my jeep has factory wiring for a lift pump!

gmctd · **Posted:** Thu Sep 27, 2007 10:38 pm

For your consideration -

Ambient conditions: temperature and humidity - in-tank fuel volume - time interval - how do these compare at each incidence?

Ambient temp can be 90deg, but behind the car in front of you the air can be 140deg in traffic, as can the surface temp of the roadway - differential, trans and engine are all affected - results in greater thermal load on the cooling system - also effects greater tire rolling resistance

Low fuel volume means the tank heats up much quicker from return fuel and increasing roadway temps, results in greater aeration - aeration 'starves' the fuel system and engine response

Time interval should be compared at similar temp and humidity conditions for similar mass air flow thru the intake system, which effects engine response.

Lower temp ambient conditions generally always effect increased engine response

JHCRASH · **Posted:** Thu Sep 27, 2007 10:52 pm

Ok so with all this reading question still unanswered.Lots of good tech though.

Q:Are we all basically saying we would be dumb not to install a lift pump?

Threeweight · **Joined:** Mon May 14, 2007 5:57 pm **Posts:** 679

I dunno if thats what I'm reading. I'm reading some folks swearing by the lift pump, some folks thinking the lift pump might be unecessary with a better filter/filter head and a cooler for fuel returned to the tank, and MrMopar speaking somewhat cryptically about how the whole system works and how it could be improved.

It sounds to me as if a lift pump is the best way to solve the air in fuel issues with the current flawed filter head. However, it does not solve other issues with the filter head (like the heating element burning out, inferior nature of the filters, etc...) The CAT conversion can help with the poor quality of the filters, but all this might be rendered moot if there is a recall to replace the filter head.

Some folks think a better filter head/filter system, like the Racor 230 originally used in the diesel Liberty's in Europe, could solve all of the above problems. Downside is it might be pricey, and might also be rendered moot by a recall. It does not seem to have been tested extensively as a solution yet.

If I am reading Mr. Mopar correctly, the old fuel rail used in the 2.5 liter diesel in the older Euro-spec Liberties needed a lift pump to function correctly. The fuel rail used in our 2.8's does not. The spec's for our new 2.8 matches up with the fuel filter head we have, but that doesn't speak to the quality of the assebly or other flaws with it. From what I've discerned, our fuel rail has tight specs and one would need to be careful with a lift pump not to exceed them (as some folks are being). I haven't seen anything that speaks to the issue of the Racor 230 filter as being a good or bad application to match up with our fuel rail.

flash7210 · **Posted:** Fri Sep 28, 2007 7:35 am

gmctd wrote:

That could be done like retmil46 or blackliberty or one of the members did it, with a bypass or'ed into the normal fuel return line - or just let the Inj Pump handle it - the Delco pump powers down as head presure is reached, and stays down until pressure drops, then will pump only enough to maintain pressure - when flow begins, so does pumping - and it's fully electronic so no points to wear out - they last ~50-60kmi in the GM's, more or less depending on OBD1-OPS controlled or OBD2-PCM controlled (like Jeep) but with redundant OPS control

A flow-thru lift pump is required to prevent CRD Inj Pump damage if the lp fails, particularly at hiway speeds, where rpm is up.

I am confused about the 6.5L pump you mentioned.
The one I was looking at was cylindrical in shape, had an inlet on one end,
an outlet on the other end, and two wires.
I guess I just dont see how THIS PUMP alone is able to regulate itself,
electronically.
Wouldn't some sort of pressure sensor be necessary?

Joe Romas · **Posted:** Fri Sep 28, 2007 8:57 am

Flash

I put on a Facet 40106 pump (NAPA #610-1050) It has a in, out and two wires like what you mention but it's square. As Blacklibertycrd stated, you can blow and suck through both sides so there's no restriction, just be carefull they come filled with some type of oil :cry:

. However it does shut off when 7 psi is reached and on when it gets down to 4 psi. It also seems to vary the pluse speed. I'm guess on the exact on/off pressures but that's what it says and it does come on and off :wink:

gmctd · **Posted:** Fri Sep 28, 2007 10:40 am

Good question - the fuel pump is a solenoid-driven spring-return shuttle with two one-way valves - an electronic solid-state switch drives the two-coil solenoid, and is controlled by voltage from the feedback coil - pressure is regulated by spring tension, current thru the drive coil and feedback coil voltage - when pressure limit is reached, the drive coil can no-longer actuate the shuttle - shuttle stops, feedback voltage drops and the switch reduces drive to the coil - as fuel pressure drops, the shuttle begins moving, feedback voltage increases, and switching action begins again - voila! - pressure regulation at it's best.

I've not had any hands-on with that solid-state Facet pump, but Purolator markets it, so if it is flow-thru type, then that should work as well as the GM pump, and prolly a lot cheaper and lots easier to mount.
Flow-thru test method is lightly blow into the INLET side - shouldn't take more than a baby's breath to get airflow - if you've got to huff and puff and get all red in the face, with the store manager rushing over to see if you're ok, pass it up.

From MrMopar's recent input, I would seriously consider a bypass if installing a lift pump - don't remember the member's handle, but he posted pics of a good example.

My official position on installing a lift pump is, I think the system should be pressurized from the tank forward - brand-loyalty aside, Ford and GM and Dodge install lift pumps in their CRD systems - Jeep conveniently provided us with lift pump circuitry under ECM control, and a frame-mount location back near the tank.

However, MrMopar indicates from DCX official CRD R&D laboratory that the Jeep CRD system will\may be farkled by applying fuel under pressure to the inlet of the C3 Inj Pump - the jury is out on that one without further input - considering that it is correct, a scantool can be used to verify any problem, and caution is indicated until then.

As I indicated, #2 son ain't too keen on allowing dad to hook up a bunch of mysterious DrFrankenstein equipment to his 'new' Jeep, so it will have to wait. (#1 son still faults me with blowing up his new kludged-in Panasonic trunk-boomer (loud noises, sparks, smoke, and all the prerequisite fireworks!), but that's another tale for another campfire.)

Stopgap approach is use a bypass if you install the lift pump - that reduces pressure at the C3 input if you select a low pressure low volume pump - again, 15gal\hour @ 60mph is 4mpg - that rating is more than sufficient for what you're trying to accomplish - 'mine is bigger than yours' don't work, here, guys.

Warranty considerations dictate that you kludge-up the installation for easy switcho-changeo at each official visit to MrService (how you gonna manage that, broke down on the side of the road in Timbuctu, only tool in the glovebox being the significant other's blow-dryer?) - convenient temporary location for that is adjacent the fuel manager\filter, as shown in the pics.

chrispitude · **Posted:** Fri Sep 28, 2007 10:47 am

Great summary, gmctd. It sounds like fuel cooling may need to be part of the lift pump/bypass package, but perhaps the jury's still out on that too.

I hope that the NHTSA forces a solution to come from the factory, and it comes in the form of a factory-engineered lift pump. Then again, given the "factory engineering" I've seen so far...

- Chris

flash7210 · **Posted:** Fri Sep 28, 2007 12:50 pm

Thanks GMCTD.

So the GM pump is solenoid driven.
I always thought solenoid pumps were noisy, but yet the '00 van at work
with the 6.5 you don't hear it at all. I guess newer ones are quieter.

When you mention a bypass, how do you control how much fuel gets
bypassed to the return line and how much goes to the engine?
Or, is the system self regulating?

Kniggit · **Posted:** Fri Sep 28, 2007 3:51 pm

basically, if you don't buy a 4GPM pump and over pressurize the lines then there should be near 0 pressure at the connection to the return pipe, and if it is flowing properly you should have WAY less than 1psi on it, so its basically good ol' suction from that tee forward.

K

CATCRD · **Posted:** Fri Sep 28, 2007 4:25 pm

flash7210 wrote:

When you mention a bypass, how do you control how much fuel gets
bypassed to the return line and how much goes to the engine?
Or, is the system self regulating?

You would need an orifice in the return line of about .020" to restrict the bypass, sending most flow to the CP3.

BlackLibertyCRD · **Posted:** Fri Sep 28, 2007 4:45 pm

The facet pump is electronical controlled.

http://www.facet-purolator.com/solidstate.asp

I used 40109 and and the automatic bleeder setup and I don't have any problem at all. I just filled the tank yesterday after running very low and the fuel in the filter was clear as a bell, not foaming like some one believes. I telling the truth when I say that this is the mod I wished I did long ago because the CRD starts and run like a dream. It never ran this good even brand new.

gmctd · **Posted:** Fri Sep 28, 2007 5:18 pm

Sorry fer the delay - the kid just dropped by, almost with tears in his eyes - the Jeep was squealing and rattling and protesting something mightily - what could it be? - what's wrong? - popped the serp belt, checked all the pulleys and tensioner, all good'n'tite, no noises - turns out belt had crunched sand and some melted plastic stuff in the grooves - found the remains of the plastic in the nook behind the lifting eye - found the remains of the previous Provent installation down under the crank pulley, with many custom-designed grooves in the tubing walls - wonder how those got there - took my linoleum knife and a wire brush, cleaned the ribs and grooves and belt surfaces, gave it a scrub in bleach\detergent mix I had been using to demildew the house trim B4 scraping and painting it - voila!......no more squeaks.......well.......maybe.......just a little - but he left happy - and, of course, B4 I could reach for the Lab equipment stuff - oh, well....................

Folks, I gotta tell ya - assuming that that's the original belt at 53kmi, that oem quality jist cain't be beat - the ribs were totally un-cracked, unsplit, un-unraveled - the belt compound was just as 'live' as a new one - it was a real pleasure cleaning it up and re-installing it - tole the kid to see MrMoparts at his earliest convenience, pick up a new specimen for the next 50kmi.

So, where were we - ok, the 'summation' was in reference to the lift pump question - proceed with caution.

My official position on the return-fuel cooler is: throw caution to the wind - doit - git'er done! Should be no warranty concerns at all if you do it professionally.

'Nuther words, don't show up fer the service checkup with frayed hoses on a ratty cooler hanging down below frame level, suspended from a bent clothes-hanger which is wrapped around the harness for the rear lights - not even good fer yer image, dudes!

Concerning the bypass, the C3 IP will consume as much fuel as it requires - all the rest will bypass to the tank, at a rate dependent on diameter and pass-thru spec of the check-valve, and the feed at the Tee - which is why you should use a pump with minimal pressure and volume - to be any more specific will require a pressure guage calibrated in "H2O in the oem return line, and another for 5psi in the planned lines - and we'll need the C3 specs to further determine system requirements - I think the system posted by one of the members here is worth looking into, tho.

A note, here - if the ECM is basing C3 inlet requirements on Barometric pressure, say, for altitude compensation, then yes, adding a 5psi lift pump could be detrimental - poser: how far below sea level would 19.696psia be?
Remember - we're talking O, not H2O - and how will ECM handle that - a trickle, or a torrent?

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

BlackLibertyCRD wrote:

The facet pump is electronical controlled.

http://www.facet-purolator.com/solidstate.asp

I used 40109 and and the automatic bleeder setup and I don't have any problem at all. I just filled the tank yesterday after running very low and the fuel in the filter was clear as a bell, not foaming like some one believes. I telling the truth when I say that this is the mod I wished I did long ago because the CRD starts and run like a dream. It never ran this good even brand new.

Ok, looking at these pumps, which one is best? One installed a 40109 which is 2.5-9 psi, someone else did the 40106, which is 4.5-7. Also listed is a 40104 and 40105, which have 2-4 psi and 3-4.5 psi capacity, respectively. Which is the best option? To me it seems like you want the lowest pressure as long as it moves enough volume and does not restrict, correct?

gmctd · **Posted:** Fri Sep 28, 2007 5:58 pm

Yes - all that is needed is enough pressure to prevent foaming, and more volume than C3 demand

And, here's the thread with the lift pump and bypass scheme, as example - it's now several threads down on this first page -

http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=24527

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

4104 Moves 25 Gallons per hour
4105 Moves 30 GPH
4108 Moves 32 GPH

So is the 4104 enough at 25 GPH?

gmctd · **Posted:** Fri Sep 28, 2007 8:29 pm

I 'spect the 109 was chosen because it matched the 3/8" fittings on the fuel manager, not by the pressure\volume rating, alto there was some talk here of using the DMax pump - most of the other Facets are 1/8"npt - pipe is measured inside diameter, tubing is measured outside diameter - dunno if that's a typo, but I'm having some difficulty imagining a fuel pump with 1/8" dia fuel lines - maybe on a lawnmower - for ref, in the thread pics, the white nylon tubing is 1/4"od, which means it's less than 3/16" id, which is fine for the bypass - I would suggest installing a pump with system-diameter fittings, so the 109 seems the best choice outta that bunch - you can deal with the increased pressure by using the bypass

Remember - this is predicated on that being a flow-thru pump, where you can easily blow thru the valves

BTW and FYI - saw a special on the forum here on those Facet lp's for ~27bucks - check it out

CTI - I prolly oughtta get a couple fer some R&D

gmctd · **Posted:** Fri Sep 28, 2007 10:11 pm

Dunno why this keeps slippin' my mind, but - the small one-way check-valve in the bypass feed is necessary to prevent hot return-fuel from feeding into the C3 if the aux pump dies - don't leave home without it

Stan Wright · **Posted:** Sat Sep 29, 2007 12:52 am

Installed the Racor 245 and Kennedy fuel pump today. The Racor installation was easy. The fuel pump was a little more involved. It might be my imagination but the Jeep seems to have a little more throttle response right off idle. It is definitely quieter...much less rattle. I hope to get installation pictures up tomorrow.

Edit: Here are the installation pictures:

http://liberty.eurekaboy.com/racor.htm
http://liberty.eurekaboy.com/kennedy.htm

gmctd · **Posted:** Sat Sep 29, 2007 2:31 am

Good - what are the specs on that pump?

Ok - I have two of the Facet 40105 1-4psi 30gph pumps in my sweaty ole hands, even as we type - talk about yer quick shipping!

At this time I would not recommend any of the 1/8"NPT pumps for this install, due to the 40105 dimensions -

1/4" hose barb to 1/8"NPT fittings, ~0.217 i.d
NOTE: 3/8" barb to 1/8"NPT would allow ~0.280" i.d.
3/8" tubing is 0.375" i.d.

pump inlet i.d. is ~0.320 thru the npt threads

pump outlet i.d. is ~0.260 thru the check-valve cage, ~0.320 thru the threads

It is an easy blow-thru pump

Be interesting to get the 40109 dimensions - or pics - hint, hint...............

retmil46 · **Posted:** Sat Sep 29, 2007 10:39 am

gmctd wrote:

Good - what are the specs on that pump?

The Kennedy lift pump is the one you've already dismissed for costing $200.

my jeep has factory wiring for a lift pump!

Who is online