Dropping rail with 3 CP3s?

Awenta

Active member
Sep 28, 2014
4,090
2
38
CT
Did it run before and this is a new issue or are you just dialing it in for the first time?

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juddski88

Freedom Diesel
Jul 1, 2008
4,656
120
63
Chesterfield, Mass.
Thought about that but I have ran modified pumps with stocker pumps in dual setups without issue.


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I mean, you have two pumps working (pulsing) fuel at presumably the
Same rate, then you have another pump pulsing fuel at a different rate (a pump mind you that needs to be timed in its original application) whose check valves, for lack of the correct nomenclature offhand, may not be able to overcome the pressure pulses of the other two pumps since it is timed and designed differently. I don't have any first hand knowledge of how well dual cp3 kits have been working on LMLs these days with the stock pump in the valley, but I have heard they didn't fair too well. Maybe a good question for Brayden or the bosch experts.
 

dirtydmax

<---up shit creek
Sep 1, 2013
1,091
4
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46
muskoka,Ont Canada
I had a simualar prob last fall and never did pin point the issue before loosing the mains,My setup was nowhere near as big as yours is but i also use a fingers triple cp3 controller but 3 lbz pumps.does this look familiar? https://www.youtube.com/watch?v=nuJ71SJHjew&feature=youtube_gdata_player had 1 pump explode and i think another on the way out causing the sputter but?Interested as to what is causing yours.
 
Last edited:

DPC

Member
Jan 2, 2012
323
1
18
Adams, TN
Yes same issue.

I had a simualar prob last fall and never did pin point the issue before loosing the mains,My setup was nowhere near as big as yours is but i also use a fingers triple cp3 controller but 3 lbz pumps.does this look familiar? https://www.youtube.com/watch?v=nuJ71SJHjew&feature=youtube_gdata_player had 1 pump explode and i think another on the way out causing the sputter but?Interested as to what is causing yours.

Yes, that is exactly what mine is doing! Initially I noticed it around 3k right where my pilot injection shuts off. I extended my pilot out to 4K and that helped at light throttle but did nothing at WOT.
 

DPC

Member
Jan 2, 2012
323
1
18
Adams, TN
Did it run before and this is a new issue or are you just dialing it in for the first time?

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Dialing it in for the first time. The truck has gone through so many changes its hard to pinpoint the problem. I thought about saying the heck with it and putting twin 12mm Exergy pumps on it but that is a 5k bill I really don't want to mess with right now.
 

IOWA LLY

Yes, its really me
Feb 23, 2007
2,275
4
0
Why don't you try pulling pulse width back first. If you can maintain rail pressure at something reasonable (say 1400 us or so) then you can work out the problem from there...

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DPC

Member
Jan 2, 2012
323
1
18
Adams, TN
Why don't you try pulling pulse width back first. If you can maintain rail pressure at something reasonable (say 1400 us or so) then you can work out the problem from there...

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Yes, that is where I am going to start... I also have two spare PPE controllers I thought about hooking together to test.
 

dirtydmax

<---up shit creek
Sep 1, 2013
1,091
4
38
46
muskoka,Ont Canada
Yes, that is exactly what mine is doing! Initially I noticed it around 3k right where my pilot injection shuts off. I extended my pilot out to 4K and that helped at light throttle but did nothing at WOT.

Shortly after that vid the valley cp3 granaded and i think damaged a 2nd as well as sending shrapnel to the new injectors hanging 2 of them.That was an expencive adventure but i hope yours stays together!
 

DPC

Member
Jan 2, 2012
323
1
18
Adams, TN
Shortly after that vid the valley cp3 granaded and i think damaged a 2nd as well as sending shrapnel to the new injectors hanging 2 of them.That was an expencive adventure but i hope yours stays together!

That's horrible! What do you plan to change? I am curious as to how Yellow Jacket has his pumps setup.
 

Awenta

Active member
Sep 28, 2014
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CT
But the cp4s are timed aren't they? I personally wouldn't risk running one.

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DPC

Member
Jan 2, 2012
323
1
18
Adams, TN
But the cp4s are timed aren't they? I personally wouldn't risk running one.

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The CP4 I was referring to is NOT a CP4 pump it is a CP3 from a 2010 6.7l Cummins, for some reason I thought the newer 6.7s had CP4s. I need to edit my first post... sorry for the confusion.
 

ikeG

Oughta Know Better
Apr 19, 2011
2,465
147
63
Western PA
www.facebook.com
We were going to run 3 sportsmans but im glad wehrli talked me out of it. He said tuning can be an issue as well as controllers. And he has had lots of experience with trucks of matt's caliber(yellow jacket) built from the ground up in his shop. Good luck
 

juddski88

Freedom Diesel
Jul 1, 2008
4,656
120
63
Chesterfield, Mass.
The CP4 I was referring to is NOT a CP4 pump it is a CP3 from a 2010 6.7l Cummins, for some reason I thought the newer 6.7s had CP4s. I need to edit my first post... sorry for the confusion.

The FCAs on the cummins regulators are scaled quite a bit different than duramax ones. But it is better to hear that you are running 3 true cp3s :D
 

GMC_2002_Dmax

The Still Master
Change your scaling to this

1800.000000
1648.500000
1488.750000
1326.750000
1215.750000
1159.000000
1121.500000
1088.000000
1056.000000
1020.000000
1000.000000
993.000000
986.000000
930.000000
878.000000
826.000000
770.000000
000.000000
000.000000


Then go to table B1009 and set to "0" as well.

That will force the regulators to go wide open, essentially no real control over the CP3's/CP4's so you should get the max rail psi out of it.

They also have a set of billet rails now, supposedly flow way more fuel and uses LLY #2 and #6 Injector lines and have a larger cross flow rail between both banks IIRC.

Good Luck
 

Yellow Jacket

WannaBe Sled Puller
Feb 11, 2009
917
0
16
Waterloo, IA
Change your scaling to this

1800.000000
1648.500000
1488.750000
1326.750000
1215.750000
1159.000000
1121.500000
1088.000000
1056.000000
1020.000000
1000.000000
993.000000
986.000000
930.000000
878.000000
826.000000
770.000000
000.000000
000.000000


Then go to table B1009 and set to "0" as well.

That will force the regulators to go wide open, essentially no real control over the CP3's/CP4's so you should get the max rail psi out of it.

They also have a set of billet rails now, supposedly flow way more fuel and uses LLY #2 and #6 Injector lines and have a larger cross flow rail between both banks IIRC.

Good Luck

This will show if it is a supply or flow issue....
But in my experience with 3 pumps, (2 are 9.8mm lb7/LLY stroker pumps)(1 is a 6.7 pump) it will blow a check ball out of the injector from over pressure. 3 stock pumps he may be OK though.
 

x MadMAX DIESEL

<<<< No Horsepower
Dec 30, 2008
7,535
1
38
34
Lexington, Ky
You'll also force close off injectors, depending on if you have a way to log the actual actual pressure versus the desired. Check balls suck and they need to be welded closed


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