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lift pump pressure..

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I just put on a 6.7 cp3 (used from motoman006) and it works great. My question is, on my 5.9 cp3 I had 21-23 lbs pressure and on the 6.7 it is 25-26. Is this normal?? How much pressure should I be running?? I am running a stock lift pump and a holley blue without regulator. (I know I need an airdog or something, just cant afford it right now).
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i have heard over 27-30k for a long time is not good for injectors, i know someone will add in with more info than i know.
 

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Discussion Starter · #3 ·
I am sorry for the confusion, it was the lift pump pressure that I was stating :doh:
 

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What are you running for a LP? If its the stock LP then your gauge is broken as it will not really exceed 8-9, (some hit 11).. But thats about all.
 

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Discussion Starter · #5 ·
What are you running for a LP? If its the stock LP then your gauge is broken as it will not really exceed 8-9, (some hit 11).. But thats about all.
I have a Holley Blue in line on the frame, and then the stock lift pump. My stock lift pump was at 9psi until WOT then it was at 1psi.
 

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I have a banjo fitting with gauge line tap on the fuel "in" line at the cp3. I had the same exact fitting on the other pump. This is why it is odd to me :confused013:
 

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It could be that the 6.7 CP3 returns less fuel to the tank, thus more resistance and higher pressure. This would be one way they make more hp on the same LP as the 5.9.

I would turn the pressure down a bit. 30 is about all you want to the OE canister before it starts to leak, and the CP3 really only needs 15 at most.
 

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I'm with AH on this, I bet the new CP returns less fuel, with two pumps running you are seeing higher pressures. The first thing I would do is confirm the gauge accuracy with a mechanical gauge. Assuming the gauge is right, I would add a regulator and dial the pressure back to about 15 PSI at idle. I bet running LP pressures as high as you are is not good for the CP3.
 
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