5.9 magnum engine swap issues

[RyanVandewater]

I have a 1998 Ram 2500 4x4 with the 5.9 magnum, i traded it for one of my project jeeps and the truck only has 86,000 miles and the body is solid, but driving it home after trading it decided to eat a couple exhaust valves and a piston, so i decided to do a motor swap, ive done countless engine swaps with no issues, i labeled my wiring harness, and labeled and separated all nuts and bolts. everything was going well until i went and picked up the only used 5.9 i could find within 500 miles this motor was out of a 1994 and had alot more vacuum hook ups and a big fat ugly egr on the intake.... my 98 did not have egr, so i figured if it isnt hooked up ill just leave it there and it shouldnt affect anything??? and as far as the extra vacuum line hook up on each side of the intake i just put a rubber nipple over them, swapped all of my sensors and distributor over, because the 94 had all different pigtails on EVERYTHING! and i hooked everything up then i made another huge discovery, the flex plate on my 98 had weights on it (for balancing?) and the one on the 94 did not, and the bolt pattern on the one for the 94 did not line up with my torque converter, so i put my original flex plate on the 94 and everything went together perfect, almost to perfect. now heres my issues, truck starts right up and idles at 700 rpms it does idle rough so rough to the point where if i step on the brake and go to put it in gear it stalls out, i started messing with vacuum lines and noticed if in pulled the vacuum line going from the intake to the master cylinder/brake booster the truck revs up to 1400 rpms and runs perfect and i can put it in gear no issues , so do i have a serious vacuum issue somewhere? or is my torque converter going out on me? and is it worth it to swap the intake on my 98 to this 94 engine and do an egr delete? could this be my serious vacuum issue? any help would be greatly appreciated!

 

[MoparMagic'00]

Id say yes swap intakes solves a few issues one pbeing the intake flow and egr problem. Secondly there were different style balancing practices early in magnum engines i just wasnt sure if they carried into the 2nd gen trucks.. I cant remember what was all different just know some weights were on converter others on the flywheel/flex plate (called flywheel by some due to the ring for crank shaft position sensor) ill try and see if i can find my mopar performance book and try to clarify issues for balancing.. Keep in mind that may be a mute point since you stayed with the newer plate and converter if i read correctly.. (New to tapatalk since pc failed) maybe someone else can help further.

 

[RyanVandewater]

Will the 98 intake manifold without egr fit on to the 94 engine???

 

[dapepper9]

Will the 98 intake manifold without egr fit on to the 94 engine???

Yep, it'll swap right over and bolt in but some of the rubbing will be on tiger opposite side iirc. Double check that with Merc225hp or DodgeDude94

 

[rowdyram]

I could be wrong but its my understanding the 5.2 is internally balanced and uses 90° converter pads and 5.9 is externally balanced and uses 1 offset pad. If this is correct you got a 5.2.
As for the egr its fine to leave it. My engine is also out of an older truck with egr. I ran it with the valve on there for a while till I made a block off plate.
The big question is, did you set fuel sync? Sounds like that may be your problem.