Hdi Lift Pump Upgrade (Pics/Tips inside)

[mcglynn]

Well like I say I bit the bullet and went for a new lift pump.

Mine was showing signs of failing having cut out on me in roundabouts etc, leaving me in some hairy situations.

Bought the APS 255 walbro copy off ebay, £49.95.



I soon found out the probable cause of my problems..

Take out the rear drivers side seat and lift the circlular flap thats pre cut in the floor closest to drivers side and you will see a black plastic cover (Its quite stiff and needs a screwdriver to lever it off).
Once thats off you need to remove the two high pressure fuel line fittings (they only fit on the correct pipe for redoing them)
Remove the ring holding the pump down (hit it anti clockwise with a screwdriver to get it turning) and once off your pump should lift out.
Be wary of the fuel level float in order not to damage it or the wiring.

Once out it will look like so;



Flip the two small arrows on either side of the white plastic fuel level sender and slide it down/off.

Then unclip the prong at the right, lifting it over the catch with a screwdriver underneath it and the top of your pump housing will come off. (Watch the spring & small yellow collar they like to go walkabouts)

Pump housing will now be in two bits.

Remove the power cables clip from the pump and remove the blue hard plastic fuel piping (may need a stanley blade/snips)

Remove the middle of the housing. There are three snibs on the outer casing. When all three are released you can lift the middle out and access the in tank filter.

With some persuasion the pump will come out of this middle housing. I put three flat headed screwdrivers around it to hold out the securing prongs and pull on the pump upwards with vice grips.

On the bottom you will see the filter/strainer. Well my housing was full of filth and so was the strainer. Horrible mess, probably 14/15 years worth of questionable quality diesel has gons through it.









Replace the old pump with your new pump, which in my case needed the sound proofing fitting to make it a snug fit in the housing.

The in tank filter was an issue for me, as the supplied one wasnt going to fit. No chance. The standard one wouldn't fit onto my APS pump as the bottom inlets are so different in size.





This is where I cut a spare bit off the supplied fuel pipe and where it goes.
The outer diameter on the pipe was enough to take up the extra on the standard strainer.. (cleaned ofc, I used an airline although diesel would probably help clean it).



Squeeze the other end of the fuel pipe onto the inlet of the new pump and align it the corrwct direction, so that if will fit back into the main housing, then slide in your middle housing. Check that the filter looks flat/fitted correctly and then secure the snibs at the side.

Next you should cut the stabdard plug off the wire on the top part of the housing, get some electrical butt connectors (blue type) and connect up your standard plugs wiring to the new plug supplied.

Brown into black and red into red.



Connect your fuel hose to the top and tighten the jubilee (supplied).

Check everything is clean and tidy, connect the electrical connector to the top of the pump and make sure your fuel senders wires arent tangled around anything, as they won't be long enough to clip it back on as I found out the hard way.

Then slide your supplied fuel pipe over the outlet on the APS pump, tighten the jubilee and pop the lid back on.

The final step is yo connect your fuel sender, again it will only fit one way which you will see.



Go and refit it to the car the opposite of to how you took it off, ensuring its all connected and the seal is in the correct way. Tighten the plastic ring, again I done this with a screwdriver, hitting the ring clockwise.

Then you can enjoy the new lift pump!

Hoping this has cured any cutting out issues for me

[jammapic]

Well done.

Hope my advice helped a bit, wahey for big lift pumps! Worked wonders on my stage 3!

JP

[Poodle]

Thanks for the write-up, could we get this moved to the guide section?

[mcglynn]

Cheers guys, will report how it goes.

Cars revving/pulling happily no problema thus far. Touch woood

[Dum-Dum]

Nice guide mate.

[lolsteve]

Interesting , wonder if this will be the start for a new wave of hdi modifications

[mcglynn]

Im just setting all the stepping stones in for a big blower matey!

[L.J]

Just out of interest why go for one of these and not the standard one? Are these an upgrade?

[mcglynn]

Dont think the standard one has them same flow/high pressure output.

[Poodle]

Yup, that's why. At the moment it's an experimental mod, no-one has actually run one at a different pressure yet afaik, so the benefits are still questionable. Be good if somebody fancied doing some definitive testing for us...

[mcglynn]

How would you alter the pressure output? Surely its proportional to the flow.

For instance, it would be running maximum pressure until a certain threshold where flow demand is more and the pressure of the pump is less to accomodate this, if ive got it right in my head.

It basically lessens the strain on the HP pump as its not 'drawing' fuel at high rpms and is being fed it, so can focus on its sole purpose of pressuring the fuel instead of drawing & pressurising it.

[Jesskendall123]

Nice Guide dude

[Poodle]

On the walbro pumps you can alter the flow on the pump, as I understand it. Flow does change with the pressure, but the top spec high pressure pump flows over 200lph at 80psi, which is way more than we'll ever need, even at 5.5k. That way it'll have full pressure all the way through the range, no worries about drop off, i'd be more concerned about the fuel return line being man enough lol.

That's the theory, i'm looking forward to seeing it tested.

[mcglynn]

Ahh, well as far as I can see theres no adjustment on this one im afraid :/

[jammapic]

Poodle, you could adjust it on my old walbro pump.

Eoghan, do you not have the little inset screw head?

JP

[mcglynn]

Where abouts is it? I didnt see it on mine tbh, I will have a look again though..

[Dum-Dum]

Gotta say I didn't realise the walbros were adjustable. Surely the adjustment in pressure is done by the regulator. Poodle you know im really keen to re pipe the whole LP fuel system and add a decent front mounted fuel cooler. I wish it was cheaper to data log the current LP pressure and temp.

[mcglynn]

I looked on my pump and contacted the seller. There is no adjustment, it simply flows at maximum capability with respect to input voltage and current draw.

so the piping will ultimately determine the flow rate and it will flow as hard as thoise pipes will let it, the pressure etc isnt really a bother anyway i would say, so long as it can keep the fulter housing topped up then it shouldnt cause an issue.

Mine is pumping decent amounts of fuel now with no pump problems it seems.

[Poodle]

The regulator is post hp pump, so that won't regulate anything on the low-pressure side. Yeah, i'd like to do the same myself, Chris, bigger fish right now though.

It depends what the limiting factor is, Mcglynn, for all we know the filter housing could be the main restriction. Until someone does some definitive testing we can't know the effect the lp circuit pressure has on the rest of the fueling system, there are just too many variables involved.

[mcglynn]

Yeah I know it wont regulate, thats pretty self explanitory as the pump has a regulator on it lol.

I was meaning to say the lp can push the fuel to the filter housing, keep it topped up & allow the hp pump to be well fed.

The hole in the pump housing is large enough to allow a good amount of fuel in and quickly as well as having a design that is a one way valve.

In laymans terms, if the fuel level is higher than the bottom of the filter, then there will be fuel in the housing and I can't see it drying that out too quickly tbh. My 'feed filter' touches the bottom of this so it's as low as It will go in the tank. I didnt get seeing how low the filter was with the original pump although I assume it was a little higher.

It will always present a problem with harsh turns and hard acceleration as the fuel will be at the wrong side of the tank and the bowl would soon empty itself out with the engine flowing big fuel quanitities in a higher state if tune, simple solution is to keep the fuel above quarter tank when driivng hard.

Not sure what the next step is but the lift pump I fitted costs roughly the same as a second hand one off here, maybe a slight increase in price (~£50) as well as being easily fitted, so id definately recommend doing it.

[Poodle]

That part about the reg was in response to Chris, bud.

Absolutely, but how do you know just keeping the filter housing topped up is enough? Have you flow-tested a filter housing with filter to see just when it becomes a restriction? Not having a go, just pointing out that until we come across better information or somebody with the means tests these items, we can't know.

The ecu won't wait for the system to run dry before it cuts out, it just has to see a significant difference between requested and actual iq - as such just keeping the fuel filter wet may not be enough, the system may require a certain pressure pre-hp pump. By the same token, a constant supply might be all that's required; although that seems unlikely, else why would they put a 3.2bar pump in as standard when there are much cheaper units that run at lower pressure... But, we can't know for sure before it's all tested.

Indeed, exactly as i've said before. Obviously it's not exactly a proper solution, but if there's no plan to go beyond stage 2 then it's all that's required.

Even the walbro pumps are cheaper than the standard items, iirc peugeot charge about £90 for a genuine lift pump. I think it should be a worthwhile mod, but again, until it's tested properly we can't know whether it's an improvement or not.

[Ruan]

The HP pump in a CP1 system requires pressurised fuel supplied to it - it has essentially no suction on the pump - soon as it starts dropping the pressure on the inlet side to the HP pump, it'll struggle to make pressure. That's why the CP1s are SO sensitive to the LP pump failing/going round a corner hard.

The problem is also exacerbated by the fact that the CP1 pump will move it's full amount of fuel into the inlet side of the regulator at all times. This is a problem with the early CP1 design - it means that it heats the fuel a lot, it's pumping closer to all of it's fuel through the body of the pump to high pressure, but then mostly bled off by the regulator.

That ALSO means that it's moving close to it's full quantity all the time, so it gets through fuel at a rate of knots - combine that with the fact that the LP pump often can't suck fuel up when you NAIL it round a corner, it's moving a lot of fuel, so air gets picked up easily, soon as a bit of air gets picked up, it then drops the pressure in the fuel filter housing, therefore the pump starts to starve of fuel, instantly dropping the rail pressure.

This is why I reckon these should be accompanied with a swirl pot in the engine bay - you only remove one problem by putting in a bigger lift pump, that's the supply issue when you stamp on the throttle and the rail pressure goes up - nail it round a corner or continuously demand big injections, you're still likely to struggle for fuel after the filter housing.

IMHO you should have:

Code:

--------------------------------------|<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<|
TANK>>>>>>lift pump>>>>>>>>>>>>> SWIRL POT >>>>>>>>>>>lift pump>>>>>>>>HP CR PUMP>REGULATOR>>>>RAIL>>>INJECTORS
|<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<|<<<<<<<<<<<<<<<<<<<<fuel cooler<<<<<<<<<<<<<<<<<|

Very poor diagram I know... But hopefully that explains what I mean...

Lift pump from the tank, into the swirl pot, another lift pump feeding fuel straight into the inlet of the CR pump, regulator for the CR pump bleeds off through a fuel cooler back to the swirl pot (or back to the tank, whichever you prefer - tank may be better to prevent any restriction on the return side) injectors bleed back off into the swirl pot (or tank..) also. You can change that round if you find you're not getting enough cooling of the fuel as an average, you want it slightly warmed which mixing it into the swirl pot should do nicely, if you cooled it on the inlet the HP pump I think you'd end up overcooling it and creating more ignition delay.

For the record, this is what the CP3 pump changed, the CP3 pump has it's own 75psi regulated gear pump internally, so you pump fuel to the inlet to the gear pump, then the pump is pressurised by it's own "feeder" pump internally and regulated before the HP pump to prevent fuel overpumping/heating.

[mcglynn]

Some VERY interesting reading there as usual Ruan!

And my point exactly poodle, it doesnt 'solve' the issue but its surely better than buying a second hand 'low mileage' lift pump for around £40. If the car was going on track under constant strenuous conditions id maybe consider changing the fuel system to an extreme but for me this does just fine. No complaints thus far.

[Scottp123]

Did you ever have any problems mate I bought one about 6 months ago and it never worked but could hear it priming I was thinking it could be the thicker hose not compressing the spring not 100% on how it works feel free to call me a dumbass but any help would he much appreciated I threw it in the shed and that's where it stayed but putting a stage 2 map on next week and stumbled across it really wanna get it in

[mcglynn]

No didnt have any problems bud.

Shouldn't be an issue with the hose its supplied with as it will flow more than enough to fill it up.

I did cut the hose really short so that the pump housing would click into itself.

Worst thing was ensuring the pump itself sat low enough in the housing so it was lifting fuel right from the bottom.