About a week and a half ago I had a customer call me with a 2008 GMC that he thought ran out of diesel. Back in the fall I installed an HSP twin kit that required the removal of the stock fuel filter. He wanted to know how to bleed the fuel system without the stock filter. I told him he could disconnect the quick connect line at the rear of the driver's side valve cover to get most of the air out, but he would just need to crank on it to bleed the air out of the high pressure side. He called me back a couple more times asking for more advice as he wasn't able to get it to start. Eventually he decided to just haul the truck out to me. I diagnosed it as a bad CP3.
Rather than installing a stock CP3, he elected to use a CP3K from Fleece. I had no previous experience with one of these pumps, but I am impressed with how well it works. On the biggest tune with a pulse width of 3250 microseconds, it was able to hold an average rail pressure of 25,930 psi with an average regulator duty cycle of 22.6%. The minimum pressure was 24,762 psi and the max was 26,990 psi. The datalog sample was 10.5 seconds long with an RPM range from 2328 to 3435 and an average RPM of 2952. I think it's very impressive considering the truck still has the original 150k mile injectors that are probably showing some slightly elevated return rates from a brand new set of injectors.
Rather than installing a stock CP3, he elected to use a CP3K from Fleece. I had no previous experience with one of these pumps, but I am impressed with how well it works. On the biggest tune with a pulse width of 3250 microseconds, it was able to hold an average rail pressure of 25,930 psi with an average regulator duty cycle of 22.6%. The minimum pressure was 24,762 psi and the max was 26,990 psi. The datalog sample was 10.5 seconds long with an RPM range from 2328 to 3435 and an average RPM of 2952. I think it's very impressive considering the truck still has the original 150k mile injectors that are probably showing some slightly elevated return rates from a brand new set of injectors.
