Okay so I've got a hrvp had it for less than a year, over the summer i have noticed that after you floor it the truck will idle rough for a while and its just been getting worse, not it ides rough every time i warm it up and drive it, It still has lots of power. when it idles rough it kinda hammers sounds to me like the timing is too far advanced. I'm thinking the timing piston is sticking, anyone have any thoughts on this? oh yea i have 1693 code which this pump and the one befor it both threw. I'm running a fass and presures are good.

 

I THINK i know what you mean. After you return the pedal to idle from 3/4-WOT it will idle rough when the engine returns to idle..??
Mine started to do this, it kept getting worse until I replaced my VP44. Someone told me it was loosing prime due to a weak diaphragm.. Hope this is not your case, but it was mine... Good luck

 

Mine did the same thing, and it was a 7100, changed it out no problem for several years

 

I got busy after work today, cracked injector lines to listen for a diff in rpms, noting really showed up so i got out the temp gun and found that #1 was a lot colder than the others so i pulled that injector and took it apart, had to pull the pintle out with pliers lol, worked it for bit but it was still too tight. so i tryed putting a stock pintle in, no luck as the 90hp injectors bore is bigger around the pintle, but i tryed it anyhow and it wouldn't fire at all. So i put a stock injector in the hole and it ran jsut roughf but i expected that. so i put all my stock injectors back in and fired it up, had a bad knock on #1. sO i swtiched the injector from #1 to #3 still have a knock so i reved it up for while and it went away. It was a bit of monkeying around but its working good now. I just really miss the power thoose 90hp injectors gave me.