2000 V70R - AWD Fuel pump and ejector (Fuel pump 9470674)

[Maestrours]

Hello everybody...
Always on the same issue, I convinced myself to give it a good look. I put the gas tank down as Robert DIY teach us, and give a look a the pump, and the venturi-pump on LHS. This one is ok, nno doubt at all.

As a reminder, my issue is that at half tank, I run out of gas. left part of the tank does not go on the right part.

For the electric pump, it has been replaced by previous owner by this one:

https://www.piecesautos2607.fr/pompe-de ... turbo.html

Immediatly after installing it, the issue began.
i just take a look at the pump, i'm not sure anything can be charged. Seals seems ok, it works fine until Right gas tank is empty.

but, as I look for a replacement pump as I just don't know where to search now except a faulty pump (lack of pressure/ gph?) I just cannot understand all the pump I can see;

I can see 44psi, 56 psi, 65 psi... 100, 120, 180l/H...

i know that a Walbro GRJ235 is ok, but if I search this can have different reative pumps, with different PSI.. As the fuel pressure regulator is set at 44psi, how many PSI do I need to activate the venturi-pump on the left side? I'm asking myself about an insufficient pressure that cause this issue as the pump was sold for 56psi;

What exact pump can I fit in my 00' XC? is the model in previous link ok ?

I'm just totally lost in this, my car doesnt move since 1year and if I don't find how to repair this issue, I'm afraid I'll have to push it to the junkyard...Too many time lost without any solutions for the moment.

Thanks by advance to those who'll help me!

[abscate]

The early AWD system uses the excess pressure from the fuel pressure regulator to “ drive “ the ejector pump.

I will link to a picture.

If some connected the new pump without knowledge, half of the fuel won’t be usable.

[Maestrours]

The early AWD system uses the excess pressure from the fuel pressure regulator to “ drive “ the ejector pump.

I will link to a picture.

If some connected the new pump without knowledge, half of the fuel won’t be usable.

Yes that I know. I replaced yesterday the left sender, just to be sure it isn't this piece but when I gave it a look, this piece cannot fail it is a very simple conception.

But as the issue appeared after electric pump change, I can assume that it is located around this area.
Do you know what is the pressure of OEM pump ? Cannot find this data.
Pressure after regulator is 3bar, but I guess that the output pressure of the pump must be higher to drain the fuel from lhs to rhs ?

[scot850]

There is a fuel pressure regulator that supplies the return pressure to push the fuel from the LH to the RH tank. It sounds to me like you may not be getting that pressure to the LH tank. Like you said, if you replaced the LH ejector unit, then it is unlikely to be that.
The only options then are the regulator is bad or there is a blockage for some reason in the return pipe to the ejector or from the ejector to the new pump.

Neil.

[Maestrours]

Even with vida I cannot find the FPR reference... Does someone know it ? I guess it is NLP but maybe there is another reference I can get.

[scot850]

The fuel pressure regulator is part of the main fuel line front to back. It sits on top of the fuel tank on the RHS approximately near the rear wheel.

Fuel lines and FPR

2000 V70R Fuel tank 002.JPG (265.05 KiB) Viewed 386 times

In the picture above you can see the fuel lines running up the side of the fuel tank. This is the RHS of the tank. The FPR is the small silver cylinder toward the top of the picture and near the rear of the tank. The thick black pipe behind it is the fuel filler pipe. The FPR sits just inwards of the RR shock tower.

FPR on tank

Sub-frame out of 2000 V70R 005.JPG (284.79 KiB) Viewed 386 times

Again, you can see in the above picture the FPR cylinder just forward and inboard of the rear shock tower.

FPR

Fuel and emissions line routing 2000 V70R 006.JPG (315.51 KiB) Viewed 386 times

The FPR is a weird item. It is sandwiched onto a plastic rectangle. Under the body of the FPR and inside the plastic part there is a valve. From what I can figure out is the lower valve controls the fuel pressure based on the return pressure to the fuel tank running through the valve.

Bad news. The FPR is NLA and was only sold as part of the NLA fuel line.

Neil.

[abscate]

The FPR on the late 1998-on P80s line, including the AWD models is no longer controlled by manifold vacuum, but regulates the fuel pressure to 42 psi relative to atmospheric.

System description here. I proudly thought I brought this knowledge to MVS but it was found here in 2010

The Motronic 4.4 changes to the NA included a new "tailored return lacking fuel system". Here is the description:

Last year the Return Lacking Fuel System
(RLFS) was introduced on the B5254S with
Motronic 4.4. The fuel pressure regulator is
connected so that fuel pressure is retained at a
constant level (300 kPa (43.5 psi)) above the
pressure in the EVAP line to the fuel tank (≈
atmospheric pressure).

This gives an accurate enough control with
today's fast processors in the engine control
module (ECM) of a naturally aspirated engine.
On a turbocharged engine on the other hand
with larger pressure variations the intake
manifold, this does not provide enough
accuracy.

The advantage with not having a fuel return
line from the fuel rail is that the engine does
not heat the fuel, the temperature in the fuel
tank remains low and the amount of
evaporated fuel is reduced.

”Three way unit”
The fuel flow is controlled as before via a three
way unit which is integrated with the fuel
pressure regulator. The following are
connected to the three way unit:
The fuel line from the fuel tank.
The fuel line to the fuel rail.
The return line to the fuel tank.

[scot850]

Does this include the 99- cars where the fuel pressure is 50 psi + ? (Mine was measured by the dealer with the new fuel pump and lines at just below 60 psi).

Neil.

[abscate]

Does this include the 99- cars where the fuel pressure is 50 psi + ? (Mine was measured by the dealer with the new fuel pump and lines at just below 60 psi).

Neil.

Yes. The fuel pump spec is for the take off right after the pump, not the fuel rail

That pressure should be 42 psi.

[Maestrours]

Thanks a lot for this precious informations (btw sorry for my english)
My car is a 2000xc but the fpr is still connected to the evap line (btw there is no canister on the car anymore... Thanks to previous owner).
Supposing my fpr is dead... What would you recommend to me ?

And an dditionnal question quite complicated but i'm struggling to find a good testing méthod:

-How would you test the correct functionning of the left-to right fuel tank system ?

Since I changed my left sender, and replaced a seal on right sender, i tried this: put a valve on the fuel line just before the injectors; set on the pump. After some seconds I hear the fpr whinning (is it normal) and few more seconds and I hear fuel passing by the left gas tank line.
If I slightly open the valve (pressure always >43psi I have a small income of fuel, always till gas tank empty. If i open totally the valve, after some second there is no more fuel coming.

Am I correct to say that it is now working ? How can I be sure of that ? What is the gph rate of the fuel at 3 bars ?