vibrating engine

[snowman89]

I have a 1987 f-250 with a 1988 7.3 with a zf 5spd. When I fire it up hot or cold it shakes A LOT. When I go down the road, the sticks to my tranny shake too. I replaced the motor mounts and tranny mount and it still does it. I even did an injector/cylinder test and they apparantly all work. I even put injector cleaner in it and still shakin. Please help

 

[97idi]

well one a diesel aint no gas engine lol they are rough and loud because of the huge pressure spike when the fuel lights (thats why the new trucks have things like pilot injection) also u could have air getting into the fuel system somewhare, iam not shure if timing could create alot of shaking but u never know. iam shure others will give some more ideas but thats what i have at the moment good luck

 

[97idi]

well mine runs like a diesel at idle after that its like a gasser, but also when iam on bio or a heavy dose of atf with the diesel it idles just as smooth as a gasser

 

[87crewdually]

Possibly the dual mass fly wheel is failing or broke.

 

[starmilt]

Check your fan clutch.

 

[6 Nebraska IDIs]

The problem with a vibrating issue is that it could be so many different things, you're just going to have to take everything everyone tells you and start eliminating the variables.
In the case of my moms CC with a POS 6.9 we purchased as a rebuilt engine, it feels like you're breaking warp speed or something when you get over 2300rpm I've wrapped it out to 3500rpm just to see if it would come apart and it doesnt. I think its a combination of an unbalanced rotating assembly and the apparent lack of a thrust bearing in the mains.
As mentioned above the dual mass flywheel will make it vibrate if its gone bad, but if it has gone bad there's a reason for it, which could be another vibrating issue, when injectors get worn they dont wear evenly, and they pop at different pressures. This poping at random pressures makes the motor unbalanced in its own sense, because of the cylinders having slightly different firing times. This problem even happens with some NEW injectors, thats why its important to have a set of injectors pressure matched.

 

[snowman89]

Its not the flywheel cause i converted it to a single mass when i did the clutch

 

[snowman89]

k guys a little better description is

at 1000 rpm it kind of shudders. after 1300 rpm it smooths out

 

[damac]

We are new to diesels and got this old 85 a few months ago. The only time I have ever noticed the engine stumble to the point of feeling it was the air introduction into the fuel.

Both our back tanks have issues below 1/4 tank.

We have a manual push button for the glowplugs, hit those for 10 seconds, fire it up and even then while cold the engine seems pretty smooth with the high idle on. Just for fun I hit the glowplugs once in a while during warmup while I am in the cab, like the old controller would do.

I was actually surprised the engine was so smooth and it is that way and revs up and down smooth across the board.

Don't have any history with diesels but it just made me wonder, what would happen if you had the smallest air introduction and it was constantly effecting one of these trucks.

We also pulled the water seperator off.