I spent a week banging my head against the wall trying to find a problem.
Machine was running fine turtle to rabbit, but WOT under load picked up a miss. I could hear it, not really bad but it was there. Got to be fuel. Lift pump OK. A few squirts if brake clean around the injectors, no rpm change. Hard lines to the injectors all good. Temp gun to the exhaust idle>WOT = close enough. Everything else checks out. Must be the fuel filter. Has to be.
Nope. No joy
Poking around and wiggle the tiny rubber bypass line between #1 and the thumb valve on the injection pump- fuel starts dripping. Pull it off and behold a little tiny crack. Replace it and it runs like a top.
The crack was on the pressure side after the injectors so it should have been leaking and easy for spot, not sucking air back only at WOT under load.
Machine was running fine turtle to rabbit, but WOT under load picked up a miss. I could hear it, not really bad but it was there. Got to be fuel. Lift pump OK. A few squirts if brake clean around the injectors, no rpm change. Hard lines to the injectors all good. Temp gun to the exhaust idle>WOT = close enough. Everything else checks out. Must be the fuel filter. Has to be.
Nope. No joy
Poking around and wiggle the tiny rubber bypass line between #1 and the thumb valve on the injection pump- fuel starts dripping. Pull it off and behold a little tiny crack. Replace it and it runs like a top.
The crack was on the pressure side after the injectors so it should have been leaking and easy for spot, not sucking air back only at WOT under load.