Secondary Port Throttle Actuator vacuum leak

[GOLDCYLON]

Originally Posted by Z51JEFF

Daryll,Ill take these if the OP passes.

Jeff I shipped them already. I have another pair but they are not almost new like these were.

[Paul Workman]

Originally Posted by XfireZ51

I got an idea! Pull the throttle plates on the secondaries and we'll throw in a chip that has secondary injectors turn on at anything above idle. You can unplug the secondary MAP sensor and air pump.

Yep! Parts not used seldom fail, and they don't cost anything to replace!

OP: Like most of us that have pulled the secondaries, they haven't given me a lick of trouble since. AND, I like the crisp throttle response, and the clean intake valves!

P.

[boostedmaxPSI]

Took apart the Secondary Actuator to see if my suspicion was correct and it was. The internal spring was not centered causing some binding. the point where the smaller end of the spring that meets the center point of the base was not opened up enought to fully seat around the base point.

I opened the spring up just a bit to see what would happen and the spring stays where it should be, centered.

I'm going to attempt to put this one back together to see if the condition improves. I have nothing to loose given two are on the way.

Base of the spring too small (before modifing the spring)




Spring not centered. This is how the spring was situated when I pulled actuator apart.




This is with the spring opened up a bit more so it could fully seat around the base and stay centered.

[scottfab]

Frank I applaud your decision to stay with the stock setup.
Long term value could well be in how close you stay stock.
(or returnable to stock)
Remembering back I think it was Mark H. that found a lot
of actuators coming from the GM dealership that were defective
in the same way you're seeing.

About 10yrs ago I developed a replacement idea using electrically operated solenoids. I have them still and the brackets for mounting. All that remained was working out where to tie into the electronics which will be trivial once the need arises.
And there in lies the catch. My secondaries have not failed since I worked on them in 99. Once they do begin to act up again I intend to swap out the actuators. This will be reversible and will not require a chip mod which in itself is a potential maintenance issue. (replacement parts)

Good luck with the new parts.

[GOLDCYLON]

Originally Posted by boostedmaxPSI

Took apart the Secondary Actuator to see if my suspicion was correct and it was. The internal spring was not centered causing some binding. the point where the smaller end of the spring that meets the center point of the base was not opened up enought to fully seat around the base point.

I opened the spring up just a bit to see what would happen and the spring stays where it should be, centered.

I'm going to attempt to put this one back together to see if the condition improves. I have nothing to loose given two are on the way.

Base of the spring too small (before modifing the spring)




Spring not centered. This is how the spring was situated when I pulled actuator apart.




This is with the spring opened up a bit more so it could fully seat around the base and stay centered.

Never seen one of these apart before. Cool pics.

[boostedmaxPSI]

UPDATE:

So with nothing to loose, I was able to correct the spring location by widening the spring base a bit and track down a very small pin hole leak. Sealed the leak and put it back together.

IT WORKS. check the video out. The actuator will now hold vacuum with as little as one pump on the vacuum gun.

http://www.youtube.com/watch?v=MlkNWBNtaYo


Question:

What is the correct orientation for the actuator arm. Notice the slight angle. Does the angle point to the center of the engine or to the IH?

[scottfab]

I looked at my photo archives and can't find what I'm looking for.
However this was the source of a lot of exchanges on the ZR1Net mail list
years ago. There were many actuators that were mounted upside down.
Thing is without the pics I can't tell which way it should be.

[boostedmaxPSI]

Originally Posted by scottfab

I looked at my photo archives and can't find what I'm looking for.
However this was the source of a lot of exchanges on the ZR1Net mail list
years ago. There were many actuators that were mounted upside down.
Thing is without the pics I can't tell which way it should be.

Thanks for looking Scott. The actuator arm with the slight angle, is mounted with the angle towards the IH.

Frank