acceleration Judder?

[goose737700]

Hello Everyone:
I am in the final stages of a 1995 EVC Tdi conversion and have a question for all those who have gone before. I have a ahu engine with dsla 1019 injectors, Vnt 15 Turbo and EWB o2b transmission. The ecu is a chipped jb 68 pin unit and I am running a custom tune, which i suspect is the culprit with the engine vibration. I'm trying to gather info so I know where to be looking within the maps. There seems to be some discussion of PID mapping but very little explanation of resolutions in the forums.
Basically at Rpm's between 2000-3000 ~ and vehicle speed Above 40 mph the engine begins to vibrate, shudder, judder whatever you want to call it when any thing over the slightest bit of accelerator is applied. the turbo doesn't go into limp mode and otherwise the van drives fine, egt tracks vehicle speed pretty well. once the Rpm speed increases to 2900~ the engine smooths out and all is well. Anyone's' with personal experience of this phenomena input would be appreciated.

 

[archemitis]

I would say it sounds alot like the ALH in my 74 Transporter. I had very hard urethane motor mounts in it. I had a stage 3 tune and some other stuff. I assumed it was the tune. I switched to rubber mounts and it seemed like a different car. I know the Eurovan is a completely different setup, but in my experience, engine mounting does weird stuff with torque.

What happens if you drive it like you stole it?

 

[goose737700]

more the same, until i break the 2900 rpm barrier the vibration is present and slightly more pronounced. I'm leaning toward the inner CV's being bad, at the moment.

 

[goose737700]

I replaced the passenger side axle and now the vibration is almost completely gone.