My vacuum amplifier output does not go all the way to zero at WOT. I have checked out everything going into the vacuum amplifier and it all seems to be working correctly. Is the amplifier adjustable to reduce the final output to zero? I am currently going down to around 2 in. of vacuum.
TIA
Lee

Connect a boost gauge to the line from the ALDA to the amplifier. Drive the vehicle in third or fourth gear at maximum power and observe the boost gauge. The gauge must read 11 psi. If the boost is not quite up to 11 psi, the amplifier will not get down to 1.2 psi (nominal reading).

The spec for the amplifer is .8-1.6" vacuum at a boost pressure of 11 psi.

I don't believe the output from the amplifier will ever get to zero.

I checked the boost pressure and am getting good boost. The transmission is not shifting properly. It is flairing at the 2-3 and 3-4 shifts under anything less that full throttle. Most of the transmission trouble shooting threads indicates that zero vacuum is needed to have good shifting. I will also offer that I had recently attached the trans vacuum line (from the amplifier) to the trans modulator while doing some maintenance (the rubber vacuum line had broken). Since I have only had the car for a short while, it might have been off all along. Anyway, before I had attached it, it seemed to shift well.
Thanks for the info.
Lee

Zero vacuum is not needed to have good shifting. In fact, the only time that you approach zero is at maximum boost. My personal opinion is that 2 inches of vacuum will do, effectively, the same thing as zero vacuum, if you can ever get there.

You can, of course, prove this to yourself. Just disconnect the line to the transmission and you will have zero vacuum. The shifts should all be very hard, to the point of banging the drive train. If they are not, then, you have other problems.

When the SDL had vacuum leaks, this is exactly what it did. The vacuum to the transmission was much lower than spec.

Brian,
Thanks for the suggestion. It was actually shifting pretty well when the line was not hooked up. Several things that I noticed when I started trouble shooting the trans shifting. When checking the throttle linkage adjustment, I found that all the plastic sockets were cracked. I replaced them and did the adjustments per the manual. When chceking the travel to WOT, I found that the way the linkage was originally adjusted, the IP lever would not travel close to the stop. When I adjusted the linkage so that the IP lever would go to the stop, then it did not return all the way to neutral. That left the idle around 1000 rpm. I adjusted the idle down to around 550 rpm using the adjustment screw on the IP. However, it seems to run a lot rougher when cold than before. I am wondering if the pivot bracket that links the accelerator linkage to the IP is slightly bent, thus causing the limited travel.

Does anyone have experience with this bracket bending?

Last note is that I get around 11-12 second 0 - 60 mph times (have not been very precise with the test). So I think that most everything is working ok, I am just fustrated with the shifting.

Thanks

I cannot help you with the bracket being bent.

However, if the trans is shifting pretty well, meaning it's not very hard in it's shifts, with zero vacuum, then something is amiss within the trans.

Any additional vacuum added above this level will cause softer shifts, to the point of flaring. This is apparently what is occuring with yours.

proper shifting of your tranny is reliant upon a balance of two factors.one being vacuum modulation via the module you mention and the other being mechanical modulation in conjunction with the accelerator linkage.both of these must be adjusted correctly to work in unison.try a search of previous threads.i beleive Steve Brotherton explained this concept in detail