I have a 04.5 2500hd duramax that I just replaced an Injection Pump from Industrial Diesel that has 45% more volume and added a FASS Lift Pump. I did this because my original CP3 pump was going out and kept giving me P1083 codes. I got the truck running yesterday, fixed all the water leaks (gotta love the o rings) and now I keep coming up with a P0089 DTC for high fuel rail pressure. I called Industrial Diesel and they told me to cut one coil off the pressure spring on the FASS lift pump, I did that and I still have the P0089 code, every time I erase the code it comes right back with in 3-5 minutes

This truck is purely stock, it has just the modified CP3 pump and lift pump no tuners or anything like that, I have 4" straight pipe exhaust from turbo back.

Can anyone guide me in the right direction on how to fix this code

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Also have the PPE High Flow CP3 Pump Feed Line Kit

 

After talking to the people at PPE (great company) and Industrial, found out that the Fuel Rail Pressure Regulator either is bad or has something stuck in it. I took it out cleaned it out but still have the problem just not as bad. Industrial is sending me a new regulator.

 

Ya, could be the regulator. I don't know enough about the modified pumps to know how they could/would jack with the stock settings. If they do at all.

 

Finally got it figured out last week, the fuel psi regulator on the pump itself had something stuck in it, I put another one on and it fixed the problem right away. I am playing around with the lift pump pressure settings to get it just right, but the modified CP3 makes a hell of a difference when it comes to power, it gets good power compared to stock from idle but from 65- speed limiter, it pulls hard. Next is the ppe tuner and 5" exhaust and the LBZ air box.

Thanks for the reply!