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Discussion Starter · #1 ·
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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John Kennedy has run his pump for more than 10 years with no issues. I’ll 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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Discussion Starter · #3 ·
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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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.
 

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Discussion Starter · #6 ·
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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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.
 

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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.
Ya, doing that return fuel line thing can be pretty complicated and very time consuming installing it.'uhNo

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

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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 :rofl
 

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Discussion Starter · #11 ·
I’ve been looking for a shop I can trust to build the transmission I know it’s a weak link. For the most part I baby this truck but I have to let it eat a ford F-whatever every now and then lol.
 

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I’ve been looking for a shop I can trust to build the transmission I know it’s a weak link. For the most part I baby this truck but I have to let it eat a ford F-whatever every now and then lol.
Mike L, Inglewood, CA, the best in the Allison rebuild business

You can find cheaper you CANNOT find better. and in this case you DO get what you pay for!
 
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The other great thing about Kennedy pumps is if they stop running the injection pump can pull fuel thru them
 
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I have a brand new uninstalled set of Kennedy twins for LML or? My LML blew up before I installed them , have not listed them yet but will shortly .
Kennedy Diesel
 

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The other great thing about Kennedy pumps is if they stop running the injection pump can pull fuel thru them
Ditto with the AirDog, this I know as fact. :thumb
I installed a switch so I could shut mine off with a LED light showing its either off or on, under the dash, I 've driven for several days and towed with my LP shut off.
I did this so when I have mine in a shop the LP won't be constantly running when they have the key on, much easier than popping the hood to remove the fuse..
 

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The FASS pump is also a flow thru design.

Im NOT saying the Kennedy is not a good pump, I am saying that the lack of a flow thru is not a reason not to choose FASS or AD.

IMHO All 3 are good pumps.
 

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That settles it then, all 3 are flow thru and all 3 are good.
There’s no reasoning anymore to bash any of these 3 liftpumps, other than maybe customers choosing larger than needed LP’s because they think “bigger is always better” 'uhNo and they might need a sump because of their choosing.
 

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Thanks to DRC and 407driver, I didn't know about those pumps were flow thru. Always ready to learn something new.
 

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And yet, there are thread posts where it was not flow thru and the truck was dead.
cough..cough...FASS....cough..cough marx
:rofl
 

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And yet, there are thread posts where it was not flow thru and the truck was dead.
cough..cough...FASS....cough..cough marx
:rofl
I had unplugged mine for about a week while I was troubleshooting some electrical issue (don't recall exactly what or why).

Some highway driving some in town maybe a total of 300 miles in that week (back and forth to work mostly) but it never gave me any issues.

I cant speak for the others that reported issues I can only relate what happened, or in this case, didn't happen to me.

I do wonder if, based on the design of the actual pump itself if it would flow fuel if the motor seized. Presumably the impeller would not be able to turn thus impeding any flow through. I guess that would be a question for the FASS engineers, wouldnt it?

I can tell you that when I lost my first 08 to a business bankruptcy and replaced it with another 08 the people at FASS let me transfer the warranty over to my new truck. I thought that was a good Customer Service decision
 
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