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Discussion Starter #1
Has anyone ever had problems with a lift pump getting weak?


I think mine is going bad, long uphill pull with moderate throttle truck acts like its running out of fuel. It slows down and there is no responce from the pedal, no codes either, if you take your foot off the throttle for about 5-15 seconds and lay into it again it's got power for a little while longer. The longer your foot is off the pedal the longer you get power when you lay back into it. More throttle = quicker running out of power. It only does it with a chip on it.


I bought the stuff second hand in the picture below, anybody know how/where to put the pump. I thought it would be a simple replacment part. Do I need to remove the stock one, it's in the tank right?


Any help or comments would be great!


 

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That's a Kennedy Diesel mega secondary filter set-up .... Hopefully he will chime in or someone with the setup will assist ...





Your problem is confusing ??? Do you have a lift pump in place now ??If not and your having a fuel starvation problem as you describe ,unless your running some new fuel enhancement box on the market,I would change the OE fuel filter ..... That should or might cure your ills ...








Mac
Edited by: Mackin
 

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DF: your loss of power situation sounds like a dirty fuel filter or some air inleakage in the fuel supply. You have made a regular changeout on your OEM fuel filter at least every 10,000 to 15,000 miles, right? You may want to check your OEM filter for proper seating, but if it were allowing air inleakage, there would probably be a loss of prime associated with that. There is no lift pump on a Duramax and no pump in the tank. The Duramax injection pump pulls suction on the fuel line from the tank all the way to the pump in the front engine valley. Your kit pictured is a Kennedy Mega Filter head and Baldwin cartridge along with a lift pump and some of the components you'll need to hook it up. Filter head mounts under the airbox in the front of the engine compartment on the passenger side. It can be plumbed into the fuel system as a pre- or post-OEM. You'll find installation instructions with pictures on the Kennedy Diesel webpage www.kennedydiesel.com


The lift pump is a more complicated install inside the driver's side frame rail forward of your fuel tank. You'll have to cut the stainless fuel supply line there and splice in the pump as well as coming up with a method to mount the pump to the rail. The pump will require switched 12v power as well as the oil pressure switch that will kill power to the pump when the engine is not running. Pressure supplied to the system is regulated by the bypass needle valve on the lift pump. I have a Mega Filter on my truck, post-OEM but do not have a lift pump, so this is about all the information that I can provide you on that.
 

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Which truck are we dealing with, the 2001? Could be setting some default codes. Here's some air box tips:


http://www.kennedydiesel.com/dmaxairintake.html





This mentions a bulletin pertaining to this as well as software updates.





If the 2003 has a K&N FIPK, that could be the casue.





From there we can deal with the installation of the lift pump/filter. I do not believe that this is a starvation issue UNLESS the OE fuel filter is plugged...


Edited by: Kennedy
 

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Diesels Forever mentions this only happens when it's on the CHIP. Could this be a simple case of defueling due to increased power, or am I reading this wrong?


JP
 

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Discussion Starter #6
I change my filter at every other oil change, yup it's the 2001, and at first I thought it was a clogged filter so I put on a new one ahead of schedule. It still does it. I've been setting some codes, mostly tranny: safe mode, exess tc slip, and incorrect 5th gear ratio. I also set a overboost code at same time as tranny codes, figured it was related to tranny taking a dump. Can the tranny shut down the truck like its doing? I know tranny is getting weak, I've got 55,000mi. all with some sort of chip, I need a ATS or TransGo, bad.


"There is no lift pump on a Duramax and no pump in the tank. The Duramax injection pump pulls suction on the fuel line from the tank all the way to the pump in the front engine valley."


Sounds like a bad design to me, but what do I know



Oh yea, I've already liberated my airbox with a 4" hole saw.


Anyway, all comments are appreciated.


Edited by: Diesels Forever
 

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What setting have you been running on your TST? I hear that it makes more than enough power to waste a stock Allison. Could be that the tranny is causing the engine to go into limp mode as it detects slip. Someone with more knowledge step in here - end of a long week and things getting a bit fuzzy.
 

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I think you solved your own problem just looking for confirmation .... A lift pump isn't going to solve a thing for you ....

Are you going to third hand the Mega lift pump kit ?? There's a classified forum 23 clicks below .....


Mac
 

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Sounds like you did your own air box mods, and while well meaning, you skipped the key part. The one that only dealers and those with Tech 2 Flash capabilities can do. ECM programming! There were updates for false overboost codes early on with the 2001 trucks.





While a lift pump is not necessary, I'd still suggest installing it, and the filter. Looks like you have all of the goodies ready to go!





Sounds like the TST is killing your Allison...
 

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I was still getting the overboost even after the updates... defueling with lp set them.

Juice cured it woooo hooo!
 

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hoot said:
I was still getting the overboost even after the updates... defueling with lp set them.

Juice cured it woooo hooo!




The Juice "caps" the boost signal. Most other modules do the same.
 

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Discussion Starter #13
I run the TST on 6hp and 4te usually. 9 & 9 when some little chinese racer car pulls up thinking he's going to take me. I only have the problem at highway speeds, must be the tranny. I've had a VanAiken (sp?), a hot Juice, the TST, and a reg Juice, I get the most "seat of the pants" power from the TST. Maybe it's giving me that power by sacrificing my tranny? Does anyone else have a TST?


Kennedy, Do you think a suncoast will let me run on 9&9 without codes? Supposedly I was flashed with latest updates last week at the dealer, when they checked out my codes and zip-tied up my electrical connections on the engine so I wouldn't put a chip on it.
 

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I think the Suncoast would be fine. Level 4 is likely enough. Sdaver has had excellent luck, ANDhas pushed it much harder than most.





If you suspect fuel starvation, here's a sneak peek of the prototype gauge that I use to test restriction:

















This unit can also be used to set up low psi lift systems...
 

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Kennedy wrote:
"I think the Suncoast would be fine. Level 4 is likely enough. Sdaver has had excellent luck, ANDhas pushed it much harder than most."



That's open for debate .... What's really in Super Bears tranny ?? I grenade a Suncoast with less power with MORE then what Daver has in his tranny,I'll bet .....Seen her with my own eyes ......

Mac
 

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Diesels Forever,


I also run a TST. Now it's a comp box. My TST will cause an overboost that dosen't always set a code, and almost always at highway speeds, usually with cruise on and pulling a hill. On mine it drops to 2000 rpm, won't go over that, if you push down on the accelerator pedal she'll downshift, but won't go over 2,000 rpm so you lose more speed. It clears in about 10 sec or so. It goes something like this. Your cruising down the highway at about 80 ish or so and while pulling a hill the truck falls on it's face, slows to 2000 rpm and will maintain that, in 10 sec or so truck comes alive and because the cruise is on, downshift is inhibited and you limp the tranny
 

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Mackin said:
Kennedy wrote:
"I think the Suncoast would be fine. Level 4 is likely enough. Sdaver has had excellent luck, ANDhas pushed it much harder than most."



That's open for debate .... What's really in Super Bears tranny ?? I grenade a Suncoast with less power with MORE then what Daver has in his tranny,I'll bet .....Seen her with my own eyes ......

Mac

Dunno, but from what I hear, he is considering the L5 upgrade. IMHO, the only failures with the Suncoast (no offense, but I'm going to be offensive here so don't take it personally) is from guys NOT using their heads and doing frequent, and excessive burnouts with every ounce of power they have on tap
. For a guy who drives/tows normally, the L4 is just fine...





FWIW, I'm NOT planning to install the L4 Suncoast that I have on hand as I want the security of the L5 upgrades knowing that I sometimes lose my head as well...



Edited by: Kennedy
 

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a64pilot said:
Diesels Forever,


I also run a TST. Now it's a comp box. My TST will cause an overboost that dosen't always set a code, and almost always at highway speeds, usually with cruise on and pulling a hill. On mine it drops to 2000 rpm, won't go over that, if you push down on the accelerator pedal she'll downshift, but won't go over 2,000 rpm so you lose more speed. It clears in about 10 sec or so. It goes something like this. Your cruising down the highway at about 80 ish or so and while pulling a hill the truck falls on it's face, slows to 2000 rpm and will maintain that, in 10 sec or so truck comes alive and because the cruise is on, downshift is inhibited and you limp the tranny




The Quad 215 sometimes will do this as well. It did it to me at a truck pull. I've been running a Juice to cap the boost signal, but figure a simple inline boost module might be in order...
 

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Discussion Starter #19
a64pilot, You are describing my excact problem. I thought it was fuel related. Shows how much I know.
What year truck are you running? Does anyone know how to mask the boost signal? Maybe that will cure me for a while until I can get a tranny.
 

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No offense John ....


I was just blowing off a little steam ,as the $$$$ is starting to add up in this LIL adventure ...


Not to mention my Tranny Mount got misplaced,in the practical month it sat under a bench with my T-case,which has delayed me anouther day ...Long story ....


I'm just bumming ....





Mac
 
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