Keystone RV Forums - View Single Post

wa5ngp · 10-14-2019, 06:37 PM

Frequent lurker/reader here seldom poster. I'm puzzled that I haven't found any CP4 fuel pump catastrophe stories here. Especially from the DMAX crowd. As most probably know in 2011-2016 dmax switched from a high $ overdesigned cp3 fuel pump to a totally redesigned cheaper cp4. All of this happened as lubrosity of diesel was falling. As a result significant numbers of CP4 fuel pumps have failed in a spectacular fashion taking out whole fuel systems with them. they often happened somewhere beyond the 100K point. If you want to know more check out the duramax forum. there are also class action law suits.

I am just wondering just how bad the problem is. I'm told that those dmaxs with added lift pumps and added fuel lubrosity additives may well survive past 200K. OTOH I hear of stories of people having their trucks cp4s replaced only to have them crater within a few thousand more miles.

Its my understanding that Ford also switched to the cp4. They have a lift pump and that might be saving them. As far as dmax goes they have left Bosch and are going with Denso and now no surprise they also include a lift pump.

Seeing no complaints here makes me wonder about the frequency of the problem UNLESS everyone here buys a new one before they get to the 100K mile point.

10-14-2019, 06:37 PM	#1
wa5ngp Junior Member Join Date: Jan 2014 Posts: 8	no cp4 fuel pump problems? Frequent lurker/reader here seldom poster. I'm puzzled that I haven't found any CP4 fuel pump catastrophe stories here. Especially from the DMAX crowd. As most probably know in 2011-2016 dmax switched from a high $ overdesigned cp3 fuel pump to a totally redesigned cheaper cp4. All of this happened as lubrosity of diesel was falling. As a result significant numbers of CP4 fuel pumps have failed in a spectacular fashion taking out whole fuel systems with them. they often happened somewhere beyond the 100K point. If you want to know more check out the duramax forum. there are also class action law suits. I am just wondering just how bad the problem is. I'm told that those dmaxs with added lift pumps and added fuel lubrosity additives may well survive past 200K. OTOH I hear of stories of people having their trucks cp4s replaced only to have them crater within a few thousand more miles. Its my understanding that Ford also switched to the cp4. They have a lift pump and that might be saving them. As far as dmax goes they have left Bosch and are going with Denso and now no surprise they also include a lift pump. Seeing no complaints here makes me wonder about the frequency of the problem UNLESS everyone here buys a new one before they get to the 100K mile point.