Okay I just got back from testing, at idle I have 11"


Idle - 11"

1/4 Throttle - 2"

1/2 Throttle - ZERO

Full Throttle - Further down ZERO

Now THAT sounds better. You should adjust the VCV per the FSM. In short, this is how it works (with the engine OFF, btw):

1) Loosen both 10mm bolts just enough so you can rotate the VCV
2) Have a friend push the accelerator pedal to the floor and hold it there **
3) Turn the VCV all the way to the left (CCW)
4) Gently turn the VCV back to the right (CW) until resistance is felt
5) Tighten the 2 bolts
6) Tell your friend to let off the pedal.

This almost always results in the VCV being set right smack in the middle of the adjustment range, for the slotted holes in the housing. Don't try to fine-tune the shifting by moving it one way or the other, the VCV is very picky about being set in that one position. I don't quite understand why, and I gave up trying. ;) The shifting can be odd if the VCV isn't set properly.

**Side note: Make sure that with the pedal to the floor, the IP is reaching the full-load stop - this is hard to see, since it's on the back side of the IP, under the intake manifold. A flashlight helps. If it's not reaching the stop, the 3 throttle linkage rods may need adjustment... that is a more complicated, and annoying, procedure. Hopefully you won't need to mess with those.

:stuart:

Sorry I haven't responded yet, its my gf's b-day weekend and I have been pretty busy suprising her =)

I will let you know how the VCV adjustment goes that you gratefully described in intimate detail!

I want to apologize for not completing this thread, it is actually very unlike me I do follow through with things more people wouldn't. I replaced my VCV and was so utterly enthralled that it fixed my issue, it must have put me in a wonderland state where I forgot to come back and let everybody know.

After replacing the VCV I was getting the proper readings from my MittyVac and my shifts were a million times cleaner and smooth.

Thanks everyone for your patience, Bio300TDTdriver for reminding me and most of all peachparts for allowing this kind of collaboration to happen.

Hello all, sorry to bring up an old thread but I am trying to root cause some issues on my car and found this thread had some good information.

I found this reply from gsxr:

"OK... Y29 is the "shift softener" soleniod. When the engine is cold, and Y29 is energized, it's supposed to send modulated vacuum (0-15") from the VCV to both the "VCV" port and the "PRE" port on the BFS (#123).

When the engine is warm, Y29 is not energized; then the "PRE" port is supposed to receive boost pressure from the ALDA branch fitting. The VCV port still receives modulated vacuum from the VCV. The idea is to only allow a full-hard shift when there is X-amount of boost present."

Since my car works exactly the opposite shifts better when cold and harsher when it warms up I wanted to understand how it works. What is the "PRE" port referenced above?

"PRE" is the pressure port for the BFS (or to use the dealer techie term, FPP).

It may not have been covered in this (old!) thread, but I've now completely removed the BFS and all the plumbing, and routed the VCV vacuum signal directly to the transmission. Some minor adjustment was needed at the vacuum modulator, but overall it's working quite well, with a bunch less spaghetti under the hood.

:zorro: