Litrometric failure, fix needed!!! - Page 2

T-Cut · 14th March 2012, 22:47

Quote:

Originally Posted by phunk3r

Dear T-CUT, can i measure those pins and see if the sensor is working fine?

Whatever quantity of fuel is in the tank, the two resistances should be within the range noted on the image. It won't tell you if the floats are working properly. To do that, you would have to remove each one and check the resistance when you move the float up and down.

Quote:

Do you know which value means empty and which full?

No, sorry I can't remember. The above test will show it.
If you remove a float unit, it can be difficult to refit so it is free to move fully in its range. There is very little room to maneuver so it must be positioned correctly.

TC

]

phunk3r · 18th March 2012, 10:32

Quote:

Originally Posted by T-Cut

Whatever quantity of fuel is in the tank, the two resistances should be within the range noted on the image. It won't tell you if the floats are working properly. To do that, you would have to remove each one and check the resistance when you move the float up and down.

No, sorry I can't remember. The above test will show it.
If you remove a float unit, it can be difficult to refit so it is free to move fully in its range. There is very little room to maneuver so it must be positioned correctly.

TC

]

i have changed both of the litrometrics, but as i have noticed, the one that i replaced had 4 contacts besides the many dials and the new one, just 3 contacts... do you know anything about this?

and another question... there are 2 sides of the fuel tank... the one just with litrometric and the other one with the actual pump... can anybody explain how they work? because as i noticed that the fuel is sucked by the one with just the litrometric....

THANK YOU ALL!!!

T-Cut · 18th March 2012, 12:25

Quote:

Originally Posted by phunk3r

another question... there are 2 sides of the fuel tank... the one just with litrometric and the other one with the actual pump...

As noted earlier, there is a fuel level sender/float in each side of the tank. The pump module should have one as well.

Quote:

can anybody explain how they work? because as i noticed that the fuel is sucked by the one with just the litrometric....

Here's a simplified diagram of the tank and the main components.

The primary electric pump, whether diesel or petrol, is a centrifugal type generating 50-60psi in the outlet line. This means it can run against a closed outlet while maintaining delivery pressure. It must also be adequately primed and to ensure this, the fuel pump is fed from a permanently flooded pickup or swirl cup. It’s the job of those other two pumps to keep the swirl cup full. In the average situation, the electric pump and its swirl cup are completely submerged, so while there are transfers happening within the tank, they only become needed when the inventory drops.
The two secondary in-tank pumps are static inductors based on the Venturi principle. These get their motive power from pressurised fuel generated by the electric pump (petrol) or the diesel’s HP injector pump back-flow from the engine. Their sole purpose is to ensure the swirl cup remains full under all conditions. Since they will only work when pressurised fuel is fed into them, any circumstance which reduces this pressure will cause a tank malfunction. For example, the diesel HP backflow passes through the cooler mounted externally near the tank. A fuel leak from the cooler may inhibit delivery from the inductors. Similarly, FFS in the petrol tank may inhibit feed to the inductors. This will also cause tank malfunction and explains why FFS is sometimes accompanied by an absence of fuel in the RHS.

FrenchMike · 18th March 2012, 15:56

Quote:

Originally Posted by phunk3r

Dear T-CUT, can i measure those pins and see if the sensor is working fine? and do you know witch value means empty and witch full?

Thank you for all this tremendous information! i will go to my mechanic and check this out!

Hi,

Here it is:

Connect.jpg

Mike

phunk3r · 19th March 2012, 08:42

Quote:

Originally Posted by FrenchMike

Hi,

Here it is:

Attachment 12784

Mike

Dear all,

first of all I would like to thank everybody for their support...

second, i would like to ask if i can test somehow the fuel pump... in order to see if it functions correctly... because i think that it is lazy and when the tank is low on fuel it simply cannot suck it all out...

again many thanks!!!