Clicking from this… what is it?

[G-Sting]

When the key is turned to electrics on, but prior to start, this clicks quite audibly ever 1.5 seconds. What is it, and is it supposed to make that sound? It's located under the hood up towards the right front facia of the '94 Z.

(BTW, Z manuals are on order!)

http://i1317.photobucket.com/albums/t629/gmanontheroad/Vette/IMG_8131_zpsylewdte0.jpg

[XfireZ51]

Secondary vacuum pump. If its turning on every few seconds, you have a vacuum leak somewhere in the system.

[We Gone]

Sounds like it is trying to cycle on once on it should run at least a few seconds. It is the vacuum pump for the secondary's. It may be repairable. Check out Dynomite's sticky's or I'm sure he will post up a link.

[Dynomite]

Sounds like it is trying to cycle on once on it should run at least a few seconds. It is the vacuum pump for the secondary's. It may be repairable. Check out Dynomite's sticky's or I'm sure he will post up a link.

:D

VACUUM SYSTEM
Vacuum Systems 90' and 91' (Secondary and Cruize/HVAC) TIPS (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-2.html#post1581460752)
Checking for Vacuum Leaks TIPS (http://www.zr1.net/forum/showthread.php?p=187897)
Failed Vacuum Check Valve TIPS (http://www.zr1.net/forum/showthread.php?p=221908)
Finding Vacuum Leak TIPS (http://www.zr1.net/forum/showthread.php?p=221893)
Condition of Secondary Vacuum System TIPS (http://forums.corvetteforum.com/c4-zr-1-discussion/3340987-continued-miss-stumble.html#post1584980706)
Vacuum Pump Taken Apart TIPS (http://www.zr1.net/forum/showthread.php?p=188137)
Differential Pressure Switch Function TIPS (http://www.zr1.net/forum/showthread.php?p=87049)
Secondary Vacuum Removal TIPS ([URL]http://www.zr1.net/forum/showthread.php?t=19842)
HVAC, Brake Booster, and Purge Vacuum Leaks TIPS ([URL]http://www.zr1.net/forum/showthread.php?p=137443)
Secondary Vacuum Reservoir Source TIPS ([URL]http://www.zr1.net/forum/showthread.php?t=16711)
Vacuum testing ([URL]http://www.secondchancegarage.com/public/186.cfm)
Secondary port vacuum diagnosis ([URL]http://www.corvetteactioncenter.com/tech/howto/idx.php/0/002/article/)
Secondary diagnosis ([URL]http://www.corvetteactioncenter.com/forums/c4-corvette-zr-1/14272-1990-1995-zr-1-secondary-port-vacuum-diagnosis.html)
Vacuum solenoid ([URL]http://www.zr1.net/forum/showthread.php?p=107600)
Trouble Shooting Secondary Vacuum System (http://forums.corvetteforum.com/c4-zr-1-discussion/3151128-90z-secondary-help-needed.html#post1582131111)
Cruise Control Vacuum ([URL]http://www.zr1.net/forum/showthread.php?p=64690#post64690)
Cruise Control Inoperable Diagnostics (http://www.zr1.net/forum/showthread.php?p=181739)
Secondary vacuum diagram ([URL]http://www.zr1.net/forum/showthread.php?p=77640)
Vacuum pump malfunction ([URL]http://www.zr1.net/forum/showthread.php?p=74766)
Non operating secondaries ([URL]http://www.zr1.net/forum/showthread.php?t=9087)
Vacuum pump vendor ([URL]http://www.zr1.net/forum/showthread.php?p=82942)
Vacuum solenoid conversion ([URL]http://www.zr1.net/forum/showthread.php?p=100540)
Check valve under plenum ([URL]http://www.zr1.net/forum/showthread.php?p=43153)

When the key is turned to electrics on, but prior to start, this clicks quite audibly ever 1.5 seconds.

You have a vacuum leak between the vacuum pump and Under the Plenum.

[G-Sting]

Secondary vacuum pump. If its turning on every few seconds, you have a vacuum leak somewhere in the system.

Got it, thanks all. Will begin to check it out.

The Z starts right up, idles great, runs smooth and like a beast. Appears to be all stock, 19k miles. Wasn't driven but 1,700 miles in the last 9 years.

Narrow it down any?
:icon_scra

[Dynomite]

Got it, thanks all. Will begin to check it out.

The Z starts right up, idles great, runs smooth and like a beast. Appears to be all stock, 19k miles. Wasn't driven but 1,700 miles in the last 9 years.

Narrow it down any?
:icon_scra
Check between Vacuum Pump and Plenum first....then check Drivers side Plenum Vacuum Connection to see if the Check Valve under Plenum is leaking. Disconnect that vacuum fitting and hold finger over end of vacuum line to see if pump stops cycling...if pump stops cycling the Check Valve is leaking.

Checking for Vacuum Leaks TIPS (http://www.zr1.net/forum/showthread.php?p=187897)
Finding Vacuum Leak TIPS (http://www.zr1.net/forum/showthread.php?p=221893)

1. Secondary Vacuum System
The first photo shows details of the vacuum plumbing around the Secondary Vacuum Solenoid and Secondary Vacuum Reservoir Including the Check Valve. The second photo is the complete Secondary Vacuum System.

The Check Valve allows plenum vacuum to be seen by Secondary Vacuum Reservoir but does not allow plenum to see Vacuum pump vacuum.

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite12/Vacuum%20solenoid%20Check.jpg
http://i287.photobucket.com/albums/ll142/dynomite007/LT5/SecondaryVacuumSys-1.jpg

[G-Sting]

Check between Vacuum Pump and Plenum first....then check Drivers side Plenum Vacuum Connection to see if the Check Valve under Plenum is leaking. Disconnect that vacuum fitting and hold finger over end of vacuum line to see if pump stops cycling...if pump stops cycling the check valve is leaking.


Dynomite, that (in bold) did it! Holding finger over the end of the nylon vacuum line resulted in the vacuum pump cycling about every 10 seconds - much less often.

The rubber fitting appeared to be very lose, and I zip-tied it to hold the nylon vacuum line tighter, but no change in the 1.5s cycling of the vacuum pump. Must be the aforementioned leaky check valve?

Great pics, BTW!

[Dynomite]

Dynomite, that (in bold) did it! Holding finger over the end of the nylon vacuum line resulted in the vacuum pump cycling about every 10 seconds - much less often.

The rubber fitting appeared to be very lose, and I zip-tied it to hold the nylon vacuum line tighter, but no change in the 1.5s cycling of the vacuum pump. Must be the aforementioned leaky check valve?

Great pics, BTW!


Vacuum Check Valve (http://www.jerrysgaskets.com/valve-vacuum-in-line-check-90-95-8c2)

Make sure it is installed correct direction :p

Unfortunately you have to remove Plenum to Replace Check Valve.

[G-Sting]

Vacuum Check Valve (http://www.jerrysgaskets.com/valve-vacuum-in-line-check-90-95-8c2)

Make sure it is installed correct direction :p

Unfortunately you have to remove Plenum to Replace Check Valve.

I had been browsing about all those who've pulled the Plenum for various things… and was literally thinking yesterday "glad I don't have to pull the Plenum until way down the road on this low mile Z." lol

Well, in the meantime…

1. Is there any problem with driving it for a bit before I do this?
2. What does that vacuum pump do for the secondaries before start?
3. Trying to keep it stock… for a least a month or two or three… and drive and enjoy it. But, what else should one check or replace when finally pulling the Plenum?

Thanks for the tremendous help!
G

[Kevin]

Got it, thanks all. Will begin to check it out.

The Z starts right up, idles great, runs smooth and like a beast. Appears to be all stock, 19k miles. Wasn't driven but 1,700 miles in the last 9 years.

Narrow it down any?
:icon_scra

just replace every part you can.

[Dynomite]

I had been browsing about all those who've pulled the Plenum for various things… and was literally thinking yesterday "glad I don't have to pull the Plenum until way down the road on this low mile Z." lol

Well, in the meantime…

1. Is there any problem with driving it for a bit before I do this?
2. What does that vacuum pump do for the secondaries before start?
3. Trying to keep it stock… for a least a month or two or three… and drive and enjoy it. But, what else should one check or replace when finally pulling the Plenum?

Thanks for the tremendous help!
G

Naw ......just run it.......your Plenum vacuum will take over for most instances. The Vacuum Pump just takes over when Plenum Vacuum drops such that the secondaries cannot be pulled open.

Removing Plenum (including the 10 minute Plenum Removal) (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-4.html#post1581663365)

Check/replace injectors, Check Vacuum System, Recondition Starter, Clean Valley/Valley Drain.....and so on ;)

Minimum Restoration of a 1990 ZR-1 (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-7.html#post1585219749)

It is ALL in signature :D

I am a big promoter of TB Coolant Elimination at Injector Housing so you can do the 10 minute Plenum Removal.
I Eliminate TB Coolant without it being noticed by looking at the engine......looks like TB Coolant is there but it is not :sign10:

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite10/63a572bd-1dd6-4143-b2f1-1b01bafe478a.jpg

[Kevin]

Naw ......just run it.......your Plenum vacuum will take over for most instances. The Vacuum Pump just takes over when Plenum Vacuum drops such that the secondaries cannot be pulled open.



unless you want to drive the car on the highway in 5th or 6th gear.

[SteveCanyon]

My vacuum pump starts/stops with 5-6 sec intervals between running (runs for maybe .5 sec each time). Not sure if it has a leak somewhere but have no drive ability issues.

[G-Sting]

Naw ......just run it.......your Plenum vacuum will take over for most instances. The Vacuum Pump just takes over when Plenum Vacuum drops such that the secondaries cannot be pulled open.

Removing Plenum (including the 10 minute Plenum Removal) (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-4.html#post1581663365)

Check/replace injectors, Check Vacuum System, Recondition Starter, Clean Valley/Valley Drain.....and so on ;)

Minimum Restoration of a 1990 ZR-1 (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-7.html#post1585219749)

It is ALL in signature :D

I am a big promoter of TB Coolant Elimination at Injector Housing so you can do the 10 minute Plenum Removal.
I Eliminate TB Coolant without it being noticed by looking at the engine......looks like TB Coolant is there but it is not :sign10:

Great stuff, Dynomite. Much appreciated. Not gonna do anything too soon, as long as it runs well… but will accumulate the appropriate replacement parts, and read up.

Kevin - Thanks for your comments as well.

:cheers:
G

[Dynomite]

My vacuum pump starts/stops with 5-6 sec intervals between running (runs for maybe .5 sec each time). Not sure if it has a leak somewhere but have no drive ability issues.

Steve.....you have a vacuum leak which as you describe will not be significant in terms of the Secondaries operational until the vacuum pump is running continuously. That indicates the vacuum pump cannot keep up with the leak (if the Vacuum Pump runs continuously with switch on and engine not running).

I think almost everyone has a vacuum leak of sorts unless the vacuum pump runs for a couple seconds and stays off for a minute or more. That is an indication of a significant tight Vacuum System if the Vacuum Pump stays off for a minute or more (with switch on and engine not running).

[SteveCanyon]

I tracked down my leak to the tube coming out of the pump, the first connection before going under the plenum where it comes apart was the source. When I held the connection tight that fixed it. I put a little clear silicone to secure it and problem fixed. Glad that was it since I just pulled the plenum last week to do the injectors and did not want to do that again for a while!

[Dynomite]

I tracked down my leak to the tube coming out of the pump, the first connection before going under the plenum where it comes apart was the source. When I held the connection tight that fixed it. I put a little clear silicone to secure it and problem fixed. Glad that was it since I just pulled the plenum last week to do the injectors and did not want to do that again for a while!

Good for you :thumbsup: and thanks for following up on the issue and your fix :handshak:

[G-Sting]

I tracked down my leak to the tube coming out of the pump, the first connection before going under the plenum where it comes apart was the source. When I held the connection tight that fixed it. I put a little clear silicone to secure it and problem fixed. Glad that was it since I just pulled the plenum last week to do the injectors and did not want to do that again for a while!

Glad to hear you were able to repair it with a simple fix, Steve.

My problem appeared to be in the same area. A tie-wrap around the rubber fitting where the nylon vacuum line goes in, and driving around a bit, seems to have cured it. Now, prior to start, the pump runs for about 3 seconds, shuts off and is quiet.

Curious.. Does the vacuum pump require occasional lubrication or overhaul?

:cheers:

[Dynomite]

Glad to hear you were able to repair it with a simple fix, Steve.

My problem appeared to be in the same area. A tie-wrap around the rubber fitting where the nylon vacuum line goes in, and driving around a bit, seems to have cured it. Now, prior to start, the pump runs for about 3 seconds, shuts off and is quiet.

Curious.. Does the vacuum pump require occasional lubrication or overhaul?

:cheers:

Vacuum Pump Taken Apart TIPS (http://www.zr1.net/forum/showthread.php?p=188137)

I recall someone here on the forum taking apart a vacuum pump but that is rare. I do not recall any lubrication required :cheers:

[G-Sting]

Vacuum Pump Taken Apart TIPS (http://www.zr1.net/forum/showthread.php?p=188137)

I recall someone here on the forum taking apart a vacuum pump but that is rare. I do not recall any lubrication required :cheers:

Got it. Grazie!

:thumbsup: