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I just had my lmm deleted and tuned and i have noticed sometimes when i really get on it it will like loose power for a second and then pick back up. Mainly when it put it in level 5. It kind of seems to me like if not getting enough fuel. I changed the fuel filter about 2 oil changes ago. Is it time too change it again maybe?

Lmm Guy
 

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Level 5 of what? You may not be able to provide enough fuel on a high tune with a stock filter housing setup..
 

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50gph stock filter.....unlikely

When you start stressing the aging fuel system with an ultra hot tune.....you're gonna come up short, leaks/kinks/etc, not just one thing.
 

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Lmm Guy
Referring to post 2.
Post edit, more added.

Checking pressure at the filter head with an adapter for the bleed port, shows whether your filter is restricted...instead of just guessing and changing it.
 

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Over about 100-120hp tune, you will probably start to see the rail draining and loss of pressure. If you get a code, it will likely be a low rail pressure. Most people who run those bigger tunes install a lift pump to prevent the loss of pressure and prevent that low spot in acceleration. Usually feel it at higher rpms.
 

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You may find that even with a lift pump that the stock cp3 can’t hang. If you have a cts2 try setting 2 gauges up to watch rail pressure. One set to desired rail pressure and the other to actual rail pressure. Run the tune that doesn’t drain the rail lower than the desired pressure untill you get a better flowing pump.
 

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I got a 2008 and mine did the same thing. I almost thought it was transmission issues. A guy at a diesel shop tried telling me I needed injectors too.

Your cp3 is fine. They can hang for awhile in my personal experience and opinion.


Once I started turning mine up passed 120hp on my tunes and started noticing what your going through. It’s two things.

First thing is you have a fuel pressure relief valve on the back of your fuel rail driver side. Our injector system is a Bosch I think 30k pound rated. So don’t quote me but once your start hitting 27k there is a spring in that valve that opens and you get fuel pressure loss. I think stock no tune lmm will push 25-26k psi. Once you start feeling this and it pops off the first time it will start happening more frequent and easier now this is in my experience. Mine got bad enough I noticed it a little bit on a 75 hp tune. And it doesn’t always put you in limp and throw a code. But like I said it will get worse. Go on any diesel site or google fuel race plug or fuel rail plug. It’s simply how it sounds it’s a billet plug instead of a FPRV. Don’t worry this doesn’t mess your truck up I’ve never heard of that happening.

The next thing is a lift pump. Google it up they’re pretty simple. If your gonna run higher then 75-100 hp tune you will need one. I’d buy one with filters because it only helps. If your fuel isn’t leaking through the FPRV your running out of fuel because the tune is simply asking for more then your stock cp3 can handle. Getting a lift pump helps your entire fuel system and always makes sure your motor has the fuel demanded. I went with an airdog but other brands are great too.

All in all my pump cost me 6-700 and the plug was 40-45 bucks and I never had a fuel issue or rail issue every again.

I pushed my stock cp3 and injectors to 600hp or about along with a rail plug and a lift pump and still never had fuel issues. Hope this helps.

I just had my lmm deleted and tuned and i have noticed sometimes when i really get on it it will like loose power for a second and then pick back up. Mainly when it put it in level 5. It kind of seems to me like if not getting enough fuel. I changed the fuel filter about 2 oil changes ago. Is it time too change it again maybe?

Lmm Guy
 
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