AUXILLIARY LIFT PUMP CONSIDERATIONS

gmctd · **Posted:** Tue Apr 07, 2015 12:03 pm

To explain historical lift-pump location requirement, at\near engine, at\near tank or (currently) in-tank

NOTE: up thru the '80's, fuel lines were steel lines with flared connections and crimped\clamped rubber tubing, precluding any air leakage in mostly front-pumped vacuum-sourced systems
- 1980's saw proliferation of steel lines with o'ringed connections and steel o'ringed lines crimped into hi-pressure rubber tubing to handle fuel injection pressure reqirements, with relocation to rear-mounted in-line near, at, or in-tank fuel pumps
- late '80's and 1990's saw plastic fuel lines with integral plastic connections utilizing plastic or rubber sealing rings, capable of handling up to 100psi fuel injection pressures
- these were developed in Europe and ASIA, and FORD's blue lines were some of the first to come off the production line here due to their long-association with MAZDA
- DCJ followed due to their long association with MISTUBISHI
- the CUMMINS RAM's kept their SS fuel lines with some rubber and bonded plastic connections thru at least the last '01 production runs in 2002

The KJ CRD has the same plastic fuel lines as the pressurized spark-infested KJ's, but the system is vacuum sourced from the CP3, unlike their in-tank pump-pressurized 60psi systems

So:

Pump types:
a. Diaphragm = high vacuum ability, lower pressure capability
- front-mounted, usually engine-driven off camshaft lobe
- all automotive gasoline engines (EURO\ASIAN exceptions abound)
- no Diesel (GM 6.2L exception)
- electric-motor driven, front or rear service: AC, CARTER, HOLLEY, etc
- NOT flow-thru when failed

b. Piston = positive displacement, high vacuum, high pressure capability
- front-mounted,usually engine-driven off camshaft lobe (mech inj CUMMINS prior to '98 and BOSCH VP44 incept)
- no gasoline
- most Diesel
- no electric-motor driven
- NOT flow-thru when failed

c. Gear - positive displacement, gear-size determines vacuum capability
- large-diameter gears require hi-power drive source
- large-diameter gears supply large vacuum
- large-diameter gears supply hi-pressure
- front-mounted
- usually driven off timing geartrain
- driven off CP3 crankshaft, large gears supply over 180psi pressure, up to 26" vacuum
- electric motor-driven: AC, CARTER, HOLLEY, etc
- compact sizing requires small gears with high-rpm motors to reduce current draw
- very small gears provide high-pressure, very low vacuum capability
- require mounting in or near fuel tank, as spec'ed by oem
- some gear-types not flow-thru when failed due to in-pump bypassing-type regulator*

d. Impeller - slightly positive displacement, impeller size determines slight vacuum capability
- impeller in off-set chamber creates pressure but little vacuum
- best service when totally submerged
- in-tank mounting, or very near tank
- usually with internal bypass-type regulator*
- usually NOT flow-thru when failed

NOTE: version sold by KENNEDY is electric motor-driven with magnetic coupling to impeller to isolate motor from fully-enclosed pumping element = no shaft or other seals to eventually fail

e. Shuttle - solenoid-driven modified hollow piston-type with one-way inlet and outlet valves in the hollow piston shuttle
- piston-type displacement gives good pressure and fair vacuum, based on limitations of plastic one-way valves and solenoid-drive capability
- FACET (40109), AC DELCO (for GM 6.5L TD), usually flow-thru when failed
- electronic drive circuitry has flow-rate sense, such that drive is minimal at idle, increases as flow-rate increses, prevents over-heating solenoid drive electronics and coil during long periods of minimal flow

ALWAYS check unknown\untested versions for flow-thru-when-failed capability to ensure CP3 will get you home

NOTE: no danger of explosions from in-tank mounted electric fuel pumps
- combustion requires oxygen
- there is not enuff oxygen below surface of fuel, gasoline or Diesel, to allow spark-induced combustion
- pumped fuel flows thru motor, reducing commutator sparking
- fuel flow-thru allows positive cooling for more powerful motors
- wiring connections exposed to oxygen above surface of fuel are positive-connection type, non-sparking IF correctly assembled during repair

KJ has pressure-type fuel line connectors, inefficient in vacuum-type oem configuration where front-mounted CP3 lift-pump is "drawing"
thru hi-mounted filter from low-mounted fuel tank
- warm ambients preserve 'live' conformance sealing resiliency
- long periods of cold ambients decrease 'live' conformance sealing resiliency = vacuum leaks

Electric lift pump should be installed
- in-tank (preferred, best)
- in-line near tank (better)
- or, at very least, in-line prior to filter head unit (good)
- NOT between filter and CP3: this location reduces effective "draw" at tank, can "mask" vacuum leaks until towing or loaded, is similar to current oem CP3 system configuration with it's associated problems

REPEAT FUEL DELIVERY PART # QUESTIONS

Revised Fuel Filter Head kit - 68043089AA with filter and wire\plug adaptor
Wiring\Adaptor Plug - 68043086AB
Fuel Filter - 52129238AA (NAPA: FIL 3647, WIX: 33647)

Cummins in-tank lift pump
CARTER P76148M
AIRTEX E7181M
DCJ (P)52121447AD

12v external in-line lift pump
AIRTEX E8251 3-5psi best for post-filter mounting near fuel filter head
FACET 40109 12-15psi best for pre-filter mounting near fuel tank

All items can usually be found on eBay

Pictorial showing replacement to upgraded filter head:
- viewtopic.php?f=5&t=64260

Pictorial showing installation of Cummins in-tank lift pump:
- http://www.auerbach.ca/kj/lift_pump/

Posted R&D of factory in-tank lift pump installation
- viewtopic.php?f=5&t=25447

dan86 · **Posted:** Tue Apr 07, 2015 2:33 pm

Good write up. it'll be helpful to a lot of people I'm sure. I've been looking at a few unbranded ones just recently and struggling to find any that claim to be flow through. When I ask the seller if they know, their response is usually 'yeah, should be'
On a side note, what or sure is suitable for the pump. About 5-10psi?

gmctd · **Posted:** Tue Apr 07, 2015 3:08 pm

The CARTER\CUMMINS in-tank pump is 9-12psi - I've not tested any higher, but I'd think 15psi would not be detrimental

It's the volume you need be concerned with
- a 200gph pump is not necessary
- 4mpg fuel economy at 50mph is 200gph?
- it's more like 12.5gph
- 10mpg would be 5gph
- 35gph is acceptable flow volume for normal use

Good way to determine flow-thru is to put the outlet barb in you mouth, see if you can suck air thru the pump
- don't try this with a pre-owned unit, as you'll likely suck fuel into your pie-hole
- also be aware of used\tested pumps returned and restocked
- they should have strong fuel odor

Viable flow-thru-when-failed pump should take about as much effort as sucking a thick milk-shake thru a milk-shake sized straw

dan86 · **Posted:** Tue Apr 07, 2015 3:21 pm

I know how to test it, but not handy if you can't see it before you buy! The one on ebay I'm looking at is 4-6psi and up to 110ltr/hrs. Sound ok?

gmctd · **Posted:** Tue Apr 07, 2015 3:32 pm

Specs sound good, but deciding factor is flow-thru capability - p'r'aps you could locate similar item locally for visual\hands-on\mouth-on perusal - surely they carry similar in all automotive emporiums over there?

dan86 · **Posted:** Tue Apr 07, 2015 3:43 pm

I'll need to investigate further I think

flash7210 · **Posted:** Tue Apr 07, 2015 3:43 pm

I use a Facet 40109.
about 7 psi.
Has check valve to prevent drain back.
Fails in the open position, flow-through

papaindigo · **Posted:** Tue Apr 07, 2015 3:50 pm

Alternatively post a link to the e-bay pump and maybe someone will recognize it.

Or alternatively the Facet 40109 is a known good flow thru pump and available in the UK from Amazon UK, or thru Motorsport Tools thru their UK ebay site

dan86 · **Posted:** Tue Apr 07, 2015 3:57 pm

Unlikely anybody will recognise it as it is just a universal pump, but here's the link anyway
http://pages.ebay.com/link/?nav=item.vi ... 50&alt=web

flash7210 · **Posted:** Tue Apr 07, 2015 4:09 pm

That sure looks like a Facet.
Don't know the model number though.
But the specs seem right.

papaindigo · **Posted:** Tue Apr 07, 2015 4:41 pm

It's not a Facet. Flow direction is right but both inlet and outlet ports on Facet are much longer.

Googling the P502 part number for a fuel pump brings up a bunch of sources for a PEFP P502. Digging further it appears PEFP = PERFORMANCE Electric Fuel Pumps which lists a P502K as a "Bomba Cuadrada de Baja Presion Universal" pump that looks identical in their catalog but provides no specifications.

I cannot prove it but I strongly suspect cheap Chinese knockoff of a Facet and the only on line review I can find, which is for he PEFP P501 says just that.

Internet is a wonderful thing. As always if it's too cheap to be true it's not true.

dan86 · **Posted:** Tue Apr 07, 2015 5:01 pm

Thanks for the info. I only picked that one because it looked as though it would do the job and was cheap. I'll look into the facet pump.

ebbnflow · **Posted:** Wed Apr 08, 2015 12:29 am

I also use the facet 40109. Mine is mounted in the engine bay.

dan86 · **Posted:** Wed Apr 08, 2015 3:06 am

Oh right. any particular reason why you mounted it there? would have been more efficient closer to the tank surely.

dan86 · **Posted:** Wed Apr 08, 2015 3:40 am

To anybody that has a lift pump fitted- can you post photos please?

papaindigo · **Posted:** Wed Apr 08, 2015 11:18 am

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

If you want BlackLibertyCRD's in engine bay install with pics shoot me an email, not a PM, and I can send you a copy as his online images seem to have disappeared.

ebbnflow · **Posted:** Wed Apr 08, 2015 12:14 pm

Pics of my install are down a little ways in this thread:

viewtopic.php?f=5&t=64097&p=708682&hilit=battery+pump

I chose the engine bay for simplicity. Fuel pump relay is in front of battery. I only needed 2 feet of wire. It was easy to plumb into fuel feed with only a couple feet of hose.

I have not had any fuel related issues since installing this pump in this location.

dan86 · **Posted:** Wed Apr 08, 2015 1:19 pm

ok. so I've just been out and checked the wiring under the rear seat. found a block connector with 8 wires and checked voltage to each one with ignition on and off. The only one with any power when ignition is either on or off is terminal 5. Solid yellow wire. My guess is that's for the fuel gauge?

With the absence of the wire that others said to tap into, would this be a suitable alternative?

gmctd · **Posted:** Wed Apr 08, 2015 1:45 pm

Specifically, do NOT use that wire

You'll need to install the (missing) Fuel Pump relay and Fuel Pump relay Fuse in the power distribution box, as indicated in the article(s)
- and, it's going to supply power for only 5secs at key on
- if START is not keyed and crankshaft does not immediately commence rotating, ECM powers the relay off to prevent disastrous fuel dump

Unfortunately, the EURO wire color scheme seems different than the US version
- pin 2 in that connector from the front should be the factory-installed fuel pump power wire
- US FSM lists it as DkGry\Orange stripe
- pin 2 in the connector from the tank is factory blank, as no lift pump was factory installed

dan86 · **Posted:** Wed Apr 08, 2015 1:57 pm

I'll see about getting a relay then. When I put it in, which wire should it be. Because the one in the articles isn't there!

AUXILLIARY LIFT PUMP CONSIDERATIONS

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