lb7 injectors

DAVe3283

Heavy & Slow
Sep 3, 2009
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One indication of a bad CP3 is the inability to maintain rail pressure. But worn injectors with high return rates can cause that too. But yeah, the CP3 might be bad, and sounds to be at least worn. Might be worth replacing it now.

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Casey

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Sep 12, 2014
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my goal is to replace all the things that could be bad while im in there. yes could be wasting money but ill know its done. sure there is cheaper stuff out there A.K.A Pensacola but i dont want to go there everyone says dont... im going with LDS stock injectors there stock cp3 also getting arps and headgaskets from them getting my filter head rebuild as well. going to buy a water pump and weld it myself also doing all rubber fuel lines. doing bigger turbo horn, s&B cold air intake and 4 inch exhaust, also getting egt probe for my cts2. dont think im going with new injector lines just going to clean mine. i know the truck was at gm at 98k miles but they only replaced the bad once. anything els i should do while in there? think that stuff should give my truck more life and hopefully a little more power
 

THEFERMANATOR

LEGALLY INSANE
Feb 16, 2009
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I wouldn't replace the CP3 at this point, especially if the budget is tight. Unless you have tested and found it to be bad, of course.

IMO anything less than 50% over is a waste of money. Stock injectors can run 500-600 HP just fine. If you want more than that, I'd go straight to 50% over or bigger.

Lots of people recommend SAC injectors because we believe they will last longer. However, SAC injectors on the LB7 are so new, their longevity isn't really proven yet. No one has had one fail, but we don't have enough miles to expect a failure either.

If it were me, and my budget was really tight, I'd get a set of stock VCO injectors from LDS. If you can swing it, skipping the CP3 and upgrading to SAC injectors might be worth it. The smallest SAC injectors are about 50% over, and you might need an EFILive tune with those.

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The dyno numbers and flow sheets for the 45 overs suggest they are actually only 30 overs. Kennedy was calling them 30 overs when he 1st came out with them, then the others came out with them and called them 45 overs, so he changed his description(his words, not mine). His dyno testing showed a 70HP gain by just putting in the 45 overs which would be on par with a 30 over injector. All the descriptions also say to get a 60-80HP increase, which is what a 30 over gives normally. I know too many here recently have had the VCO's fail in well under 50K miles, I was really hoping for 100K out of mine, but only got 71K miles. I'm sticking with a stock bottom end, so the smallest ones I can get will work fine for me, I just know I'm not rolling the dice on VCO's again. All the improvements have pretty well taken care of return rate problems in LB7 injectors, so if SAC's correct the nozzle/blue smoke problem, then they should be good to go for awhile(at least I'm hoping). I know kennedy has been selling them for a few years now, and the last posts I read from him this year said he still hasn't had any failures with them.
 

Casey

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Sep 12, 2014
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Ya but Im not buying injectors then turning around and dumping another 800 on efi live so change my settings I don't have the money for that.
 

Casey

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Sep 12, 2014
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If there was another way around getting say bigger injectors and having to get efi live I would. But my truck has a stock trans I don't plan on going big power so I don't really need efi live..
 

THEFERMANATOR

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Feb 16, 2009
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You can run the 45 over SAC's on stock tuning, but no bigger until you build your trans. Many are running them on stock tuning, just take it easy towing as they add in the 60-80 HP range which is fine empty, but pushing it towing. But you should retune for ANY oversize. So unless you're going with stock injectors, budget in tuning in all honesty.
 

Casey

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Sep 12, 2014
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Is there any other way to tune for bigger injectors without efi live. Pretty much I would buy the v2 just to run bigger injectors. That's $800 extra on top of the $2600 or so for injectors. With everything else I have to do i can't afford to do that.
 

dordtrecht5

Regular Cabs Rock
Jul 21, 2009
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Is there any other way to tune for bigger injectors without efi live. Pretty much I would buy the v2 just to run bigger injectors. That's $800 extra on top of the $2600 or so for injectors. With everything else I have to do i can't afford to do that.
You don't have to buy a V2 to retune. Just about of the guys that are known can put a preloaded tunes on your ecm. You ship them yours, they ship you a tuned ecm. You buy the tuning and a dsp5 switch. $350 for great tuning of which you can't buy that kind of tuning with a box Tuner. Easy peazy.

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Casey

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Sep 12, 2014
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You don't have to buy a V2 to retune. Just about of the guys that are known can put a preloaded tunes on your ecm. You ship them yours, they ship you a tuned ecm. You buy the tuning and a dsp5 switch. $350 for great tuning of which you can't buy that kind of tuning with a box Tuner. Easy peazy.

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But can I still run my edge evolution when they do that?
Or would it be useless after that. I'm in Oregon I don't know if there is any decent shops around me.
 

WolfLMM

Making Chips
Nov 21, 2006
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Catman on here may be able to help you out in the tuning department! He is in Oregon.
 

Casey

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Sep 12, 2014
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So i guess now the question becomes if i were to go with the SAC injectors from LDS, if i send my ECM in to get tuned could the also change it to run the bigger injectors correctly. is it worth going bigger on stock turbo will the gains be worth it. or should i just go with stock sticks and build my trans and do turbo by the time id get those done id probably need new injectors agine. i dont even actually know if i need injectors i dont have white smoke my balance rate are within spec but i im only getting 14mpg and have fuel limp mode quit often. was just going to do them while doing my head gaskets just to know there done and not have to worry for awhile.
 

dordtrecht5

Regular Cabs Rock
Jul 21, 2009
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So i guess now the question becomes if i were to go with the SAC injectors from LDS, if i send my ECM in to get tuned could the also change it to run the bigger injectors correctly. is it worth going bigger on stock turbo will the gains be worth it. or should i just go with stock sticks and build my trans and do turbo by the time id get those done id probably need new injectors agine. i dont even actually know if i need injectors i dont have white smoke my balance rate are within spec but i im only getting 14mpg and have fuel limp mode quit often. was just going to do them while doing my head gaskets just to know there done and not have to worry for awhile.
What I would do:

SAC 45%
ECM tunes and a dsp5 switch and have the tuner build your tunes with those sticks. (They will ask you what work you have done to your truck.)
Save as much money as you can to build your trans as soon as your able.

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Awenta

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Sep 28, 2014
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What I would do:

Get someone to properly diagnose your truck.


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DAVe3283

Heavy & Slow
Sep 3, 2009
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What I would do:

Get someone to properly diagnose your truck.


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^ This.

It sounds like you are replacing both injectors and head gaskets when it might not need either. From what you've said, it might need a CP3 and nothing else.

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WolfLMM

Making Chips
Nov 21, 2006
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Eh, if I doing head gaskets I'm doing injectors too (unless they are brand new) we all know that lb7 injectors have no guarantees. I think he is money ahead to replace both at the same time. Blowing coolant out the overflow is a pretty good indication of blown HGs. However a simple hydrocarbon test of the coolant will confirm. It could also be a lifted cup... which I why a say replace it all and be done with it. Do it once. Jmo
 

Casey

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Sep 12, 2014
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well truck has 157k on it, dealership did some of the injectors under warranty not all so there is 157k on some of the injectors along with everything else. i was now told to run sac 45% overs i don't need a tune is that true? if not true can i still use my edge evolution cts2 on stock for gauges if i get a tuned ecm? i was going to go with the lbz cp3 but that needs tuning to run as well can they tune the ecm for that as well if i do get it tuned. i emailed www.ridgerunnerdieselperformance.com but have not got a response i don't know who else does ecm tuning.
 

Awenta

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Sep 28, 2014
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Tony will take great care of you and it will be done right. But you should get an autocal from him instead


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Casey

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Sep 12, 2014
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i need tuning to run bigger injectors and mabye for lbz cp3 autocal cant do that would have to buy a v2 but my funds don't allow me with everything else i have to buy.