Salpolit

@fjh had the solution! Checked timing using a boroscope in the test port on the injection pump, found it to be 3 degrees. Engine called for 9.5 degrees, set it to that and the truck runs like new! I appreciate all the help and diagnosis from everyone, just happy to finally have the old dog running good again

Final update: Ran through everything I could, still having issues. Definitely runs way better the harder you run it and hotter the engine gets. When getting on it, noticing a whitish-gray haze until engine is fully hot. I did some research and believe the injection timing on the engine is too retarded as I have all the symptoms of that. Is there any way to advance the timing a degree or two without the Kent-Moore timing light tool?

Haven’t checked yet, I’ll take a look tomorrow to see what’s in there

We replaced fuel filters multiple times, only thing I can think is maybe I have some bad diesel. Running K-100 in it seems to help. Loaded 14 ton in the truck today and with a load on it, it barely does it if at all. Seems to only do it under very light load circumstances. I think I’m going to live with this for a while and hope that running some fresh fuel through the truck will help. The fuel is only about 3 months old and it came out of the same tank as our other fleet trucks. But moisture maybe got into the tanks while the truck sat for the engine swap. I’ll report back when we have a resolution!

Update: Lift pump finally arrived. Changed that and no change. Decided to run the overhead, found most of the cylinders loose but 2 of them were tighter than normal. Adjusted everything into spec and that made the engine run better and eliminate any haze when idling. Still does the misfire though. I took the truck for a drive today and noticed that it only does it when taking off and starting to build boost (or revving it at idle). Once the truck is running down the road, you can lug the engine down and everything and it won’t sputter again until it has a “light load” condition like idling or coasting. I noticed it does it significantly more after coasting in gear. Could this be some type of a stuck valve or wet stacking?

Waiting for the new lift pump to arrive, hopefully Monday it’ll be here. Going to throw that in and see if it changes anything. Fingers crossed!

I have a call in with a company we use for diesel injection services. He told me idle lift pump pressure should be approximately 25 psi and go up from there as RPMs raise. Currently idle is at 18 psi and then when we rev the engine up, the pressure increases slightly but then when it starts stumbling, it goes down towards 15 psi even while the RPMs are up. Once the stumbling clears up, the pressure will go past 30 psi. I’m hoping we are on the right track here, thinking bad lift pump?

The old engine had a Jake on it, this one doesn’t. That makes sense what that solenoid was for, actuated the Jake’s! Totally forgot about that

This is what our current pump setup is. am I missing anything that could affect the timing or anything related to this issue?

No luck! Still runs bad with new injectors. It runs great when holding RPM at any rpm but stumbles, smokes, and backfires a bit when stomping on it. I noticed this solenoid looking thing from a picture I have on the back of the old injection pump on the old engine. Issue is I already sent that engine back so don’t have a clue where it goes/what it does. Would this affect the pump or timing at all?

Thanks guys. Pulled injectors today and wow they were bad. All loaded with carbon and dripping fuel. Hope we didn’t wash down any cylinders too bad! 6 pack of new injectors on order, hoping to have them in by Tuesday next week. I’ll report back how it goes

@JoeH no clue unfortunately. Motor seems healthy, zero blowby and holds 70psi oil pressure when cold and 30 when hot. Was hooked to an Allison in an MR before this so hopefully she had a decently easy life. We won’t see the new lines til Friday so my plan of attack is yank the injectors, check them over, and if they look suspect we’ll just throw a new set in along with the new lines. Fingers crossed!

Thank you. I'm going to check those out hopefully it's something stupid! I'll report back what we end up finding

Hi everyone, We recently installed a new to us E7 mechanical engine in our RD as our old engine bit the dust. The new engine runs fantastic, no blowby or anything. Main issue is when revving the engine up quickly, it will stumble a bit and blow some white smoke but then it will "catch up" and everything will be fine. What is weird is when you go slow revving the engine up, it doesn't do it. Also, when the engine is fully warmed up it barely does it if at all. Only seems to do it when colder and without much of a load on the engine. Other symptoms/potential issues are cylinder 2 & 3 fuel lines are currently leaking out from the head so we are going to replace those lines as well as pull the injectors and install new O-ring kits on them to ensure they are sealing properly. Is there anything else that can cause this? I read on the VMAC I engines the econovance can cause this issue but being that this is fully mechanical without any wires going to the pump I can't see how that is a possibility. What do you think?

Update: 6 new injectors and ran the overhead and she’s back in business!