Appreciate your input.

No specs listed on-site - the 160hp 2.8 CRD has way less than half the requirements of the stock DMax 300hp 6.6 CRD, much less the requirements of the 600-1200hp runners.

Liberty fuel tank is ~half the size of the DMax tank - smaller container = more foam - increased fuel-return = increased foam

Specs would be good for comparison - what do you think?

_________________
'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

We just returned from our weekend camping trip. Recap, on previous trips almost any grade causea down shift or two into 4rd at 50mph and around 3k+ rpms. Last week I used the 40106 pump I got from nappa with no bypass/bleeder and reported the good results I got. Before leaving on Friday I checked for air in the fuel head and there was none Our trip was about 200 miles pulling our 3000# TT WITHOUT pushing the OD off button. The crd did not downshift at all going up grades. They were gentler then past trips but I notice no struggling at all. It still runs fantastic without the bleeder

_________________
Atlantic Blue 06 CRD Limited (his)
Joined by a 2000 XJ Classic (hers)

Jeep engineer should be lined up at the firing squad...........

_________________
2006 Black Jeep Liberty CRD Limited
K&N, Samco Hoses, Michelin 245/70-16 LTX A/T2, Fumoto F-102, V-Force Muffler, Mopar, Hitch, Trailer Wiring, Skid Plates, Slush Mats, Rear Shelf, Predator Stage 1, Transgo, ORM & CodeReader, Facet 40109 Pump
"IT'S A DIESEL THING, YOU WOULDN'T UNDERSTAND"
Certified Services Auto & Truck Repair

[quote="BlackLibertyCRDJeep engineer should be lined up at the firing squad........... [/quote]

The bean counters are my guess

_________________
Atlantic Blue 06 CRD Limited (his)
Joined by a 2000 XJ Classic (hers)

How many miles do you have on your installation, Blacklib - most excellent setup, btw..........

Suggestion - possibly you and retmil46 could occasionally post your mileage accrual without incidental hiccup or burp - he has the hi-flow pump, you have a low-flow pump with bypass - if no problems, then it's Katy, bar the door!

Concern, of course, is Bosch C(P)3 warranty and MrMopar's input - which is Bosch's repetitive stance on the IP - however, this IP is not identical to the one in the DMaxx, so there is reason for some concern.

_________________
'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

Concern, of course, is Bosch C(P)3 warranty and MrMopar's input - which is Bosch's repetitive stance on the IP - however, this IP is not identical to the one in the DMaxx, so there is reason for some concern.[/quote]

"Ranger1 has monitored fuel rail pressures with an Eqqus scan tool - no change between running with or without a lift pump"
(From Page 4, this thread)

This is good news!

I wonder if Bosch stands to foot the bill if they end up putting a official lift pump on That would be a good reason for their stance

_________________
Atlantic Blue 06 CRD Limited (his)
Joined by a 2000 XJ Classic (hers)

I have a couple of tanks on the setup. Fuel mileage seems to be up, maybe it seems to take less effort to get and keep going. No hiccups or burps, runs perfect. Three weeks from now I be going cross country pulling 3,000 lb trailer. That will be a real test.

_________________
2006 Black Jeep Liberty CRD Limited
K&N, Samco Hoses, Michelin 245/70-16 LTX A/T2, Fumoto F-102, V-Force Muffler, Mopar, Hitch, Trailer Wiring, Skid Plates, Slush Mats, Rear Shelf, Predator Stage 1, Transgo, ORM & CodeReader, Facet 40109 Pump
"IT'S A DIESEL THING, YOU WOULDN'T UNDERSTAND"
Certified Services Auto & Truck Repair

I now have run 4k using the holly blue lift pump. I ran hard for 3k up to canada burning veggy blend 50%-80% carrying a very heavy load. The little tractor loves it, not even one hiccup to report. I have monitored the rail pressure and there is absolutely no variation with or without the pump. Mileage has gone up, crank time during startup has gone down and there is 0 air in the filter head. I installed the pump without the pressure regulator that came with it. It runs at 14 Lbs(anyone interested in a pressure regulator 20$) I think however that I am going to swap the holly with the duramax pump from my F250 because the piston pump is much quieter than the holly (sounds like a jet fighter) and I need the higher flow in my ford anyway. Thanks go to MrMopar for all his help in other matters but he was slightly off the mark on the lift pump feasibility issue. I think it has been proven to work perfectly.

_________________
Manure green 2005 CRD sport4x4, GDE Hot tune, Cat Gut, OE skids, Draw tight hitch, Duramax lift pump, 160K on multiple varieties of fuel, XM radio, Escort live with Redline, fog light mod, GPS, Icom IC7000 all band radio call sign KC9QPF, Grabber AT2s on Soft 8s, FIA grill blanket.

Thanks - I had read that, Banknote

The CP3 gearotor lift pump is capable of drawing ~20"HG, which is equiv of 10psi below Baro, which would put the surface pressure intank at Baro - 10psi = ~5psia - intank vacuum relieves surface tension of the fuel allowing even the smallest aeration bubbles to outgas, so the tank cap has a 2" vacuum relief valve - also has a 1psi pressure relief valve - pressure, on the other hand, would compress the aerated fuel such that the bubbles travel with the fuel until pressure is relieved, which ain't gonna happen as it enters the IP - hmmmm - would involve a slight increment in fuel volume, but more air in cylinder would increase burn..............ummm, neb' mind that, eh?

So, from all the info I've so far gleaned from the 'net, which ain't much, and from the FSM -
- during CRANK, gearotor-pumped fuel between 0 and 44psi, based on inlet fuel at LESS THAN Baro pressure on the inlet, is fed to the Cascade Control Valve passages to the CP3 only for lubrication - also bleeds air and excess fuel back to the tank
- during CRANK and run, as gearotor builds fuel pressure above 44psi, the COV opens another passage for lubrication, holding that up to 73psi - this is max housing pressure feed to the hi-pressure pump thru the Fuel Quantity Valve
- when running, any pressure over 73psi is returned back to the inlet and excess goes thru the overflow valve back to the tank
- the FQV feeds fuel to the hi-press pump based on rail pressure - excess is trimmed at the low pressure side to prevent excess hot fuel return to the tank via injector overflow

Now - if a pump has Barometric pressure on the inlet and is set for 5psi max, it will pump 5psi - as the inlet pressure drops, as from a dirty filter, so will the outlet pressure - it will always be 5psi above it's inlet pressure level.

Which means that if you add another pump ahead of the inlet, set for, say 10psi, the output of the original, or secondary, pump will then be 15psi - this follows right on up the scale - primary 20psi, secondary 25psi, etc - any number of gasser (patooie!) injection systems employ the concept, as do the big boys on the turbo circuits - stack turbos in series for 60, 75, 150psi Boost levels.

Point of all this being -
- vacuum in the tank of a Diesel fuel system is good, as it de-aerates the fuel - I'm thinking that's part of the design of the CP3 system
- pressure in the tank is not good as it compresses the aerated bubbles, then sends them on into the IP - the gearotor overflow system supposedly sends them back to the tank
- CAUTION IS REQUIRED when installing an auxilliary lift pump, as high inlet pressure on the gearotor pump offsets the function of the COV, with possible damage to the internal CP3 bearings
- same goes for aux lift pump volume - obviously you don't need a 100gph pump supplying the gearotor, as that pump will be very inefficient at 3gph, which is 20mpg at 60mph - and the excess volume capability could likely churn up the fuel till it looked like meringue on a lemon pie

Alternately, the filter manager head could be reworked with an internal tube extension, such that the fuel outlet pickup point is located further down in the flter, below any air pocket, thus satisfying warranty requirements by allowing continued useage without a lift pump.

So, without any further cautionary input from MrMopar, looks like a carefully considered auxilliary lift pump system would only hurt your warranty - remember: bigger ain't better, here..........................

_________________
'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

Also, thanks for the input, guys, while I was 'composing' my thoughts

FYI -

The increased slow-start and subsequent improved starting with the aux lift pump is a no-brainer - as fuel inlet pressure to the CP3 gearotor drops, so does housing pressure, causing a delay in fuel supply to the FQV - this delays injection while housing pressure rises, so you get more cranking revs B4 lift-off

Install the lift pump, which pre-runs to prime the CP3 during WTS = instantaneous housing pressure rise when the key is turned to START and voila! = recovered easy starting

Factory-installed aux lift pump circuitry could be a military option or EURO option for Sahara or\and deep-cold service

_________________
'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

Here is what I think...

Having only been reading about this stuff and not tried any of it.
In stock form with STOCK fuel filter, everything SHOULD be fine.
But, if you put in a better fuel filter (i.e. CAT 2 micron) the added
restriction caused by better filtration puts too much strain on the
suction pump. It then starts to suck air and get starved for fuel.

So, in this instance, adding a lift pump COULD help relieve the
strain on the suction pump. Adding a bypass line after the filter
will help eliminate any excess pressure from the lift pump.

They way I see it, theortically, the total net pressure on suction
side SHOULD only be 1-2 psi at idle. As fuel demand increases,
this could drop to 0 psi. Provided of course that a proper diameter
orifice is used for the bypass and that the lift pump provides a
consistent, steady flow of fuel.

What do ya think?

_________________
U.S. Army Retired

Your thinking leaves out one possibility Many of us have had the 50 MPH shudder from the very beginning of our CRD ownership. It was then thought to be the torque converter but guess what, it turns out to be air in the filter My 06 shuddered 1/4 of a mile from the dealer the day I bought it I have never added a cat filter and only last week added the lift pump. My experience driving, owning and wrenching diesels over the last 30 years told me my crd ran like crap Some people here have no prior diesel experience to draw on eather as a driver, owner or wrencher and just don't know how a diesel should run and don't know of what they speak Then go on to say we don't know what we're doing and to trust the engineers to do a good job and to trust dealers that have little or no experience to fix these things. All I ever get is "could not duplicate" for a vehicle I bought new and paid good money for:!:

This is what I think

Joe

_________________
Atlantic Blue 06 CRD Limited (his)
Joined by a 2000 XJ Classic (hers)

gmctd:

I'm barely an amatuer at this, and I thought we had a permanent fix here, but I like your delving into why we should beware of unintended concequences. The Lift pump is still sucking a vacuum from the fuel tank(at a much shorter length). It sounds like your concerned about the cascade process being altered as the pressure is increased from the lift pump. It seems like the cp3 will still get proper lubrication and possibly get to the lubrication step earlier. But it is the return step of the cascade you seem to be pointing out. Higher pressure in each step of the cascade ends into higher pressure into the tank. THis is where the air is not allowed to seperate because its pressurized vs. the vacuum allowing air to seperate. Since you didn't mention the lift pump still pulling a vacuum do you feel its not enough compared to the increased pressure from cascade? Am I following you?

If I am following you, isn't there a relief vavle in the tank that keeps it from pressurizing?

Thanks for your input.
Josh

Both are valid points, imo - also, have never experienced the starvation symptoms on any of my Diesels - currently have GMC, Dodge and Kubota, the Jeep makes 4 - but am familiar with the complaint, having been a diesel forum member since back in ought zero - didn't have internet access prior to that, nor were there many Diesel-specific forums.

The gearotor will pull 20" at higher rpm, so intense filter restriction may cause cavitation - the problem may also be the heighth of the filter above the source and the target - makes a good air-trap, as in any plumbing system, and fuel may be siphoning back to the tank from slight leakage after long use - one problem with a draw-type system is finding leaks - fuel is denser than air, so an air leak that would allow siphon-back would show no wet spots - I think it would help to put the filter\manager down on the frame rail, with no aux lift pump, where tank fuel would siphon to the filter - would that satisfy warranty over the next 50kmi?

I'm also now thinking a flow-thru 5psi lift pump, without external bypass, will cause no ill effects to CP3 operation - 30psi may be pushing it, not knowing the specs on the FQV, as that would put housing pressure over 100psig

Also, one of the solid-state solenoid shuttle types appear to be best choice for stock, non-racing use, because they shut down and the shuttle stops as pressure head is reached - they won't thrash the fuel into foam.

They're running aux lp's over on the DMax forums with the CP3 with no apparent problems - CP3 indicates the # of pumping plungers in the series - the numbers following the dash point to the spec, but DMax IP is not identical this one

The aux lift pump appears to be practically safe with no bypass if you limit pressure to below 10psi, preferably 5psi, impo

I have a couple things to try that may resolve the issue for those not wishing to install an aux pump

This next weekend we have scheduled for a planned F37 failure that will require Suncoast intervention and resolution - I'm pumped!

_________________
'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

You can't pressurize the fuel tank as it is vented. It isn't like a gas fuel tank, that is why you don't hear a "whooosh" when you take off the cap.

_________________
Dave

'06 CRD Limited, Lt. Khaki, MOPAR Slush Mats/Skids, DrawTite Front Hitch, Mag Lite, Yakima Bars, Thule Bike Rack, Fumoto, ORM, 245/70 Revo 2

Wish list: Lift, Boulder Bars, Something Bigger in the Front and Back, More Lights

That is correct, Josh - and the tank cap is vented for both vacuum and pressure at 2"HG, which is 1psi - vacuum, where draw meets demand, and pressure, where demand is less than draw, and return is hot.

That means the tank can always be pressurized, but never more than 1psi above Baro - it can also always be vacuumized, but never more than 1psi below Baro - a great whoooosh indicates volume of equalization, not high pressure - unless the cap is fnorked from intense offroad splashing and sloshing thru muddy ambience

Vacuum also results when warm fuel is pumped from ground tanks into vehicle tanks in cold temperature - and when hot return-fuel is returned to the cold tank

Pressure results when warm fuel is pumped from cool ground tanks into vehicle tanks at warm temperature, and when hot return-fuel is returned to the warm tank.

Pressure, when pumps are cascaded.

This will probably be a stretch for you guys recently new to Diesels, but Diesel fuel foams as easily as good on-tap beer - you won't see it because the Jeep has a newly designed anti-foam tank filler - that doesn't mean the fuel is not foaming, just that you won't see it in the filler neck , where the venturi effect is used to disperse the bbbbles

My Dodge and GMC both are foamy filler type - in summer it's a real chore to fill the tanks, waiting for the foam to settle out, pump some more, wait, pump, wait, etc - winter is better because cold fuel foams much less - also, foaming is reduced if the additives are poured in prior to filling.

Excessive return-fuel causes foaming, and hot fuel aggravates that, and so must be taken into consideration along with increased pressure when stacking pumps

Driving, with associated bouncing, dipping, jostling, sloshing and splashing, causes in-tank foaming

Maintaining a slight vacuum, rather than pressure, on the tank is likely why, imo, Bosh designed such a powerful lift pump in the CP3 - the pump manages return-fuel pressure and return-fuel temps, via the fuel temp sensor in the fuel manager head, to ensure very low-aerated fuel reaches the IP - 'course, imo, they never planned on Jeep mounting the fuel manager so high in the system

I'm thinking the aux lift pump can be a permanent fix - success of any modification is measured by increased driveability and customer satisfaction - and, getting it past MrMoservice, the warranty cops, and the smog cops

_________________
'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

gmctd,

It isn't just the cap. The tank also has an overflow/vent to the tank seperate from the filler tube.

I have been filling diesel fuel tanks on Cat D2, D4, IH TD9, swathers, Case backhoes, 55 gal drums, 5 gal Jerry cans and lotrs of other things for about 50 years. Understand foam well.

_________________
Dave

'06 CRD Limited, Lt. Khaki, MOPAR Slush Mats/Skids, DrawTite Front Hitch, Mag Lite, Yakima Bars, Thule Bike Rack, Fumoto, ORM, 245/70 Revo 2

Wish list: Lift, Boulder Bars, Something Bigger in the Front and Back, More Lights

Thanks for the input, 'catcher - takes experience to recognize it, so I figgered some of you guys had prior experience - for you guys that already know all this stuff, just talk amongst yourselves - I'm playing to the 'noobs' where this may be a first dip into the Diesel world with this little mule - I'm offering the other side of the story, or the rest of the story, usually ignored, so they will have enuff information to take care of this stinky, noisy object of their (and our) desires.

It's only in the last decade that mfrs realized the value of lightly vacuuming the Diesel fuel tank - most gasser-folk and old Diesel hands are rather argumentive about that at first, because vacuum can't be good for the fuel pump, yada yada yada - fact is, most of 'em bust right out and start drilling holes in the fuel cap (also referring to it as a gas-cap) - mob-mentality is a strange thing to observe

Sorta like that thing about Diesel fuel having the best efficiency at 120deg - that don't mean heat it up to that temp (would help in winter temps, tho) - it means don't let it get any hotter than that due to aeration - once it's in the IP attached to the engine it will be a lot warmer than that - put a cooler in the return line so it'll stay cooler thru the IP.

I rather suspect few newbies are like my son, who's been avidly searching for smaller turboDiesel after seeing Dad's big 3500 Dodge dooley totally disappear in a cloud of roiling tire smoke, as all 4 of those Michelin LX's began howling like a pack of wolves closing in for the kill - 'course, I wisely didn't tell him those Michelin tires were the hardest compound on the planet, and the only thing they wouldn't easily spin on is the spare tire rack under the bed of the truck - talk about hard and worthless - anything above 10% relative humidity and they're like driving on ice - my big Goodyears, much softer and excellent in rain, would've fared much better, but that big Dodge don't take no fer an answer.

So - lift pumps = good - pressure = good - vacuum = good - just don't get 'em all mixed up.....................

_________________
'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

I also have been filling diesel tanks for a year or twenty. The foam issue is really not a serious problem in relation to air in the fuel line. The only time foam is a nuisance is during filling the fuel tank. After about half a minute the foam dissipates and one can resume filling (incidentally I have only seen foam when filling with extremely high GPH flow pumps like those at some truckstop pumps, the auto diesel pumps which are the only ones which will fit into our CRD filling ports wont do it.). The return from the IP won't cause foam unless it is sucking a massive amount of air from a leak in which case our CP3 won't run anyway. The return line dumps the fuel at the bottom of the tank where there is no chance of picking up air. fuel sloshing in the tank doesn't cause foam, just look in the transfer tank of a pickup after some serious bumping offroad to verify. The very slight vacuum on some modern diesels is to remove some of the air in the fuel out of saturation thus helping to keep saturated air from being removed by very fine micron filters and collecting in the filter head or other high point. Entrained air is however nullified when under pressure from a lift pump.

_________________
Manure green 2005 CRD sport4x4, GDE Hot tune, Cat Gut, OE skids, Draw tight hitch, Duramax lift pump, 160K on multiple varieties of fuel, XM radio, Escort live with Redline, fog light mod, GPS, Icom IC7000 all band radio call sign KC9QPF, Grabber AT2s on Soft 8s, FIA grill blanket.