Maybe the new IP is bad. YOur description of running it up the the governor fairly smoothly then backing it off and it runs rough sounds like a fuel pump issue.
Wish I had a good answer for you. THis kind of problem kills the fun.

 

I just did an autoto getrag swap and had the same problem. The solution was a combination of two things.

First, the machine shop bored the hole for the pilot shaft bearing off-center, causing a nasty thud-thud. Trans came back out, had it re-bored and thud was gone but the truck still shook at an idle.

It ended up being the new trans mounts I put in. I had them too tight and they were transmitting engine vibration to the cab. The truck was so shaky you could not see out of any of the mirrors at an idle. I backed off on the trans mounts some, and she is well, as smooth as any 1st gen diesel...

Your writeup was a great help in my swap. Thanks for sharing.

 

Interesting. Mine are as tight as they get. Maybe at lunchtime I'll try to loosen them up a tad and make sure they're seated right.

Glad my swap helped...it was a worthwhile endevour, I think.

 

I think your dynamic advance is sticking full on in the pump. Try retarding the timing and see if it smooths out.

 

I just backed mine off two turns from tight and left them. I did use nylocks, so I could be sure not to lose a nut.

good luck

 

Could you expand on that a little bit? Would this have to do with the KSB or a totally different issue. I kind of have a feeling it's fuel system related, but I just don't know where to go from there.

 

There is a piston in the pump that advances the effective pump timing as the rpm of the pump changed (using fuel pressure). If the piston sticks in the advanced position it will make your truck shake if your pump timing is advanced.

 

Interesting. I suppose that could indeed be it. My timing is advanced a little bit, although not much.

I wonder how one would diagnose and unstick the piston.

 

5lb sledge

 

Ha! Lightly tap the side of the pump with the sledge?

 

I still have a vibrationin mine. Here is what all I did. I had the trans out 3 times (two different trans) . Had the valves readjusted, (needed it done bad). Now that another member posted about the trans mount....as I had put new ones in....and I TIGHTENED them up......hmmmmm.

Did you ever pull your driveshaft apart, or maybe U -joints. THAT is one thing that helped mine, took away a good part of driveline vibration, and I also replaced the front shaft......although even with it removed, made no difference.

To me and mine....it almost seems like its slightly missing while driving....is that the same as yours (although it deems to run fine) ?

 

That is EXACTLY how it feels to me.

So, I came how at lunch today and decided to tear into the trans mount. I jacked up the TC a bit and took out the mount bolts. Then I cleaned everything up real nice and noticed that the holes weren't lining up with the crossmember, and remembered I had to use a pry bar to get it aligned right.

So, I pulled the upper part of the mount out and elongated the holes a little bit so everything would line up, and then made sure the rubber was in right and the inside collar was where it should be and bolted it all back together.

This seemed to help a bit, actually, with the transmission of the vibration, but the engine still vibrates more than I feel it should...which is aggravating.

It's interesting to me that you have the same issue...tell me more...maybe we can figure out each other's problems.

Got it back together, but had to call out of work for the rest of the day as it took longer than I expected it to.

 

Although I havent had tome to go look. I am wondering if the trans mounts are too tight. I put new trans mounts in, have had them out three times now, making sure when I reinstall they are in the right position.....

Would it be possible to loosen them up bout 3-5 turns on the nut, and drive it to see if it "re-aligns" itself? Another member posted about re-aligning the driveline, but I have never heard of anyone doing that nor do I know how to do it.

Anyone do this?

 

Well, I drove around for 45 minutes or so this afternoon, running errands. Fixing my back mount (coupled with doing the motor mounts last week) seemed to help. I can still feel the engine vibrate, and it does have a weird...miss type of sound to it while I'm driving, but it sure is a lot better. I guess the test will be driving it tomorrow morning for a little while.

 

Another weekend past and the transmission mount adjustments DEFINITELY helped a lot. The engine still shakes more than I think it should, but it's definitely not on the auction block anymore.