Vacuum leaks - Page 2 - ZR-1 Net Registry Forums

cuisinartvette · 09-05-2005

Ok, after coming back from a long drive, I parked it and shut it off. Withthe key in the ON position, I heard from the front pass. side what I'm assuming was the pump ecery 10 seocnds or so. The pump was on for a fraction of a second. Did that twice-Was kind of in a hurry so I didn'y check it with the motor running. I should have a minute or two tomorrow to go play with it some more.

Also, is it common for the doorlock mechanisms to get sticky? Keyless wasn't opening them. You can hear it, but they don't go. Got inside, flipped the lock switch back and forth a 1/2 dozen times and they freed up. Went to lock it with keyless, same thing. Is this an easy fix or am I buying something?

Gotta say, this thing is an animal at sea level. Nice beach cruise today, car performed flawlessly!

Nick · 09-05-2005

Sounds like you have a small vacuum leak. And yes, these cars LOVE nice, cool, dense sea level air!

cuisinartvette · 09-05-2005

I don't even know where to start looking! All the vacuum lines and secondary parts (I'm pretty sure) were replaced along with the coils before I bought the car. I'll spend more time on it tomorrow and get back to you guys.

tomtom72 · 09-06-2005

Hi Cuisinartvette, There is an article in the "how to" section of the ZR-1 Net Registry. Or you can go to Corvette Action Center.com and look in the C4 / ZR-1 section, it's a sticky I believe. Some useful info there that might help you figure if the leak is under the plenum or the pump is at fault.

Basically there is a vac line on passenger side of plenum that comes out near the IAC motor and has a connector splice. Separate it & put the Vac pump on the end going under the plenum and put some vacuum into the system under the plenum & see what's up. The other part of the spliced line goes to the vac pump @ the overflow tank, just toward the front next to the horn.
I'm not sure what amount of vac the system is supposed to hold, I can look it up for ya if need be. But fighue it should hold at least 17"hg, I would think.

Tom

cuisinartvette · 09-06-2005

TomTOm-Thanks for the tip!

Patton · 09-06-2005

The systems holds 10-12hgs...

Cuisinart, I am going through the SAME problems right now... We should definetly talk and share knowledge. I have found several write ups and walkthroughs on how to diagnos and repair/replace every aspect of the secondary vacuum system. I found all the hard to find parts as well. I am to the point where I have the knowledge and tools I need for the job, now I am just waiting for my parts to arrive before I pop the plenum off and get dirty.

Here are a couple of great links I have found for our problem.
http://www.corvetteactioncenter.com/...ad.php?t=14272
http://www.pnwzr1.net/PNWZR1.htm

I got my vacuum hand pump at sears (50$) at tested my lines, I have a leak under the plenum and my pump is burned out...
go to here http://www.partszoneonline.com/ for your parts needs, checkout my thread "check engine soon" for all the part numbers, also the part numbers are listed in the CAC link i mentioned before... Let me know how you are doing on it and good luck!

Scoob · 09-07-2005

Quote:

Originally Posted by cuisinartvette

Also, is it common for the doorlock mechanisms to get sticky? Keyless wasn't opening them. You can hear it, but they don't go. Got inside, flipped the lock switch back and forth a 1/2 dozen times and they freed up. Went to lock it with keyless, same thing. Is this an easy fix or am I buying something?

Keyless? Afaik, keyless entry was not an option in '90.

cuisinartvette · 09-07-2005

Has an Ungo alarm with keyless entry. I really don't want to tear into a door panel if I don't have to (If I tough something delicate it breaks), but if I'm there can they be cleaned and lubed or do I have to replace solenoids?

Afaik?

09-06-2005	#14
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,609	Secondary Port Vac sys. Hi Cuisinartvette, There is an article in the "how to" section of the ZR-1 Net Registry. Or you can go to Corvette Action Center.com and look in the C4 / ZR-1 section, it's a sticky I believe. Some useful info there that might help you figure if the leak is under the plenum or the pump is at fault. Basically there is a vac line on passenger side of plenum that comes out near the IAC motor and has a connector splice. Separate it & put the Vac pump on the end going under the plenum and put some vacuum into the system under the plenum & see what's up. The other part of the spliced line goes to the vac pump @ the overflow tank, just toward the front next to the horn. I'm not sure what amount of vac the system is supposed to hold, I can look it up for ya if need be. But fighue it should hold at least 17"hg, I would think. Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

09-05-2005	#11
cuisinartvette Join Date: Aug 2005 Location: San Fernando Valley, CA. Posts: 896	Ok, after coming back from a long drive, I parked it and shut it off. Withthe key in the ON position, I heard from the front pass. side what I'm assuming was the pump ecery 10 seocnds or so. The pump was on for a fraction of a second. Did that twice-Was kind of in a hurry so I didn'y check it with the motor running. I should have a minute or two tomorrow to go play with it some more. Also, is it common for the doorlock mechanisms to get sticky? Keyless wasn't opening them. You can hear it, but they don't go. Got inside, flipped the lock switch back and forth a 1/2 dozen times and they freed up. Went to lock it with keyless, same thing. Is this an easy fix or am I buying something? Gotta say, this thing is an animal at sea level. Nice beach cruise today, car performed flawlessly!

09-05-2005	#12
Nick Join Date: Jul 2005 Location: Auburn, Washington Posts: 585	Sounds like you have a small vacuum leak. And yes, these cars LOVE nice, cool, dense sea level air!

09-06-2005	#16
Patton Join Date: Dec 2003 Location: Sacramento, CA Posts: 220	The systems holds 10-12hgs... Cuisinart, I am going through the SAME problems right now... We should definetly talk and share knowledge. I have found several write ups and walkthroughs on how to diagnos and repair/replace every aspect of the secondary vacuum system. I found all the hard to find parts as well. I am to the point where I have the knowledge and tools I need for the job, now I am just waiting for my parts to arrive before I pop the plenum off and get dirty. Here are a couple of great links I have found for our problem. http://www.corvetteactioncenter.com/...ad.php?t=14272 http://www.pnwzr1.net/PNWZR1.htm I got my vacuum hand pump at sears (50$) at tested my lines, I have a leak under the plenum and my pump is burned out... go to here http://www.partszoneonline.com/ for your parts needs, checkout my thread "check engine soon" for all the part numbers, also the part numbers are listed in the CAC link i mentioned before... Let me know how you are doing on it and good luck!

09-07-2005	#18
cuisinartvette Join Date: Aug 2005 Location: San Fernando Valley, CA. Posts: 896	Has an Ungo alarm with keyless entry. I really don't want to tear into a door panel if I don't have to (If I tough something delicate it breaks), but if I'm there can they be cleaned and lubed or do I have to replace solenoids? Afaik?