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Old 04-22-2012   #1
boostedmaxPSI
 
Join Date: Apr 2012
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Default Secondary Port Throttle Actuator vacuum leak

Guys,

Something had been gnawing on me about the condition of the secondaries and how well they were working. I had addressed the vacuum leaks but I always felt something was fully opening/working.

So.... off comes the plenum again, for additional testing for peace of mind.

This time I hooked up a vacuum gage inline so I could see how much vacuum was being lost when I backprobed pin C17 to activate the secondaries.

First thing I noticed was the driver side secondary ports were fully open and the passenger side ports were only opening part way. In addition to the passenger ports not opening all the way, my vacuum gauge would drop below 5" and the driver side actuator would start to close partly.

I isolated the problem to the passenger actuator itself. Please see the attached video:

http://www.youtube.com/watch?v=yjtZA...ature=youtu.be

Notice how the vacuum starts to bleed off almost instantly. This does not happen to the driver side actuator however, the passenger side actuator will hold vacuum when you go above 15" vacuum. I assume this is because the internal diaphragm is laying over itself and sealing the internal leak.

Another observation is how the diaphragm pulls in at an odd angle. Seems like something is not centered internally to the actuator.

Thoughts?

I plan on purchasing two new GM units tomorrow. Who do you recommend that I source these parts from?

thanks
Frank
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Old 04-22-2012   #2
Z51JEFF
 
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Default Re: Secondary Port Throttle Actuator vacuum leak

Quote:
Originally Posted by boostedmaxPSI View Post
Guys,

Something had been gnawing on me about the condition of the secondaries and how well they were working. I had addressed the vacuum leaks but I always felt something was fully opening/working.

So.... off comes the plenum again, for additional testing for peace of mind.

This time I hooked up a vacuum gage inline so I could see how much vacuum was being lost when I backprobed pin C17 to activate the secondaries.

First thing I noticed was the driver side secondary ports were fully open and the passenger side ports were only opening part way. In addition to the passenger ports not opening all the way, my vacuum gauge would drop below 5" and the driver side actuator would start to close partly.

I isolated the problem to the passenger actuator itself. Please see the attached video:

http://www.youtube.com/watch?v=yjtZA...ature=youtu.be

Notice how the vacuum starts to bleed off almost instantly. This does not happen to the driver side actuator however, the passenger side actuator will hold vacuum when you go above 15" vacuum. I assume this is because the internal diaphragm is laying over itself and sealing the internal leak.

Another observation is how the diaphragm pulls in at an odd angle. Seems like something is not centered internally to the actuator.

Thoughts?
I plan on purchasing two new GM units tomorrow. Who do you recommend that I source these parts from?

thanks
Frank
Id check with Jerrys Gaskets first.
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Old 04-22-2012   #3
GOLDCYLON
 
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Default Re: Secondary Port Throttle Actuator vacuum leak

I have a used pair of vaccum actuators that I no longer need they were purchased from Tom Henry Chevrolet in early 2011. Hows $100 for the pair plus shipping sound? I paid $125 each for these but they are one year used. Lmk. GC
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Last edited by GOLDCYLON; 04-22-2012 at 05:21 PM.
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Old 04-22-2012   #4
GOLDCYLON
 
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Default Re: Secondary Port Throttle Actuator vacuum leak

These pull at an unnatural angle as designed by GM. If they lengthed and centered the rod it would have been a better design. I am sending you a pic of mine attached to the actuator rod when we pulled them out of the car.




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380 P&P&PCed,Ported Heads,Jeal Long tubes,/Fidanza,Corsas/FIKSE FM-5s /LED TLs, HID Projectors, F/R Baer Eradaspeed Rotors with CE/GS RED/BL calipers,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer AVIC Nav system with Voice Command, Ipod, DVD,bluetooth and rear view camera,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC Hidden Display, home Link sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather Banski trailing arms, guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, console Seat cushion, 96CE seats in Black custom Sheepskins, billet catch can,Remote Entry/alarm,Cragar Rear Louvers,LED side louver lights.

Last edited by GOLDCYLON; 04-22-2012 at 05:22 PM.
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Old 04-22-2012   #5
A26B
 
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Default Re: Secondary Port Throttle Actuator vacuum leak

The actuator actually pulls straight with the "angled linkage" installation. If you turn it over & make the linkage "straight", the diaphram will pull at an angle, resulting in binding. FOr best operation, leave the actuator angled, the way it originally & intentionally came from MerCruiser.

Good pictures Daryll.
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Old 04-22-2012   #6
GOLDCYLON
 
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Default Re: Secondary Port Throttle Actuator vacuum leak

Quote:
Originally Posted by A26B View Post
The actuator actually pulls straight with the "angled linkage" installation. If you turn it over & make the linkage "straight", the diaphram will pull at an angle, resulting in binding. FOr best operation, leave the actuator angled, the way it originally & intentionally came from MerCruiser.

Good pictures Daryll.

True statement.
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380 P&P&PCed,Ported Heads,Jeal Long tubes,/Fidanza,Corsas/FIKSE FM-5s /LED TLs, HID Projectors, F/R Baer Eradaspeed Rotors with CE/GS RED/BL calipers,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer AVIC Nav system with Voice Command, Ipod, DVD,bluetooth and rear view camera,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC Hidden Display, home Link sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather Banski trailing arms, guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, console Seat cushion, 96CE seats in Black custom Sheepskins, billet catch can,Remote Entry/alarm,Cragar Rear Louvers,LED side louver lights.
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Old 04-22-2012   #7
boostedmaxPSI
 
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Default Re: Secondary Port Throttle Actuator vacuum leak

Quote:
Originally Posted by GOLDCYLON View Post
I have a used pair of vaccum actuators that I no longer need they were purchased from Tom Henry Chevrolet in early 2011. Hows $100 for the pair plus shipping sound? I paid $125 each for these but they are one year used. Lmk. GC
When you apply vacuum to these units how does the center rod get pulled in? Did you notice in the video that I posted how the rod will make contact to the housing? I assume there is something off internally.
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Old 04-22-2012   #8
GOLDCYLON
 
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Default Re: Secondary Port Throttle Actuator vacuum leak

Quote:
Originally Posted by boostedmaxPSI View Post
When you apply vacuum to these units how does the center rod get pulled in? Did you notice in the video that I posted how the rod will make contact to the housing? I assume there is something off internally.
Correct it should not slap the housing as demonstrated in your video. They will slightly graze the edges somewhat center and hold vaccum. All these are are vaccum diaphrams when they age and wear they leak and set a CODE 61. We have all been there and done that.
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380 P&P&PCed,Ported Heads,Jeal Long tubes,/Fidanza,Corsas/FIKSE FM-5s /LED TLs, HID Projectors, F/R Baer Eradaspeed Rotors with CE/GS RED/BL calipers,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer AVIC Nav system with Voice Command, Ipod, DVD,bluetooth and rear view camera,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC Hidden Display, home Link sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather Banski trailing arms, guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, console Seat cushion, 96CE seats in Black custom Sheepskins, billet catch can,Remote Entry/alarm,Cragar Rear Louvers,LED side louver lights.

Last edited by GOLDCYLON; 04-22-2012 at 07:16 PM.
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Old 04-22-2012   #9
XfireZ51
 
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Default Re: Secondary Port Throttle Actuator vacuum leak

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.
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Old 04-23-2012   #10
Z51JEFF
 
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Default Re: Secondary Port Throttle Actuator vacuum leak

Daryll,Ill take these if the OP passes.
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