Possible PCV valve, vacuum problems
03-31-2013, 07:31 PM
#1
Registered User
Thread Starter
Join Date: Jan 2013
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
Possible PCV valve, vacuum problems Hey guys
I have a 95 z/28 that i have had for about two months. I bought the car with 118,000 miles. Shortly after I purchased the car I noticed it was blowing bluish smoke out of the exhaust under hard acceleration over 3,000 RPMs. I took it to a local shop to a have a leak down and compression test done thinking that the motor had bad rings. The shop told me it had great compression but someone had removed the PCV valve and that was causing oil to get sucked into the intake and that was what was causing the blue smoke. He also said that because he didn't know how long the car has had this problem that it may continue to smoke for a while until the old oil burns out of the exhaust system.
Ever since i had the PCV valve put back on it runs rough when cold. idle bounces around from 500-1000 until warm. I put an ethanol equalizer in my fuel that helps with this. Without the equalizer the car won't run well enough to drive until warm, then it's perfectly fine. About three weeks later I had the oil changed by a mechanic who is a friend of mine and he checked the PCV valve that i had installed and said that it had no vacuum. I asked him to try and track down why it didn't have vacuum and he told me he couldn't figure it out. He thinks someone has disconnected something somewhere but he didn't know for sure. It seems to me if the PCV valve was the culprit but it has no vacuum then the problem with the oil in the intake is still going on.
I have chrome exhaust tips that I try to keep clean but after about a weeks use they are black again. I would like to try and figure this problem out. The compression test was good so rings are unlikely, it's not smoking under decel so valve seats are unlikely. Hopefully someone here can get me pointed in the right direction.
Also the car has a gutted cat and i think it is running rich, my fuel economy is rather poor and I am always smelling a strong exhaust odor when driving.
Btw the car is a cammed 6 speed if that matters
Thanks in advance for the help
I have a 95 z/28 that i have had for about two months. I bought the car with 118,000 miles. Shortly after I purchased the car I noticed it was blowing bluish smoke out of the exhaust under hard acceleration over 3,000 RPMs. I took it to a local shop to a have a leak down and compression test done thinking that the motor had bad rings. The shop told me it had great compression but someone had removed the PCV valve and that was causing oil to get sucked into the intake and that was what was causing the blue smoke. He also said that because he didn't know how long the car has had this problem that it may continue to smoke for a while until the old oil burns out of the exhaust system.
Ever since i had the PCV valve put back on it runs rough when cold. idle bounces around from 500-1000 until warm. I put an ethanol equalizer in my fuel that helps with this. Without the equalizer the car won't run well enough to drive until warm, then it's perfectly fine. About three weeks later I had the oil changed by a mechanic who is a friend of mine and he checked the PCV valve that i had installed and said that it had no vacuum. I asked him to try and track down why it didn't have vacuum and he told me he couldn't figure it out. He thinks someone has disconnected something somewhere but he didn't know for sure. It seems to me if the PCV valve was the culprit but it has no vacuum then the problem with the oil in the intake is still going on.
I have chrome exhaust tips that I try to keep clean but after about a weeks use they are black again. I would like to try and figure this problem out. The compression test was good so rings are unlikely, it's not smoking under decel so valve seats are unlikely. Hopefully someone here can get me pointed in the right direction.
Also the car has a gutted cat and i think it is running rich, my fuel economy is rather poor and I am always smelling a strong exhaust odor when driving.
Btw the car is a cammed 6 speed if that matters
Thanks in advance for the help
03-31-2013, 10:28 PM
#3
TECH Veteran
Be sure people did the PCV correctly. The valve is in the LH side of the intake manifold. There is not supposed to be a valve in the valve cover where a lot of earlier cars had them. A mechanic not familiar with the LT1 could have told you wrong.
The hose from the valve cover to the TB is unrestricted. A 90° plastic elbow fits in the RH valve cover on the end of the hose.
The hose from the valve cover to the TB is unrestricted. A 90° plastic elbow fits in the RH valve cover on the end of the hose.
04-01-2013, 07:46 AM
#5
Registered User
Thread Starter
Join Date: Jan 2013
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
Be sure people did the PCV correctly. The valve is in the LH side of the intake manifold. There is not supposed to be a valve in the valve cover where a lot of earlier cars had them. A mechanic not familiar with the LT1 could have told you wrong.
The hose from the valve cover to the TB is unrestricted. A 90° plastic elbow fits in the RH valve cover on the end of the hose.
The hose from the valve cover to the TB is unrestricted. A 90° plastic elbow fits in the RH valve cover on the end of the hose.
