83 280zx pcv
10-27-2013, 02:24 PM
#1
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83 280zx pcv
I used the search tool and didn't find a thread on the PCV valve. I also looked through the Haynes.
The engine idles somewhat rough, but not too bad. I figured I would check some of these vacuum components and such.
Well, I check the EGR valve, it was good. I followed the Haynes and it says to first check engine off and make sure the valve will open and then engine on to see if it will open again. It tried stalling as advertised in the Haynes.
Then I went to check the PCV valve. Page 139, step 2 and 3, of the Haynes says to pull the hose that's connected to the air duct and goes to the valve cover to check for vacuum. I did so but I couldn't even check for a vacuum because the engine stalled so fast.
Then I pulled the hose connected to the PCV valve, the engine started to stall but I was able to get my thumb on the end of the valve and felt a strong suction but then it stalled.
I'm seeing mixed info on the internet. Makes me wonder if every car is a little different from the next. I've pulled the pvc to my bronco before and it doesn't stall. Is the Z car supposed to stall when I pull the hose from the PCV valve?
The engine idles somewhat rough, but not too bad. I figured I would check some of these vacuum components and such.
Well, I check the EGR valve, it was good. I followed the Haynes and it says to first check engine off and make sure the valve will open and then engine on to see if it will open again. It tried stalling as advertised in the Haynes.
Then I went to check the PCV valve. Page 139, step 2 and 3, of the Haynes says to pull the hose that's connected to the air duct and goes to the valve cover to check for vacuum. I did so but I couldn't even check for a vacuum because the engine stalled so fast.
Then I pulled the hose connected to the PCV valve, the engine started to stall but I was able to get my thumb on the end of the valve and felt a strong suction but then it stalled.
I'm seeing mixed info on the internet. Makes me wonder if every car is a little different from the next. I've pulled the pvc to my bronco before and it doesn't stall. Is the Z car supposed to stall when I pull the hose from the PCV valve?
10-27-2013, 02:32 PM
#2
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Location: Tacoma, WA
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I think so, but i have no idea why, I have heard people say that if you pull the dipstick while the engine is running that it will, and should die. and they both connect to the engine internals.
buy a vacuum gauge, hook it up to a vacuum hose, run the engine and look to see if the needle stays steady in the middle, if it doesn't then look online at what various vacuum gauge readings mean to find your problem. that haynes manual may even give little pictures of what the different meanings mean.
buy a vacuum gauge, hook it up to a vacuum hose, run the engine and look to see if the needle stays steady in the middle, if it doesn't then look online at what various vacuum gauge readings mean to find your problem. that haynes manual may even give little pictures of what the different meanings mean.
10-27-2013, 06:58 PM
#3
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I used the search tool and didn't find a thread on the PCV valve. I also looked through the Haynes.
The engine idles somewhat rough, but not too bad. I figured I would check some of these vacuum components and such.
Well, I check the EGR valve, it was good. I followed the Haynes and it says to first check engine off and make sure the valve will open and then engine on to see if it will open again. It tried stalling as advertised in the Haynes.
Then I went to check the PCV valve. Page 139, step 2 and 3, of the Haynes says to pull the hose that's connected to the air duct and goes to the valve cover to check for vacuum. I did so but I couldn't even check for a vacuum because the engine stalled so fast.
Then I pulled the hose connected to the PCV valve, the engine started to stall but I was able to get my thumb on the end of the valve and felt a strong suction but then it stalled.
I'm seeing mixed info on the internet. Makes me wonder if every car is a little different from the next. I've pulled the pvc to my bronco before and it doesn't stall. Is the Z car supposed to stall when I pull the hose from the PCV valve?
The engine idles somewhat rough, but not too bad. I figured I would check some of these vacuum components and such.
Well, I check the EGR valve, it was good. I followed the Haynes and it says to first check engine off and make sure the valve will open and then engine on to see if it will open again. It tried stalling as advertised in the Haynes.
Then I went to check the PCV valve. Page 139, step 2 and 3, of the Haynes says to pull the hose that's connected to the air duct and goes to the valve cover to check for vacuum. I did so but I couldn't even check for a vacuum because the engine stalled so fast.
Then I pulled the hose connected to the PCV valve, the engine started to stall but I was able to get my thumb on the end of the valve and felt a strong suction but then it stalled.
I'm seeing mixed info on the internet. Makes me wonder if every car is a little different from the next. I've pulled the pvc to my bronco before and it doesn't stall. Is the Z car supposed to stall when I pull the hose from the PCV valve?
Regardless, the PCV is like a $6 part. Take 30mins out of the day and replace it so you don't have to worry about it. It's usually the most overlooked piece of vacuum equipment on these engines. Awkward placement under the intake manifold so most people pay no attention to it!
10-28-2013, 07:23 AM
#4
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if you remove the oil cap with the engine running, does it stall?
Regardless, the PCV is like a $6 part. Take 30mins out of the day and replace it so you don't have to worry about it. It's usually the most overlooked piece of vacuum equipment on these engines. Awkward placement under the intake manifold so most people pay no attention to it!
Regardless, the PCV is like a $6 part. Take 30mins out of the day and replace it so you don't have to worry about it. It's usually the most overlooked piece of vacuum equipment on these engines. Awkward placement under the intake manifold so most people pay no attention to it!
I tried it and it hesitated continuously. I had it off for a good 20 seconds but no stall but it sounded like it was awfully close to stalling so I'm not sure how to classify that.
Yea, I know the PCV valve is a cheap part, even at Autozone it's only $3, and I'll probably just go ahead and replace it if I don't identify the problem anytime soon. I was just hoping I could learn something. I was even hoping to save on the $3, trip to the store, and the 10 minutes to replace the old one.
Anyways, I find it interesting that pulling the oil cap the engine didn't stall right away while pulling the hose at the air duct that leads to the valve cover stalls it super fast.
10-29-2013, 06:26 AM
#5
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well, pulling the hose from the valve cover to the intake would cause the engine to stall out because that big hose goes directly into the intake manifold so you are creating a huge vacuum leak when you disconnect it.
10-29-2013, 06:31 AM
#6
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That end of the hose wasn't pulled, the other end that goes to the air duct was pulled (I followed the Haynes). Also, the explanation doesn't make sense because why would it stall if you pull that end of the hose that goes to the valve cover but the oil cap on the valve cover doesn't stall the engine when removed.
10-29-2013, 06:49 AM
#7
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Im not certain, but i don't think it stalled out because the hose that goes into the valve cover doesn't just go directly into the engine, it has baffle plates and stuff that may reduce the vacuum leak. also, I don't understand what you are saying, it doesn't matter where you disconnect a hose that connects to the intake, your still creating a leak no matter what.
10-29-2013, 09:24 AM
#8
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Im not certain, but i don't think it stalled out because the hose that goes into the valve cover doesn't just go directly into the engine, it has baffle plates and stuff that may reduce the vacuum leak. also, I don't understand what you are saying, it doesn't matter where you disconnect a hose that connects to the intake, your still creating a leak no matter what.
10-31-2013, 01:29 AM
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All my L28's don't stall when the oil cap is removed. It shouldn't, you're venting crankcase pressure instantly when you do this and the PCV will be closed. I asked you to remove it because it's usually a half assed test to see if your PCV may be somewhat stuck open (which I'm pretty sure it is if your car stumbled a bit when removing the oil cap).
I can do all the explaining in the world, but if it's already written somewhere out there, I ain't wastin time.
Positive Crankcase Ventilation (PCV)
Combustion blow by passes out of the valve cover breather and gets "vacuumed" into the intake to be reburned by the air duct. That's it. Unlike your bronco which has the PCV on the valve cover, the L28's just have a breather, to attach a hose to, to go into the air duct. With the actual PCV underneath the intake manifold. If the PCV is stuck open, you'll be accepting far more blow by gasses than normal and you'll get a rough idle, running, etc.
As long as your PCV isn't stuck SHUT - then you'd be blowing out your oil seals because your entire crankcase would pressurize = oil leaks everywhere.
I can do all the explaining in the world, but if it's already written somewhere out there, I ain't wastin time.
Positive Crankcase Ventilation (PCV)
Combustion blow by passes out of the valve cover breather and gets "vacuumed" into the intake to be reburned by the air duct. That's it. Unlike your bronco which has the PCV on the valve cover, the L28's just have a breather, to attach a hose to, to go into the air duct. With the actual PCV underneath the intake manifold. If the PCV is stuck open, you'll be accepting far more blow by gasses than normal and you'll get a rough idle, running, etc.
As long as your PCV isn't stuck SHUT - then you'd be blowing out your oil seals because your entire crankcase would pressurize = oil leaks everywhere.
11-03-2013, 10:40 AM
#11
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I replaced the PCV valve. I removed the oil cap again just to see what happens. Before I said it hesitated but right now it sounds a lot less like hesitation to stall but more like significant reduction in idle speed. Is that possible?
I also reduced the idle yesterday, it was probably around 900 and I got it closer to 700 now.
I also reduced the idle yesterday, it was probably around 900 and I got it closer to 700 now.
11-03-2013, 02:55 PM
#12
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Shouldn't be a significant enough change in idle that it's THAT noticeable.
Check for vacuum leaks elsewhere. Take some break cleaner and spray in very short bursts around vacuum lines, etc. Check around the fuel injectors, AAC, etc. Idle will raise and engine will smooth out when you've found your leak.
Check for vacuum leaks elsewhere. Take some break cleaner and spray in very short bursts around vacuum lines, etc. Check around the fuel injectors, AAC, etc. Idle will raise and engine will smooth out when you've found your leak.
11-04-2013, 01:46 PM
#13
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Shouldn't be a significant enough change in idle that it's THAT noticeable.
Check for vacuum leaks elsewhere. Take some break cleaner and spray in very short bursts around vacuum lines, etc. Check around the fuel injectors, AAC, etc. Idle will raise and engine will smooth out when you've found your leak.
Check for vacuum leaks elsewhere. Take some break cleaner and spray in very short bursts around vacuum lines, etc. Check around the fuel injectors, AAC, etc. Idle will raise and engine will smooth out when you've found your leak.
Edit, looks like the auxiliary air control valve is on turbo models only. Correct me if I'm wrong.
Also, how come break cleaner is suggested to use around vacuum lines? If I spray it around an area that's leaking, will it get sucked inside the engine? Could that be bad?
Last edited by jmw_man; 11-05-2013 at 07:11 AM.
11-08-2013, 06:12 AM
#15
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As for the brake cleaner, I learned that there's chlorinated and non-chlorinated. One is flammable and one is not flammable. Using the non-flammable would be bad. I updated by project car thread, I'm going to try to keep my info in there.
