Hey guys, I just bought an 01 cummins that keeps pulling a code under hard accelleration, it will drive perfectly fine up until about 75-80 percent throttle at which point it loses all power and falls on its face for a few seconds then it will drive fine again. The code it is throwing is p1689 which from my research could be any number of things. This is the only code it is throwing, the truck has a brand new vp44 installed last month. the only mods to the truck are an exhaust and a k&n filter, everything else is stock from what i can tell.

please help lol

 

Try checking the fuel pump relay, also might want to check your fuel pressure coming from the fuel pump to make sure you adequate flow.

 

P1689 is almost always related to the injection pump or transfer pump. Have the shop that replaced the VP44 perform pressure and more importantly, volume test. Teh fact that it only happens during hard acceleration tells me it's not gettign enough volume under load.