Alright I've got a 92 W250 that I installed a 95 p pump engine out of a f700 medium duty truck completely rebuilt engine new .20 mahe pistons new colt cam big stick 200 HP ducky fuel injectors head studs 0 fuel plate 4k govoner springs 64 mm turbo .10 head gasket injection pump was rebuilt to stock specs head was reworked with new guides, seats ,and seals it has fass 220 fuel system problem I'm having is the truck has a sorta miss or pop out of the exhaust its really bad when cold but kinda clears up when hot put its still noticable timing on the pump was set at 18 degrees also I already changed the overflow valve on ij pump and injectors with no difference truck runs excellent no power loss not a lot of blow by I'm kinda lost on this one should I check compression ? I dont have a fuel pressure gauge set up yet could it be delivering too much fuel to the engine ? Another person said valve seat but the head was redone ? I'm lost all help would be appreciated

 

Only thing I can think of is 18 degrees too much timing for your setup?

 

Yea that was the next thing I was going to try and drop it to 16 but I've been told people run 18 all the time with no issues

 

Does it miss under load or unloaded? Any white smoke when it happens? Those are pretty big sticks and probably won't drive very nice until you get some good heat running through it. Won't help if the spray is out of the bowl too, good match on piston top and injector spray?

 

No it doesn't miss under load or while driving down the road I had 140 HP injectors in there sounded the same I also have 022 delivery valves but had stock ones in there did not make a difference

 

No white smoke the pistons I installed were mahe factory pistons they just have a bigger bowl like a marine piston I called pure diesel power and they said regular injectors should be fine

 

Bump.. Really need some help

 

So when does it miss? Just hitting throttle in neutral? I consider that normal for 12v's. If at idle then...time to dig deeper. Make sure you're not sucking air into fuel lines also.

 

It does it idleing you can stand out beside the truck and hear it you can rev it up and hear it until about 1300 rpm then it kinda goes away when the engine warms its still there but barely noticible you can see the whole truck shake when standing beside it the engine only has around 100 miles or so on it one person said it could be a ring not seated ? Said I needed to drive it? also it has a brand new fuel system on it fass 220 spray either on all fuel lines truck don't rev up or anything like there is a leak of any sort

 

I'd guess try a re torque on head bolts/studs and check compression next. Check valves etc at same time, rule out anything easy. I'm not sure about a slippery ring causing the popping/missing with no smoke but I don't build motors for a living either. Also assuming you have checked fuel pressure new system or not.

On second thought try cracking one injector line at a time while idling to see if there is little-no change on any cylinder.