hey guys got a question...my buddy put evil twins on his truck 2 weeks ago. bottom pump 33% mod, top pump his original stock pump that sat in garage for almost 2 years. anyway, 1st pull he blows freeze plug out of top pump..metal shavings and what not....so he replaced top pump with duramax cp3 and halfway down track with sled he started spraying fuel everywhere. we found it was leaking from the rail pressure sensor that was relocated from rail to the back of the top cp3. between the "big" nut (fitting) and the "skinny" (nut) fitting... so my question is, why did this happen? not tight enough? too tight? bad threads? any suggestions or thoughts would be appreciated! thanx guys!

 

also, should the return line that is bolted to relief valve return back into top pump? someone...anyone?

 

First, the rail pressure sensor needs to go back to the rail where it belongs. If you used a dual feed approach as opposed to linking the two pumps together and feeding from a single point and therefore do not have a port for the sensor, then contact T&C diesel for a 5 way fitting that provides more ports and then you can properly mount the sensor.

While you are there at T&C, also check out the dual relief valve system. It is advisable when running dual pumps. (Think one valve for each pump so the flow volume is matched and adequate to the task)

The return line should "Y" into the return line from the bottom pump and that returns to the tank, not back to the pump.

The answer for the leak though is a poor fit for the sensor to the cp3 (never heard of anyone doing that before; where do you have it?). A copper washer may be needed for proper seal. The cp3 is certainly not made to hook to the sensor though.

 

yes i believe he talked to that guy today at t&c.. he told about putting the sensor back in the rail using that adapter...so i guess hes ordering that kit...he had it installed in a local shop and we dont think they knew exaclty what was going on...so now we just doin it ourselves..thanx for the help

 

Todd at T&C is a top flight guy and will steer you right and always willing to help.