I just installed my new IP and 5x.014 injectors and after cranking the truck it definitely has a new sound at idle. To me it sounds like a lope but my friend thinks its a fuel knock. The sound goes away as soon as you bring it up from idle. The pump is basically stock with a 3200 spring and fuel pin. II built the pump and i did not change anything yet. I set it with a hair of timing advance, just barely over the line from the factory pump. I just installed it where my afc boost tube was already bent to from the previous pumps timing advance. The pop pressure on the injectors were set at 255 bar.

I am running the same set up on my 4bt but didn't notice this same sound on it. Of course that motor has no harmonic balancer and rattles like crazy anyways.

I figure i can adjust it out with timing but am curious if that kills the benefit of the increased pop pressure.

 

A diesel shouldn't lope. What's your idle RPM

 

No tach so I'm not sure on idle rpm. It's definitely lower than my old pump was but i had it idled up a little bit.