erratic fuel pressure dual cp3

isudiesel

New member
Aug 23, 2006
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We have ppe dual cp3 set up with a big pump in the valley and a stock pump on top on our lbz. 60 exergy injectors. Top pump is fed from t after the lift pump. We are seeing fuel pressure dancing from 18000 to 29000 above 3200 ish rpm. We have tried to tune it out of it, numerous regulator combinations, cascade valve, etc. Any thoughts?
 

blk smoke lb7

<-----Lots of green $
Nov 8, 2010
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belvidere,ill
What motor?Could be a fprv if its lb7,could be injectors relieving.I had a problem with my injectors 2 years ago relieving at higher rpms and it would vary.New injectors and the problem was solved.
 

isudiesel

New member
Aug 23, 2006
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Thanks for the input.
I am still running it throught the stock test port and fuel supply pressure remains above 8-10 psi consistently.

This is on an lbz. No fprv. Using a race valve. Maybe its time for the big injectors.
 

isudiesel

New member
Aug 23, 2006
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Joshh
Any more thoughts on the tuning? This has been ongoing since last year. Nick looked at it back then remotely, but couldn't get it smoothed out.
 

isudiesel

New member
Aug 23, 2006
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Fuel pressure tables are set back to stock. Tried changing b1015 but does not seem to make any difference.
 

isudiesel

New member
Aug 23, 2006
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I am running out of options short of new pumps, injectors, etc. Do you have an idea of what the issue is? Have you seen this before with a modded and stock pump?
 

Dan@PPE

Diesel Enthusiast
Aug 8, 2006
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So Cal.
Yes I have seen the issue before (a few times). Almost every time it has been related to the tuning/the tuner..
 

JoshH

Daggum farm truck
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Feb 14, 2007
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Texas!!!
B1058
B1057
B1073

Make sure the values in these cells/tables are at least 200 or higher (only the top 2 rows in B1057 need to be changed, but it won't hurt to change them all). If that doesn't fix it, you will need to play with the PID control tables.
 

isudiesel

New member
Aug 23, 2006
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Thanks for the input josh. Will this get the pressure above the controllable level for the ecm and leave the regulators wide open?