7.3 idi rough running and blue smoke

MaterIDI

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I have a 1993 7.3 idi I'm building and got it running after it had sat since around 2015. Has 240k miles. I had issues with it rough running and blue smoking so I put a set of injectors from Pensacola Diesel which was dumb on my hand and a set of return lines from Russ. It ran perfect for about 2 starts and went back to what it was doing but even worse. It shakes very bad and blue smokes and the oil started smelling like diesel so I have quit running it. Should I swap another set of injectors from a good place in it? Any thoughts on whats wrong?
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Nero

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Take those paper weight of injectors out and get a good quality set from R&D, Moose, or CDD to start with. Sounds like bad injectors.


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MaterIDI

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Take those paper weight of injectors out and get a good quality set from R&D, Moose, or CDD to start with. Sounds like bad injectors.


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IDIBRONCO

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Take those paper weight of injectors out and get a good quality set from R&D, Moose, or CDD to start with. Sounds like bad injectors.
Sounds like a bad fuel pump, they can leak fuel into your oil pan.
I think it's a combination of both of these. Once the engine has been running for a while, leaking return lines or o rings won't cause rough running or blue smoke. Air can't get into the system while the engine's running because there's pressure here, not suction. The only other thing that you changed was the injectors. That's a clue as to what changed, although only for a short time. You may need an injector pump as well since it and the injectors wear at the same rate. I also assume that you saw someone online who claims that just changing injectors will fix your running problems. Those are the type of people who I don't pay attention to because they are either misinformed themselves or they just don't have enough knowledge to give others advice. The smoke and rough running may have only been a timing issue in the first place. I'd recommend looking into that if your new, quality injectors don't fix the running problem.
Like Kdo98 said, a lift pump can have a bad diaphragm that lets fuel into your oil pan. It's possible for that to happen and your engine still runs fine. Another place where fuel can get into your oil is from an injector pump, but I don't think that it's a very common issue. I'd try a lift pump first.
 

Turnshredder

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Have you correctly checked your timing with a timing light ? I wouldn't spend any money on any more parts until you do that. An IDI motor that is out of time will smoke and run rough, even if it has new injectors or a new pump. They go out of time, I've read on here they need to be checked about every 30,000 miles. You may have to invest in the correct timing tools and most Diesel mechanics aren't going to know about this anymore. Do a search on here, there is some good IDI timing articles.

Blue Smoke is usually oil though, and you said it was running good for a bit, might want to do a compression check.
 

Cant Write

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My idle smoke looked blue and it was timing related. Well that and I think too much government idle time.
 

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