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Old Post State In Tank Lift Pump Harmful?
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=74445
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Author:  thomas04 [ Sun Mar 10, 2013 12:54 pm ]
Post subject:  Old Post State In Tank Lift Pump Harmful?

Gooday.

Reading an old post from Dec. 31 2006, there was disscussions of in tank lift pumps that if installed would cause back pressure issues, black smoke (unburned fuel), poor milage, etc. this was brought up by MrMopar64 from dyno test he had done with a lift pump installed.

Has this post been proven wrong by members of this or installing an in tank lift pump potentially harming the fuel system oin our Jeeps?

Peace,

Thomas04

Author:  papaindigo [ Sun Mar 10, 2013 1:10 pm ]
Post subject:  Re: Old Post State In Tank Lift Pump Harmful?

Can you provide a link to that post? As far as I know the only, somewhat recently discussed, issue with respect to in tank or in line auxillary fuel pumps has related to the psi they operate at and a general consensus that ca. 6psi is ok and lots higher psi is to be avoided. Whether that relates to the symptoms you mention or not I don't know.

Author:  CATCRD [ Sun Mar 10, 2013 1:23 pm ]
Post subject:  Re: Old Post State In Tank Lift Pump Harmful?

I remember that discussion from back in the day. Then someone tried it anyway, with only positive results. Then a ton of people did it - nothing bad to report. More than 10psi is unnecessary so go for it if you want.

Author:  thomas04 [ Sun Mar 10, 2013 2:15 pm ]
Post subject:  Re: Old Post State In Tank Lift Pump Harmful?

viewtopic.php?f=5&t=16062&hilit=Fuel+line+diameter&start=0

I agree that the intank pump must work as seasoned owners of this forum promot it up to this day.

Peace,

Thomas

Author:  msilbernagel [ Sun Mar 10, 2013 4:20 pm ]
Post subject:  Re: Old Post State In Tank Lift Pump Harmful?

On the Dodge Cummins 5.9L diesels, it's common to use lift pumps with 15-18 psi and in the years I paid attention no one ever seemed to suffer harm. The Dodges use a CP3 also, though the intermediate pressure is slightly higher, the CP3s on both Dodge and Jeeps are nearly identical.

After having EGR problems @ 30k miles (Jeep), and some air-in-fuel issues, I installed the in-tank pump from the Dodge pickup (the ones used for the Cummins engine). Almost identical assembly except that where the Jeep has an intake tube the Dodge has an inline pump. The tabs are clocked a little differently (trimmed a tad), and this also creates a need to put the Jeep float and wire onto the Dodge assembly (snaps in/out in seconds). With that done, and the wiring harness changes to bring power to the pump, it works great.

Between the SEGR (most use the GDE tune nowadays) and the in-tank pump - it's been rock solid from 30k to 150k miles.

Those are the two nearly mandatory mods required for this rig - the others are secondary: my opinion... ; ' )

Of course, I don't tow - and for those who do the torque converter upgrade is another must-do.

; ' )

Mark

Author:  papaindigo [ Sun Mar 10, 2013 4:32 pm ]
Post subject:  Re: Old Post State In Tank Lift Pump Harmful?

There are certainly a number of folks running with relatively low pressure auxillary fuel pumps, apparently with no problems, either in tank or in line. Of course another option is to replace the prone to leak air quick disconnect fittings with good fuel line.

I've outlined options at viewtopic.php?f=5&t=74417&p=780188#p780188 with some links and my thoughts on what I'd do if I was to add a pump.

Author:  Drewd [ Sun Mar 10, 2013 6:09 pm ]
Post subject:  Re: Old Post State In Tank Lift Pump Harmful?

The MPROP allows only enough fuel anticipated by the CP3 and and remainder majority is bypassed. I think 10 psi or lower should be fine. I've been running a kennedy lift pump for 5 years with no problems.

Author:  warp2diesel [ Sun Mar 10, 2013 7:02 pm ]
Post subject:  Re: Old Post State In Tank Lift Pump Harmful?

That claim has been proven to be pure Genetically Modified Feed Stuff Feed, Male Bovine Excrement (BS).
On other Common Rail Diesel forums, Dudes and Dudettes have had as much as 20PSI (1.36 Bar) of pressure on the CP3 inlet with only positive results. Having the positive pressure from an in tank pump eliminates fuel aeration and lets the engine run much better. In the Bosch book on Diesel Fuel System Management, they recommend the use of lift pumps and fuel coolers, but their Sales People will do what ever it takes to make the sale, even kiss up to Bean Counter Engineers who never played in the sand box when they were young. Detroit is full of Engineers who never saw a sandbox or beach of sand in their life.
One member has an in tank pump with a Kennedy pump acting as a booster pump, his CRD runs great.

Author:  cevans [ Wed Mar 13, 2013 10:52 am ]
Post subject:  Re: Old Post State In Tank Lift Pump Harmful?

Agreed - lift pump installed in 2006, not one problem...other than better starting, easier fuel filter priming etc.

Author:  thomas04 [ Wed Mar 13, 2013 12:06 pm ]
Post subject:  Re: Old Post State In Tank Lift Pump Harmful?

Thanks for all the replys. It is good to get an updated outlook on this subject.

Peace,

Thomas04

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