Secondary Vacumm Pump question???

[Roadster]

I have noticed that the Secondary vacumm pump under the right headlight assembly has been disconnected. Therefore the pump was never running. When I plugged it back in, the piump runs continuously. So with that thought in mind:
1-why and would the seconandaries operate?
2- is it safe to assume that the pump needs replacement, or am I missing something here in the way the system functions ?

Again, the engine runs great, and that first complete WOT was nothing short of amazing. And I would also assume that the secondaries are operational, as there is no reason to believe that they were ever disconnected, unless that was performed when GM Engineering owned the Vette for the first 2 years.
From my research on previous owners, it seems that not too many parts were replaced. And the latest fuel filter and spark plugs were changed within the last two thousand miles.

PS....I don't have any stumble or hesitation what-so-ever, when you press down on the accelerator, it is an instant response throughout the gears.

Still learning about everything, so any thoughts or info is appreciated.
Thanks...........................

[Dynomite]

Secondary Functional Test and Reconditioning the Secondary Actuators TIPS

Sounds like you have your secondary system removed. Someone then just disconnected the pump. Look down between the runners of the Plenum as shown in in the link and you should be able to see the secondary actuator arms (one each side). Also...do you see a vacuum line leading from the vacuum pump up and under the Plenum on the passenger front of the engine?

It seems to me that you would loose vacuum at Wide Open Throttle as Plenum Vacuum would drop and the secondaries would then close if they existed given the vacuum pump is disconnected. If you have the secondaries intact, and a complete vacuum system, you definitely have a BIG vacuum leak under the Plenum. The Secondary Functional Test would FAIL under the conditions you have unless the vacuum pump is JUST able to maintain Secondary Vacuum by running constantly.

Is the Vacuum Connection between the two runners on the Drivers Side of the Plenum blocked? If so...that would also indicate the Secondaries have been removed.

If you have a BIG leak in the Vacuum system you are out of luck under ALL conditions operating the secondaries. There is a vacuum check valve under the Plenum which holds vacuum provided by the pump when plenum vacuum is low...that check valve does not function the other way...holding vacuum when the vacuum pump is non functional.

Vacuum provided by the Drivers Side of the Plenum will allow the Secondaries to function under some conditions but once Plenum Vacuum drops you are out of luck with the Secondary Operation.....I am thinking.

[Roadster]

Cliff, thank you for your link, will try to get that done by the end of the day.

[efnfast]

Does the engine rev to 7K?

[Roadster]

Originally Posted by efnfast

Does the engine rev to 7K?

Yes it sure does, and mighty quickly at that. It seems like it wants to climb the rpm range forever.......

And again, no stumbles or anything like that and when you pull a shift, it just climbs where it left off......

I am very satisfied with the way that it runs, that WOT really made my eyeballs bigger......it was like I never imagined the full power this motor has....

[efnfast]

I'm no expert here, but I don't think the secondaries will open at all without the vacuum pump. And if it's revving to 7K, we can assume the secondaries aren't there?

[Kevin]

Originally Posted by efnfast

I'm no expert here, but I don't think the secondaries will open at all without the vacuum pump. And if it's revving to 7K, we can assume the secondaries aren't there?

sounds like a logical assumption. If you're running fine without them don't put them back in

[Roadster]

Originally Posted by efnfast

I'm no expert here, but I don't think the secondaries will open at all without the vacuum pump. And if it's revving to 7K, we can assume the secondaries aren't there?

Originally Posted by Kevin

sounds like a logical assumption. If you're running fine without them don't put them back in

It all makes sense, I am going out to the garage right now and check out some of the items Cliff pointed out in his post.
I guess I woiuld be totally surprised if they are removed......

Ok, I know alot of owners have removed the secondaries, does the engine run that much better with them eliminated? Just curious on that!!!

[Roadster]

Originally Posted by Dynomite

Secondary Functional Test and Reconditioning the Secondary Actuators TIPS

Sounds like you have your secondary system removed. Someone then just disconnected the pump. Look down between the runners of the Plenum as shown in in the link and you should be able to see the secondary actuator arms (one each side). Also...do you see a vacuum line leading from the vacuum pump up and under the Plenum on the passenger front of the engine?

Is the Vacuum Connection between the two runners on the Drivers Side of the Plenum blocked? If so...that would also indicate the Secondaries have been removed. [/B]

Ok after further investigation, I am now assuming that the secondaries are non-exsistent.....
1-pump was and has been disconnected. and from what I am trying to understand, is that with the pump being disconnected, there would be no way that the secondaries would be functional at all, is that a correct assumption???
2-looking down between the runners on each side, I do not see the secondary actuator arms at all. it just looks like an open space on each side.
3-the vacuum line is still connected from the pump and goes under the plenum on the passenger front of the engine, but it feels looser than it should under the plenum.
4-that vacuum connection between the two runners on both sides of the motor are still connected.
5-so I imagine that the secondaries could be eliminated, but everything was not removed in the process.....

[KILLSHOTS]

Originally Posted by Roadster

Ok after further investigation, I am now assuming that the secondaries are non-exsistent.....
1-pump was and has been disconnected. and from what I am trying to understand, is that with the pump being disconnected, there would be no way that the secondaries would be functional at all, is that a correct assumption???
2-looking down between the runners on each side, I do not see the secondary actuator arms at all. it just looks like an open space on each side.
3-the vacuum line is still connected from the pump and goes under the plenum on the passenger front of the engine, but it feels looser than it should under the plenum.
4-that vacuum connection between the two runners on both sides of the motor are still connected.
5-so I imagine that the secondaries could be eliminated, but everything was not removed in the process.....

If you can redline the car with the pump disconnected, then your secondaries are removed. If they were intact, you'd have a hard time revving past 5000. Just turned off my key and confirmed that about an hour ago.