1900-2200 rpm studder 1000hp pull truck

blackmega3500 said:
Which came first the shudder or cp3?

Notice a trend here...... both of yall have the 12mm exergy.



Amen!

I remember my old dragon slayer cp3 on my other truck would have a slight pulse til rpms increased. Once it was 2k plus it was just a matter oh holding on.

Todd @ TC diesel has his biggest CP3 available for race/pull applications that's so aggressive it's only designed to spin high rpms, otherwise it's not something wanted for the street.
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I put the truck together at the end of last year. I just started driving it. and noticed the break up. I did however pull the return line off the back of the head and put it in a bottle. let the truck idle for a bit and it filled a Gatorade bottle. I'm pulling the injectors now and changing the cross tubes.

GRotman said:
Did your tuner rescale the current profile for the fca?
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I can only imagine he did. Hopefully hell chime in soon.
 
GRotman said:
Did your tuner rescale the current profile for the fca?
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So question....

When let's say an FCA that comes from a large cp3 such as a 12mm+, what should a user do when there's signs of an FCA going out? One would imagine replace from supplier, or is a drop in cummins FCA acceptable? Think I know the answer, but just curious.
 
blackmega3500 said:
So question....

When let's say an FCA that comes from a large cp3 such as a 12mm+, what should a user do when there's signs of an FCA going out? One would imagine replace from supplier, or is a drop in cummins FCA acceptable? Think I know the answer, but just curious.
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You can always use a drop in Cummins FCA, you may loose some output depending on whose cp3 you are running.
 
mikmaze said:
manual or auto trans?, if auto, how aggressive is the converter?
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Auto trans. 2200 stall converter.

Why is there so much fuel coming out of the return on the back of the head? bad injector? I replaced the crossover tubes, still the same result.
 
Post a video of the fuel return, if you can.


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There's a test you can do to see if the injectors are returning too much fuel. Do a google search it's pretty simple all you need is a mixing cup that reads ml


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mikmaze said:
manual or auto trans?, if auto, how aggressive is the converter?
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STROKETHISF350 said:
There's a test you can do to see if the injectors are returning too much fuel. Do a google search it's pretty simple all you need is a mixing cup that reads ml


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Just went and tested it. According to the post I followed, under 180 ML is passing. I am under 180ml. so the return rate is good. Now I'm back to square one with this issue
 
So why is it nobody else is thinking it has to do with the large cp3......

Honestly your pointing him in the wrong direction as being this is an rpm specific issue that more than likely the cp3 fueling and the tuning map are causing this problem.
 
blackmega3500 said:
So why is it nobody else is thinking it has to do with the large cp3......

Honestly your pointing him in the wrong direction as being this is an rpm specific issue that more than likely the cp3 fueling and the tuning map are causing this problem.
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the only reason I don't think its the tuning is because even without a tune the truck still does it, its just less severe.
 
Foxrider12390 said:
the only reason I don't think its the tuning is because even without a tune the truck still does it, its just less severe.
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No definitely not tune, that just makes the fuel map more aggressive. Meaning the demanded RP is greater sooner which is why the surge is more pronounced. How old is the pump, was it ever run with rail too low, how's the supply pressures and lift pump health....
 
blackmega3500 said:
So why is it nobody else is thinking it has to do with the large cp3......

Honestly your pointing him in the wrong direction as being this is an rpm specific issue that more than likely the cp3 fueling and the tuning map are causing this problem.
Click to expand...

blackmega3500 said:
No definitely not tune, that just makes the fuel map more aggressive. Meaning the demanded RP is greater sooner which is why the surge is more pronounced. How old is the pump, was it ever run with rail too low, how's the supply pressures and lift pump health....
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Lift pump is a fairly new replacement air dog 200. I put a gauge on it today. it is now set around 18psi. When I get to 2k rpm the gauge begins to fluctuate between 17-19.
 
Went through everything at once (injectors, cp3, ported fuel rail from TC Diesel).

The surge doesn't happen in my stock or tow tune...so I'm thinking its tune related. No idea though. Like OP it's at around 2k rpm and I can watch my fuel rail gauge bounce around.

Todd at TC Diesel told me the same thing, that the 12mm would have engine load vs application issues. Thinking about throwing the spare 10mm over it and never again worry about fueling haha.
 
Poulina said:
I have a stock lift pump that stays at 10psi btw
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Be careful to not dump too much fuel with the 12mm as your fuel psi can drop quickly and the pump will cavitate and burn it up. Ideally your fuel psi should be no less than 18.
 
Good to know! Funds kinda in the way right now after basically a completely new fuel system haha
 
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