Lift pump question - Chevy and GMC Duramax Diesel Forum
11-16 LML Performance Parts Discussion Discussion of Performance Parts For the 2011 to 2016 LML Duramax Trucks No Advertising

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post #1 of 24 (permalink) Old 09-27-2019, 06:15 PM Thread Starter
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Lift pump question

I have a chance to get a pair of Kennedy diesel lift pumps for cheap. Question is do I need them and are they any good?
LML
PPEI 5 stage tune
Fuel filter relocation
Egr delete
DEF delete
Full exhaust
4” lift
Hid lights
AFE Cold air intake
Air bags
Jumper seat and stock center console
Upgraded sound system
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post #2 of 24 (permalink) Old 09-27-2019, 07:13 PM
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John Kennedy has run his pump for more than 10 years with no issues. Iíll say this-find one, just one thread on how somebody had a problem with their Kennedy pump. Then search for the threads on other companies out there and read the issues they have. The ratio will be 0/100.
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🤘 Kennedy fuel system support hardware, CCM front Diff Drop, some LEDs to make night into day, got some big ol 20's and wide ass tires and a nice display to show me what's up under the hood-

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post #3 of 24 (permalink) Old 09-27-2019, 08:39 PM Thread Starter
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After some research I’m going with the twin Kennedy setup. Here’s my logic the Fass systems pump way more fuel then I’ll ever use so then the extra fuel gets pumped back into the tank thus creating heat and aeration all of which the Kennedy systems don’t do. Also I’ve read you have to have a sump to remove the air that the pump creates. So at a low fuel situation you could wind up sucking air into you lines. Tell me if I’m missing something.
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post #4 of 24 (permalink) Old 09-27-2019, 08:42 PM Thread Starter
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Sierraluva I’m with you on this for sure! Thanks
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post #5 of 24 (permalink) Old 09-28-2019, 02:07 PM
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So much for trying to be out of sight/out of mind with deletes.

Kennedy is a good way to go, even more so if your getting good prices.
The problems you mentioned with FASS happens when you go with bigger than the FASS 95 or AirDog 4G100 lift pumps.
You only need bigger liftpumps if your engine is producing more than 600 hp.
They claim 500 hp so they can sell you more stuff.
The 150/165 puts out to high fuel psi usually in the 12-13 + psi to the engine which is to high and causes the issues you mentioned in the return line including excess air.
Safe psi for the Duramax is between 8-10.

The sump pulls from a different location away from the stock pick-up and return.
What the companies don’t/won’t tell you is having a sump does nothing to lower the psi to the engine, but you’ll still have a “Niagara Falls” fuel return.

I went from a AirDog FP-100 to a 4G-165 motor had these issues, then swapped back out the 165 motor for a 4G-100 motor, no more issues, no excessive air.
The idea behind the return is fuel is always available for what’s needed at the engine, what’s not used returns back to the tank, which I do like.
I don’t feel the reasons they claim for the air and polishing is really actual facts.
Fuel is not heated up with this process, but it is filtered a little more returning and returning thru the LP, which IMO is a good thing along with having fuel always ready and available when needed at the engine.

Dan
2007.5 GMC Sierra 3500 SRW L.B."BLACK" C.C. 4X4 LMM Z71
DIY stock airbox mod, aFe ProGuard 7, OEM drop-in
EFILive ECM ATP - Heavy Tow Tune with Turbo Brake.
EFILive TCM Duramax Tuner
DHD Cold Side High Flow Intake Pipe
DHD PCV Re-Route
AirDog 4G100

2007 Yukon Denail "BLACK" 6.2 gasser
DIY stock AirBox Mod, K&N, Airaid intake, EFILive TCM only tuning

Last edited by D_R_C; 09-28-2019 at 02:12 PM.
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post #6 of 24 (permalink) Old 09-29-2019, 12:27 AM Thread Starter
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I got the dual Kennedy set up installed today. I had to get under the truck to check if it was running it was so quiet. Nice clean easy install. I did a lot of research and found as long as you don’t get to big of a pump setup there all good I just liked not having to do the whole return fuel line thing and how compact the unit is a plus for me. Thanks for all your input.
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post #7 of 24 (permalink) Old 09-29-2019, 04:43 AM
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Quote:
Originally Posted by Jessapio View Post
I have a chance to get a pair of Kennedy diesel lift pumps for cheap. Question is do I need them and are they any good?
LML
PPEI 5 stage tune
Fuel filter relocation
Egr delete
DEF delete
Full exhaust
4” lift
Hid lights
AFE Cold air intake
Air bags
Jumper seat and stock center console
Upgraded sound system
I didn't see a transmission build on that list. Unless you REALLY keep your foot out of it with that Stage 5 that transmission rebuild isn't far off in your future.

2008 Silverado 2500HD CCSB LTZ Diesel
FASS 95 Lift Pump (with Baldwin filters), Edge Insight CTS Monitor on a Windshield Mount, Nicktane Fuel Filter Adapter w/ CAT 306-9199 UHE tertiary fuel filter, Bilstein 5100 Stock Height, Bushwacker Bed Rail Caps, AMP Research Bedstep, Fumoto oil drain valve, Dorman PS Oil cooler, Pioneer AVIC 7200NEX GPS/Stereo, Air Lift LoadLifter 5000 Air Bags.
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post #8 of 24 (permalink) Old 09-29-2019, 05:50 AM
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Originally Posted by 407driver View Post
Unless you REALLY keep your foot out of it with that PPEI Stage 5 ,that transmission rebuild isn't far off in your future.
Order a set of pistons, while your at it...

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post #9 of 24 (permalink) Old 09-29-2019, 08:22 AM
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Quote:
Originally Posted by Jessapio View Post
I got the dual Kennedy set up installed today. I had to get under the truck to check if it was running it was so quiet. Nice clean easy install. I did a lot of research and found as long as you donít get to big of a pump setup there all good I just liked not having to do the whole return fuel line thing and how compact the unit is a plus for me. Thanks for all your input.
Ya, doing that return fuel line thing can be pretty complicated and very time consuming installing it.

Good that you gots your LP installed.
Rig up a led light and a psi gauge off your LP, that way youíll always know your lift-pump is running from your captains chair.

Dan
2007.5 GMC Sierra 3500 SRW L.B."BLACK" C.C. 4X4 LMM Z71
DIY stock airbox mod, aFe ProGuard 7, OEM drop-in
EFILive ECM ATP - Heavy Tow Tune with Turbo Brake.
EFILive TCM Duramax Tuner
DHD Cold Side High Flow Intake Pipe
DHD PCV Re-Route
AirDog 4G100

2007 Yukon Denail "BLACK" 6.2 gasser
DIY stock AirBox Mod, K&N, Airaid intake, EFILive TCM only tuning
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post #10 of 24 (permalink) Old 09-29-2019, 08:27 AM
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Quote:
Originally Posted by 407driver View Post
I didn't see a transmission build on that list. Unless you REALLY keep your foot out of it with that Stage 5 that transmission rebuild isn't far off in your future.
You know darn well they offer trans safe tunes

Dan
2007.5 GMC Sierra 3500 SRW L.B."BLACK" C.C. 4X4 LMM Z71
DIY stock airbox mod, aFe ProGuard 7, OEM drop-in
EFILive ECM ATP - Heavy Tow Tune with Turbo Brake.
EFILive TCM Duramax Tuner
DHD Cold Side High Flow Intake Pipe
DHD PCV Re-Route
AirDog 4G100

2007 Yukon Denail "BLACK" 6.2 gasser
DIY stock AirBox Mod, K&N, Airaid intake, EFILive TCM only tuning
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