money pit

[truckermark]

since this seems to be one of those problems no one can identify. even a diesel mechanic iv deiced to start a new thread on what i have done and tried so far.

93 f250 7.3l idi N/A e40d 4x4

well a while back i replaced the injectors and then i realised the pump was bad. so ater i installed my new baby moose pump i noticed a knock at high rpm and under load but not at idel and after i cracked the lines i found the knock stoped when i cracked the number 5 line. so naturaly i bought a new injector and still no cigar. so after a week of fiddling with the timing and such i finaly to it to a diesel shop where they played with it little and found advanceing the timing a little helped it but it was still there. so now i am clueles. does anyone have any idea on what this could be and how to check said idea?

i have noticed that when i lighly tengage the throttel slowly increasing rpms the knock is quiter. but gosseing it it is louder. and on take off just riving it at all cuases the knock

 

[rattleonby]

I wish i could hear the engine. A "knock" is a term loosely thrown around the forum here as our engines are loud and hard to distinguish a definitive knock in these engines....let alone every one of these engines sounds a lil bit different from what my experiences have been with them. If you said the knock goes away when you crack #5 even after replacing the pump and #5 injector then it could be a mechanical issue. Possibly a rod bearing, wrist pin, or even a piston skirt slapping the wall of the cylinder.

But dont write it off as mechanical just yet. Have you ruled out a fuel knock? Fuel quality can play big roles in performance and overall running sound of these engines. As does having the engine properly timed.

 

[truckermark]

well i just toped off eith fresh fuel from almost a quater to above full and nothing canged but we will see. and since its that cylinder alone can it even be a fuel issue. same with timing. wouldent that affect all cylinders?

also through out the driving range the truck begins to shake at 1000 rpm then smothes out by 1500

and how do ytou post a video? sorry mechanicly inclined but put me on a computer

 

[direwulf23]

It is advisable to use a fuel lubricant with this ultra low sulfur fuel nowadays

1994 Ford F250, 2wd, 7.3L IDI, NA, E4OD

 

[FarmerFrank]

Sounds like it COULD be a wrist pin knock. I'd go away because there isn't as much combustion when you crack the line therefore taking the stress off the wrist pin.

My 2wd truck has one hell of a wrist pin knock. Engine has 190k on it, put that engine in the truck, started it and it had that damn loud tick/knocking sound. Been tickin away for 7-8k miles now and ill ride that pony till it stops.

Ill try cracking my lines tonight to see if it goes away in one cylinder because I'm positive that's what my sound is.

 

[Agnem]

What's your oil pressure like? Get that timing spot on and then you will know for sure. Also, just curious, why didn't you just swap 2 injectors between cylinders? That would have avoided the expense of the additional injector, and allowed you to validate the problem stayed with the cylinder. You don't have any injection lines leaking at the pump do you?

 

[truckermark]

thanks for all the replys though guys howeever i found out the problem! it turned out a little grime locking inside the return cap was cuasing thew knock somehow..i fixed it by cleaning it out. dont know how it cuased the knock but after spending so much money i will take this as a win!