94 7.3 Always something noisy

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Mar 13, 2013 | 09:26 AM

fordpickupguy2001

Thread Starter

Freshman User

Joined: Sep 2002

Posts: 49

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From: Sullivan, IN

94 7.3 Always something noisy

I bought a 94 f-250 7.3 IDI turbo a few years back and has been a great truck till last fall. After a routine oil change and about 1500 miles it started having a knock once and a while. Not when cold and not 100% of the time. Sounds like upper drivers side. Sometimes it sounds like upper pass. side. New injectors quieted it down a little. I've tried thinner and thicker oil, no change. Today I started it and ran fine for about 3 min. Then started running real rough, and white/blue smoke out the exhaust. I've narrowed it to one cylinder it's spraying diesel back up through the threads of the injector also bored a hole through the plastic return cap that goes around the bottom of the injector and spewing diesel out of that too now. I've tried different injector and cap and it did it again. I've pulled the valve cover and all rockers are moving about the same distances and push rods are straight. Any ideas?

Mar 13, 2013 | 01:38 PM

Phy

Fleet Mechanic

Joined: Jan 2011

Posts: 1,709

Likes: 4

From: 8600 ft in Colo

Sounds like that injector isn't sealing down in the head, letting cylinder pressure blow back up around the threads, but I don't know for sure.
Try posting in the IDI forum:
Pre-Power Stroke Diesel (7.3L IDI & 6.9L) - Ford Truck Enthusiasts Forums