Fass 150

05chevy

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I have a fass 150 on my 12 valve and was wondering if I could put it on my duramax? Will it work or have to much pressure? Or do they all have around 10 psi?
 

MACKIN

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You'll need a regulator if there isn't one on there or with it. Otherwise with the exception of plumbing and electrical to yur need it should work fine
 

JoshH

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You can probably call FASS and get a new spring for the pump to lower the pressure, or they may be able to tell you how to modify your existing spring if possible.
 

05chevy

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OK I have a ppe on my dmax but would like to put the fuel air seperater on it. Just wanted to make sure I could use the pump
 

duramaximizer

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The fass, is fine even without a regulator I think, you just have to have EFI Live to turn your Fuel Pressure Regulator down on the CP3, otherwise you will set a P088 which is Fuel Rail Pressure too high.
 

05chevy

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How will fuel pump pressure make rail pressure be to high? Doesn't the cp3 Turbo low pressure fuel into high pressure fuel? Just wondering?
 

JoshH

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A FASS 150 that is setup for a 12 valve Cummins is going to be running much higher pressure than a FASS 150 that is setup for a Duramax. Like I said earlier, you're going to need to modify the pressure regulator spring or get a new one.
 

duramaximizer

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How will fuel pump pressure make rail pressure be to high? Doesn't the cp3 Turbo low pressure fuel into high pressure fuel? Just wondering?

Based on how the CP3's works, it actually vaccums fuel from the tank up to the CP3 and pressurizes it. The CP3 has its own regulator. Based on how far open the regulator is (20%), the computer expects to see a certain rail pressure at idle (7000 psi for example). But after you add a Fass system adding 50psi of supply pressure to the CP3, your truck and the computer is still commanding the CP3 regulator to have to open about 20% to get to 7000psi rail pressure. But now all of a sudden at 20% opening, the CP3 is making 8000 psi rail pressure.

The computer then based on a rail pressure sensor says, "Hey something isn't right here and sets a code and a service engine soon light."

So until you adjust the Fass down to say 25psi with a spring, you will get a service engine soon light. (Unless you have EFI Live.)


FYI I believe that the dodge fuel lines are 3/8inch and duramax are ~1/2" so you will need some different fittings from your local Napa.
 

05chevy

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ok thanks for the input. im still learning about the hole cp3 pressures and tuning with efi live. thank you