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Old 08-05-2015, 03:04 PM
Junkman Junkman is offline
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Join Date: Sep 2006
Location: Middle TN
Posts: 3,530
Originally Posted by Zacharias View Post
I don't think you should be able to get the VCV to drop vacuum to zero by just moving the linkage while the car is running, stationary. It should only drop the vac to zero when the transmission should be shifting. Linkage movement with the car sitting still doesn't mimic driving conditions.
The FSM calls for the VCV linkage to be disconnected for the test. There is a 10mm gauge that measures where the vac is supposed to drop. I made a gauge by drilling a 1/8 hole approximately in the middle of a nickle. Disconnect the linkage, open the VCV 10mm based on your fancy custom gauge which approximates what the pedal would do without reving the engine and adjust the VCV. Leave the cap off the VCV, hook up the linkage and go drive. Harsh shifts and you need to increase vacuum (or plug some leaks which cause low vacuum). Soft shifts and you decrease vacuum.

The modulator pressure needs to be correct and vacuum leaks need to be under control or at least consistent before you mess with the VCV.
85SD 240K & stopped counting. 84SD 180,000. Thinking of painting both.
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