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Aux. fuel pump -- nessesary or not?

10611 Views 14 Replies 5 Participants Last post by  Reaper
My LLY goes into limp mode more often than I would like, and I have been told that an aux. transfer pump would solve this. Is that true, and if so, which one is the best way to go?? Thanks.
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Are you sure it is limping the engine or tranny? What codes are you getting? When is the last time you changed your fuel filter? Do you have any mods? We will need more info to help you out with a decision.
Thanks for the reply. I beleive it's in limp mode, however I don't know how to check for the codes. Can you tell me how that's done? Fuel filter has not been changed yet. I'm running the Edge-Juice. I'm planning on buying the Attitude module in the near future. I use the truck for a daily driver and also for pulling a gooseneck. I sell used construction equipment-Dozers, backhoes, etc. and so I usually load fairly heavy.
do you get "shift range inhibited" on the DIC and a reduction in power? Do you have a check engine light when it does this? When was the last time you changed your fuel filter? If it has been a long time (over 5000 miles) change your fuel filter first. As far as checking the codes, you can go to the local Autozone and they should be able to pull the codes for you. Also, I believe there is a TSB out for the #2 and #7 injector harness chafing. Also, what power level are you using on the Juice? There is also a tranny spin on filter that needs to be changed at intervals probably no more than 10,000 miles. This is about all the help you can get without codes.
Do you have mods?

lift pump instead of aux transfer pump i think is what youve heard. If you have limped the truck that wont help. Limping is a personal problem.........oops wrong limp...........limping is when the transmission slips enough to , well limp it, you wont be able to go over 2k rpms in limp mode. If you turn off your truck it usally resets limp mode.

A lift pump helps if your running tuners that suck the fuel system dry.
I was told that the fuel system get depleeted when you accelorate too severly, and that is what causes limp mode. So is that true? Or is limp mode just caused by the trans. slipping? It's a real hassel to pass another vehicle only to then have to pull over and turn off the truck for resetting.
yeap if you have to pull over and reset your limping. Thats a tranny problem and not a fuel problem. The fuel system can get depleeted but thats not limping.
So, what programmer you have on your truck??? I would suggest to back down the power before you have to do work on your tranny. I would try and change over to synthetic fluid and change your spin-on tranny filter and see if that helps at all.
I just changed the spin on filter, and the trans fluid. I've got the Edge Juice and have only run it on level 2. That doesn't seem like it should be too much power when you're just passing with out a trailer on back. Should I consider one of those extra deep sump pans for the trans?
Does any one sudgest a particular synthetic trans. fluid?
THe engine can go into limp mode for low rail psi(p1093) also, this will limit you to 2000 rpms also and can be caused by a dirty fuel filter, high hp programs(level 5 on a juice), or a combo of the both, add a trailer and it will magnify the prob even more!

I'm not saying it isnt a trans issue, but it could ba a fuel supply issue also!!
THe engine can go into limp mode for low rail psi(p1093) also,
I have never in all my time of owning my truck heard that. If im wrong disreguard my last posts.:D
Mine used to limp for 1093 all the time untill i put the shim kit and lift pump on and even did it once after that. The pic thats in my garage of the truck pull, after that pic i only went about 10 more feet untill the truck shut down (1093)to a 2000rpm limit and im pretty sure my trans wasent limping:) !
I just changed the spin on filter, and the trans fluid. I've got the Edge Juice and have only run it on level 2. That doesn't seem like it should be too much power when you're just passing with out a trailer on back. Should I consider one of those extra deep sump pans for the trans?

Are you the first owner of your truck?? Reason for asking is the person before you could have used a handheld programmer and beat the tar out of it....that is why you could be having your problems...if they are tranny related. Have you tried to take it anywhere for codes to be checked? As far as tranny fluid...any quality synthetic is good.....Mobil 1 (it's what I use), transynd, and amsoil...there are more, but those are the 3 most people use.
Sounds like a P-1093.
If you haven't changed your fuel filter yet I would start there.
I have had P-1093's pop when I am at a 1/4 tank or less when getting into the throttle and letting off quickly in level 3 and I had the injector harness ground out and cause the P-1093 so you might want to check that as well.
If you don't have any of these issues I would look at a lift pump before a fuel shim mod IMO

hope this helps
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