How To - Understand Fuel Tanks

[FrenchMike]

About the ITP's ,in the 2006 /2007 ,when the first failures appeared ,
Members were advised to replace them by the Peugeot 407 insert.(petrol)

That is what i did and is still working strong


Mike

[T-Cut]

Originally Posted by 2.2-600-vtec

Does anyone know if the intank venturi pumps are the same be it petrol or diesel? as in as our cars get rarer and older can fuel parts be interchanged between the what appears more common diesel to the petrols?

It's highly unlikely that the venturis will ever need replacing. They're a simple static device with no moving parts. They're powered by the electric ITP and in the diesel by high pressure return from the injectors. They're also integrated with the tank modules so aren't really accessible. The main issue long term is the electric pumps as Mike has mentioned.

TC

[COLVERT]

Just seeking a bit of info. ( Needed cos I'm old. Lol.)


In TC's diesel tank diagram the Venturi pumps seem to be operated by the return flow from the HP pump on the engine.

If the in-tank pump has failed but the engine is still running using the under-bonnet pump won't there still be surplus fuel being returned to the tank. ( As above post, by high pressure return from the injectors. )

Why won't this fuel still operate the venturi action to level the both halves of the tank ??--


Could be not enough returning I suppose.---

[HarryM1BYT]

I don't think it will be high pressure, just a few bar at most, it is only the leak off/ the surplus fuel, which runs through a much larger pipe. Larger pipe, lower pressure.

If due to ITP failure, then there might be enough fuel pumped by the UBP to run the engine, but not a lot of surplus to the engines needs, to produce the level of vortex needed to transfer the fuel across.

[2.2-600-vtec]

Reading the whole thing it looks like there would be enough fuel to allow the venturi pumps to work, i dont think thats the issue, the problem is that, at 1/4 level the in tank pump top is no longer submerged, this is the part that the self bleed valve vents off when the pump has air in,once the in tank pump bleeds the air out the valve is shut off by the diesel pressure produced by the pump,
When the intank pump fails and the car runs on the UBP, there is no pressure to close the valve off, so the UBP that has to draw fuel through the in tank pump, so in respect there is a negative pressure acting on the bleed valve holding it open,
at a guess the UBP takes all its fuel through the bleed valve instead of through the intank pump as this would be a major restriction, anyway due to this as soon as the fuel level drops uncovering this valve the UBP can only draw air as thats all thats there. hence the 1/4 full running issues.

To my original question in a round about way although the venturi pumps are sealed inside are they made of the same materials?
due to a technical reason i want to use a diesel fuel tank on a petrol.

Thanks
Nathan

[T-Cut]

Originally Posted by 2.2-600-vtec

the problem is that, at 1/4 level the in tank pump top is no longer submerged, this is the part that the self bleed valve vents off when the pump has air in

Yes the HowTo goes into that. What then happens is the UBP will receive aerated fuel. This causes it to become noisier as gas bubbles enter the pumping chamber. Though many UBPs survive a long time after the ITP fails, some die shortly after.

TC

[Shuriken_57]

Hello guys, are the diesel tank and petrol tank the same?
( Only the structure not the pump and wires)
Thanks you.

[T-Cut]

Originally Posted by Shuriken_57

Hello guys, are the diesel tank and petrol tank the same?
( Only the structure not the pump and wires)
Thanks you.

Hello again Brahim, the outer plastic tank is basically the same for petrol and diesel systems, though there may be access points in one, diesel for example, that aren't used/blanked off for petrol models. I'm guessing I'm afraid. It's not a question that often comes up. You'll see that there are differences in the internal plumbing which may, or may not, compromise your plans. If you really do need to replace the tank, I suspect using a petrol version would make the task far simpler.



TC

[Shuriken_57]

Originally Posted by T-Cut

Hello again Brahim, the outer plastic tank is basically the same for petrol and diesel systems, though there may be access points in one, diesel for example, that aren't used/blanked off for petrol models. I'm guessing I'm afraid. It's not a question that often comes up. You'll see that there are differences in the internal plumbing which may, or may not, compromise your plans. If you really do need to replace the tank, I suspect using a petrol version would make the task far simpler.



TC

Thanks you .
I think I have a lead on my fuel failure.
I noticed that the little tank on which the fuel pump rests has come loose from the tank.
Unfortunately, it is impossible to put it back together again.
I think it’s stuck to the bottom of the tank originally.
The vehicle does not start now.

[podge]

Hello guys,😀though Ihave not posted for months…even a year or two I am still a happy Tourer driver..second one now.However, reading through this long and excellent post.I too now have a “fuel cooler system issue”. The return system has sprung a slight leak where the fuel pipe connects to the top of the cooler.I have dropped the whole lot,replaced the pipe that goes from the top of the cooler to the restrictor body and fitted the correct clips.It still weeps fuel, enough to be visible after a short run.I am wondering what is causing the pressure to get past the connection? My initial thoughts are a failure of the bi metal valve? I have a good secondhand assembly on its way,I was thinking of swopping the whole lot over then taking mine apart to find the cause.The cooler it self does not appear to be leaking,it is that connection where fuel is seeping past the hose,I have even double clipped it.So any ideas would be great.Thanks Pete.