quote:Originally posted by AKL 1333
   
Hallo Constant,
   kannst du nicht einfach die Platte mit dem Sensor rausschrauben und  die Kontakte anfrischen und etwas auflöten?
   Liebe Grüße
   Jürgen
   

   
   Hello Jürgen,
   
   Yes I could take the plate and sensor out and repair it. But before doing so I rather have an alternative ready to close the whole, in case repair is tricky. Can't leave the petrol tank open and when it is open, after having drained all fuel it would be wise to have the remaining petrol fumes be neutralized by inert gas. So it's not that easy. Better have this done by a specialist shop, I guess.
   

   
   Constant
   
   When we had to weld damaged fuel tanks during Stage / Forest Rallies during the 1960s / 1970s.  we used to fit a tube over the exhaust and discharge into the fuel tank.  Carbonmomoxide Nuetratised the fuel vapour?   We never had a major problem,  Or were we just bloody lucky ??
   
   Might be worth getting a distant friend ( or enemy) to check out first.
   
   Keith

[MkIV Lux]

quote:....
   
   
   When we had to weld damaged fuel tanks during Stage / Forest Rallies during the 1960s / 1970s.  we used to fit a tube over the exhaust and discharge into the fuel tank.  Carbonmomoxide Nuetratised the fuel vapour?   We never had a major problem,  Or were we just bloody lucky ??
   
   Might be worth getting a distant friend ( or enemy) to check out first.
   
   Keith
   
   
   

   
   Hi Keith, good to read you ... []
   
   Guess you had a good portion of luck in your baggage[8D]in the old days.
   But you are right. Carbonmonoxide absorbs the oxigene (as I remember from the chemistry course some tens of years back) => so no oxigene left => no fire / no explosion, since oxigene and fuel vapour are required. All makes sense [^]

[AC Ace Bristol]

Constant
   
   Well, we didnt see or hear any major exlposion over Luxembourg, So I must ask,  Is the MK1V  up and running or still hibernating in the garage ?
   What course of ACtion did you take ?
   
   
   Keith

[1984MkIV]

Another question concering fuel gages: I changed the fuel gage, bu could change the sensor. The sensor of the new gage doesn´t fit to the safety fuel tank (it works like the valve in the water toilet and needs space to swim!).
   If fuel is low, the gage shows a little bit less than 3/4. If it is empty, it shows "full" (maybe I have to reverse the fuel pump []!).
   I remember vaguely that there was something like I = U / R. That´s why I think I have to measure the resistance of the sensor with full and emty tank. Then I have to try out, what the gage shows depending on the Input. That´s where my knowledge of electrics ends (I know there is + and - and you need both connected to get some reaction - that´s it).
   
   Question #1: How can I measure the Input the gage needs to show "empty" and full (I guess it works proportional)! Further on I guess, I have to put some resistors into the circuit. Question #2: Where? And I guess I have to calculate, which resitors I need to get the fuel level aligned with the indication of the gage? Question #3: How can I calculate the resistances of these resistors?
   

[MkIV Lux]

quote:Originally posted by AC Ace Bristol
   

   Constant
   
   Well, we didnt see or hear any major exlposion over Luxembourg, So I must ask,  Is the MK1V  up and running or still hibernating in the garage ?
   What course of ACtion did you take ?
   
   Keith

   
    Cleaning and modifying the broken contact by fixing the incoming grounding wire to one of the screws did the job finally.
   As you know, this allowed me to go to Castle Combe without having to stick my finger into the tank, and this past w/e I had made a trip to Monza for a day on the F1 track. My route via 3 Swiss mountain passes did not affect the correct functioning of the gauge [][].
   Now I'm a happy man again []
   
   
   

[REV]

Just wondering if anyone actually knows how to alter the sensor so it reads correctly? Mine stays full for ages (relatively ) and then plummets. The gauge reading when the tank is empty shows 1/4 full. This isn't so bad now I know, but a little embarrasing when I first found out!
   
   Just thought if anyone had a simple fix I'd remedy the problem.

[marklotus]

Does anyone know what the gasket is for the fuel sender.  Mine is leaking.  I would rather put on a ready made one than make my own.
   Thank you,
   Mark

[MkIV Lux]

the story goes on ....
   In the course of 2011... the fuel gauge sender unit made further trouble, such that I decided to take it out, and replace it by an aluminium plate to ceil off the whole.
   
   And had to fill the tank and keep a serious eye on the mileage indicator to make sure I did not run out of petrol! Unsatisfactory solution.
   
   Doing a lot of research on the internet and contacting a few (not all) of the Cobra specialists, to find a one to one replacement fuel sender unit (see pictures):  I have not been successful though!
   
   Maybe someone here has already gone through a similar exercise for the same equipement.
   
   Stewart Warner fuel gauge on the dashbord (should be kept in place; I don't want to switch to a Smith gauge).
   Resistance of the sender is 250 Ohms. Tank is flat under boot type. Sensor feeds are for reserve indicator and for level indicator.