Peugeot intank pump - too much pressure?

[JohnDotCom]

I have queried the availability problem quoted with the new Single Pump WFX000350 with my "person" at XPart.
They Say no date as yet for when will be back in,
but not got any back orders or requests for them from dealers either.
I knew it was reliable, but it seems why stock something no one wants?

There is 8 shown in stock at various XPart dealers if anyone is stuck though.

[pondweed]

Originally Posted by efreeti

The 2.5 bar tank pump delivers 240 litres per hour (shown as 4 LPM) @ 12V according to fuel system data. *

well thats helpful, as it looks like the walbro pumps (quoted £70 posted) are 190 lph or 255 lph... so the higher one looks a better bet. But it still doesnt tell us about the later pump - is this in your fuel system data too??

I must admit, I'd still be tempted to use the tried and tested peugeot one at the moment, although presumably it must be less well made if the whole caboodle can be bought for £70 or £80 against just the pump for £70 from Walbro?

[James.uk]

Post your question on this site under "Peugeot" and I expect you will get more info from that end. One can nevr have enought information.

http://www.frenchcarforum.co.uk/forum/
.

[pondweed]

info from walbro -

190lph equates to 2.6 bar at 12V
255 lph equates to 3.4 bar at 12V

If we now effectively know that the rear pump is "supported" by the front pump clicking in and out to maintain pressure, and that the regulating valves do the stabilising of the system, which one would be better in theory? (The lph and bar readings are different to Efreetis MGR ones, so I' m head scratching!)

[crofts]

From following this issue right from the start it was stated that the output was higher but of several early ones changed no-one reported a problem (with the exception of where the underbonnet pump had already failed as a result of the extra load placed on it from a failed tank pump)
Also from the start there was the suggestion that the underbonnet pump could probably be dispensed with but to date I am not aware of any member trying it, again, probably on the basis of, 'why take the chance' for the moderate cost saving ( and of course the added benefit of the u/b pump keeping the car going in the event of the i/t pump failing...... an all too frequent occurence it would appear from the posts.

[efreeti]

Ok, after an hour of digging through loads of data I have come to the conclusion that the workshop manuals were written by about 300 different people, none of whom had ever met each other. The names they use to describe a particular component seems to change as you go through, making it difficult to work out exactly which bit of kit they are referring to.

However, I now know the following information which I didn't before...

1> The ECU needs to read at least 1.7 bar at the sensor on the fuel filter or it will start to cut throttle and engine speed to reduce the demand from the HP pump, avoiding potential damage.

2> The "Pressure Control Valve" limit is 22 bar. I am having trouble working out which valve this is. I think it is the maximum tolerance for the 2.5 bar pressure relief valve as it is too low for one of the HP system valves.

And now the interesting bit...

3> "The primary low-pressure pump draws fuel from the swirl pot and delivers it to a filter unit adapter mounted in the left hand section of the fuel tank. The adapter unit contains a pressure regulator which is calibrated to 3.6 bar, this will not open during normal operation of the system"

This is the only thing I have found which makes reference to any sort of upper limit on the pressure of the low pressure fuel system (other than the rather ambiguous "22 bar Pressure Control Valve limit") This 3.6 bar regulator doesn't show up on any of the LP system diagrams, it would probably only be shown on a diagram of the pump assembly itself, which I have yet to find, so this bit of descriptive from the engine operation description is all I have to go on.

It does seem to suggest though that even the 3.4 bar pump is well within the limits of normal operation. The system needs between 1.7 bar and 2.5 bar to operate. Anything between 2.5 bar and 3.6 bar is dealt with by the 2.5 bar pressure relief valve. Anything over that is dealt with by the in tank pressure regulator. I wonder if any alterations were made to the assembly itself when they swapped over to the single pump system?

We seem to be making some progress slowly. It would be good to get this information stored somewhere so we don't have to go through it all again in 12 months time!

[Roverron]

Originally Posted by efreeti

Ok, after an hour of digging through loads of data I have come to the conclusion that the workshop manuals were written by about 300 different people, none of whom had ever met each other. The names they use to describe a particular component seems to change as you go through, making it difficult to work out exactly which bit of kit they are referring to.

However, I now know the following information which I didn't before...

1> The ECU needs to read at least 1.7 bar at the sensor on the fuel filter or it will start to cut throttle and engine speed to reduce the demand from the HP pump, avoiding potential damage.

2> The "Pressure Control Valve" limit is 22 bar. I am having trouble working out which valve this is. I think it is the maximum tolerance for the 2.5 bar pressure relief valve as it is too low for one of the HP system valves.

And now the interesting bit...

3> "The primary low-pressure pump draws fuel from the swirl pot and delivers it to a filter unit adapter mounted in the left hand section of the fuel tank. The adapter unit contains a pressure regulator which is calibrated to 3.6 bar, this will not open during normal operation of the system"

This is the only thing I have found which makes reference to any sort of upper limit on the pressure of the low pressure fuel system (other than the rather ambiguous "22 bar Pressure Control Valve limit") This 3.6 bar regulator doesn't show up on any of the LP system diagrams, it would probably only be shown on a diagram of the pump assembly itself, which I have yet to find, so this bit of descriptive from the engine operation description is all I have to go on.

It does seem to suggest though that even the 3.4 bar pump is well within the limits of normal operation. The system needs between 1.7 bar and 2.5 bar to operate. Anything between 2.5 bar and 3.6 bar is dealt with by the 2.5 bar pressure relief valve. Anything over that is dealt with by the in tank pressure regulator. I wonder if any alterations were made to the assembly itself when they swapped over to the single pump system?

We seem to be making some progress slowly. It would be good to get this information stored somewhere so we don't have to go through it all again in 12 months time!

I suppose its possible that too high a pressure at the low pressure sensor in the fuel filter housing could trigger the MIL. 2.6bar is about 4v so 3.4 bar would be into the fault code triggering region. You may therefore have to reduce the signal from the sensor with a couple of resistors if this becomes a problem.

Ron

[pondweed]

so we need to work out, on balance, whether it is better (less strain on system) to have more pumping power and potentially more relief valve use, or less and keeping within system bounds. And ascertain whether the needs of a TU3/synergy and improved breathing really demand anything more than the spec MGR provided?
I guess its not particularly good having a higher power pump with inadaquate pipework.
I've got a headache....

[davidm_uk]

Just to add a bit more information (or confusion), when I changed my in tank pump I followed an earlier post on here http://www.the75andztclub.co.uk/foru...ead.php?t=4512

Having removed the R75 pump assembly from the tank, and inspecting it to try and make sure I remembered where all the bits went, I was a bit confused that the pump itself wasn't directly connected to either of the outlets at the top of the assembly (where the two external fuel lines connect). You can just about make this out from this diagram (borrowed from that earlier post - acknowledgements to efteeti):



You can see that the pipe from the top of the pump motor goes off to the plastic "arm thingy" (d2) that sits in the tray in the bottom of the tank. One pipe from the top of the pump housing runs down the side of the pump motor to what might be a pressure valve, and then dangles in the fuel. The other pipe from the top of the pump housing runs down behind the pump motor and again just dangles in the fuel (you can just see the end of the black pipe to the right of the a2 label that efreeti has annotated the picture with).

So - the pump motor doesn't seem to directly connect to either of the two external fuel pipes. Quite what the plumbing circuitry in the "arm thingy" is I didn't bother to work out (wish I had now, it's been bugging me ever since). The trailing pipe (c2) from that thingy connects to a block inside the tank and from there a pipe goes over to the opposite side of the tank. I never looked to see what external connections there were to the LH side of the tank.

Anyway, upshot is I'm pretty sure that it's not a straightforward case of - pump dangles in fuel, sucks it up, squirts it out the top to the external pipe going off to the engine.

A plumbing circuit diagram would be a great help (to me anyway)!

David

[pondweed]

http://forums.mg-rover.org/showthread.php?t=123849 see Ron's post 6 - does this help here?

and also from MattL on org in 2006 - worth following up. (talking about post 2004 one pump set up)
"Looks alot like the later Freelander setup. On Freelander they deleted pump in tank (03 or 04) and fitted a pump module in the rear wheelarch which included pump, sediment tank and filter. Im guessing they used a similar approach on the later 75 ZTs. Freelander also had the additional sensor in the hose."

from Sterling on org (a 2 pump car)
"So my dealer changed the pump, and thougt he could take the pump of a new 2005 CDTi, which stood in the showroom. But this pump didn´t fit, even thoug my MG ZT was als a 2005 model. Indeed it is so, that there are 2 pumps till VIN 5D32300, and from VIN 5D332301 only one pump! And the new pump isn´t the same pump as the old one, because the connections aren´t the same."

http://forums.mg-rover.org/showthrea...=151829&page=2 (post 24) has three pics of the later ONE pump set up wiring and mounting into the tank! Can anyone get them onto here for posterity?