Hello people, I was having a problem, my Altima v6 was throwing a lot of smoke by the exhausts, white smoke. After some investigation, i realized that the blow-by hose, connected in the bank 1 to the PCV valve (and the manifold to the other side), was the one causing this. So I disconnected it from the manifold, and I put a "blocker" (i dont know how to call it, english is not my native language) in the manifold to stop the vacuum leak.
However, there is smoke coming from the blow-by hose (pcv system), and if i connect it, the exhaust will throw A LOT of smoke.

Why is there smoke?
I changed the pcv valve and it still continues to throw smoke.

As a note, after i disconnected the hose, it took around 30 minutes to stop the exhaust from throwing smoke.

Thanks for any opinion!

Sorry to read about the issues. When you replaced your PCV valve, was the old one covered in a lot of oil by any chance? I'm not sure what's up here, but it seems like you may have some sort of internal leaking somewhere. I'd see about getting the FSM (look here:http://www.nicoclub.com/FSM/Altima/2011%20altima/) and look into inspecting the PCV system components and hoses. Also, I'd be concerned about my oil and engine and would think about having a compression test done on each cylinder. The code for your sensor could be due to too much crap in your exhaust gases, so I'd wait to replace that sensor for a while.

Is your car an automatic and where are you located?

Hello Centralcoaster, thank you for your answer.

Yes, the old one seemed to be clogged with oil. I already looked a little bit into the hoses, I found that there's oil in here https://drive.google.com/open?id=149bI7 ... 0FH7oE25a-
https://drive.google.com/open?id=1DTYGs ... bulhvN2JTw

I found oil and some smoke in there.

It's the box that goes connected to the air hose intake after the filter, but i don't know what's this box for, is it for chance an oil/air separator? if it is, then that might be the problem, I will try dissasembling it tomorrow from the other side to see if i see oil in there. I have been looking in the manuals but there's no description for this item
Looked in the EC and EM manuals.

Yeah, i'm not thinking in changing the o2 sensor, i don't think it's failing, i will first look for this problem

I will be checking this box that i don't know what it does, and if i dont get to anywhere with it, i will try a compression test I guess
Yes, it is automatic, in fact, CVT

Thank you again for you answer
and greetings from Mexico!

Oh, and i discovered that there was some smoke too coming from the oil cap when open, however, i don't feel any pressure.

So, it smokes from the blow by hose that is disconnected right now, from the oil cap, and from that hose that i don't know what is it.
I guess there must be something wrong with the pcv system or the compression (hope not)

If smoking out the tailpipes then you are utterly killing your cat.

Proper PCV................a hose runs from a filter somewhere at the aircleaner box or similar, it runs into engine and then another hose comes out of it at the PCV and then that hose MUST attach to the intake in some way. Any other way and the system is not sucking correctly and you will get smoke out of the wrong places.

Past that a compression test like said, the engine is worn enough to smoke and new engine time if so.

Hello amc49, I know that the hose from the pcv should be connected to the intake, but if done, the tailpipes will start releasing a lot of smoke and even the car will misfire, connecting it right now as it is, is not an option due to this.

The only thing i can think of is excessive blow-by.

By the way, do you know what does the box (breather hose) attached to the air duct (just after the air filter, before the throttle plate) is for? I found some oil in there, and i think it shouldn't be there

It is the front half of the PCV system. Air flows from airbox into motor then out PCV and into intake. At higher flows like deeper in throttle the front end also blows backwards into airbox once the blowby passes the amount the PCV can pass into intake.

If hooking up PCV to intake then carries a lot of oil to the engine, it is likely in bad shape. Possibly the oil is overfilled, that can do it. If the OEM locations have been messed with like removing an oil separator or the like that can do it too, the OEM PCV location is baffled and situated to not pull oil so pulling it will be a problem there.

Seems like a good amount of oil crud has had a chance to build up in your engine. I'd probably run a couple of engine oil flush cycles to clean up the inside. Then I'd take apart a bit of the intake, throttle body, valve cover and maybe even the EVAP box before the valve. I'd clean all that real nice, put it back with fresh seals/ RTV. Sounds like a neglected engine and possible overfills in the past. A tune up is likely in order after cleaning up the built up gunk. To really get into it without a rebuild, you can pull the engine, take off the pan and covers and clean a little extra in there, reassemble and reseal. That might be overkill if your not doing other things though.

' I'd probably run a couple of engine oil flush cycles to clean up the inside.'

I always used to ask people why they did that when I was in parts. Where do you think any loosened up material is going to go?, not nearly all of it will end up drained. Best way to take out engine bearings I can think of. We absolutely never looked to 'clean up' an engine inside at the family garage, you yank it and take it apart to do that. X2 to sentence #3 there.

Of course, my view only, people can tear up their cars however they please, I saw enough of it. Certainly no personal insult intended or implied toward anyone.

By now people are likely thinking I didn't sell a lot of automotive maintenance chemicals and I didn't, I felt most of them were morally wrong and a waste of money and talking to the sales reps only cemented that hard in place. I prefer to fix things correctly or work around issues like that in other ways and no troubles doing it and so much money saved as well I cannot overstate it.

amc49, I don't follow, maybe the OP does. I see some explanation and some experience, but in relation to what I'm not sure. I can find several third sentences of ______ (paragraph, post, thread).

For speedy bearing cleanup, are you using this engine scrub? http://kalecoauto.com/index.php?main_pa ... ucts_id=25

Back on topic, I thought he has some sludge in the wrong places, possibly defeating the baffles and letting oil accumulate and find it's way towards the intake system. He doesn't have ancient seals, so loosening that stuff up and cleaning it out where accessible (remove covers) while using a few filters to clean what can't be reached easily (flush) seems like that would be useful. What are you recommending and what are you not recommending for the issue specifically?

Hello guys! Sorry for the late response, my problem of the smoke has been now fixed.

I changed the valve cover, I bought it original from nissan with its new gaskets. Here in Mexico, the valve cover (the one that has the PCV valve) was $1201 MEXICAN pesos, which is maybe around 60 dollars (it included the PCV valve). The gaskets, were of course a lot cheaper, around $200 mexican pesos (around 10 dollars), and the installation of it with a mechanic was $350 mexican pesos, which is around 17 dollars.

With this, my smoke problem has been fixed, however, I still have a code i had before, which is p2a00, I thought this could might fix the code but it didn't

After some research, i found that is mostly caused by an exhaust leak, so i will be looking for it in the next weeks

Thank you guys for answering my topic, when i get the p2a00 fixed i will let you know

I edit a LOT as I think further on a subject and I as well feel if I say something it needs to be correct and I rethink my answers often more than once for it. Just like when working on the cars and hundred foot long printing presses and why it worked out so very well. People who post with no real thinking are dangerous.

In relation to what? Scads of money suddenly freed up to do other things with. Flushing will not help a dying engine that has been mistreated as deposits are a long term negligence issue and the clock cannot be rolled back on that. And why flush a newer one? It OFTEN leads to later damage like the ATX flushes commonly do. The person getting your cash for it will never admit to that of course.

Me? After a critical look at the PCV system for errors (common) yank valve cover and clean the baffle portion. Reinstall. If needed then figure out how to detach baffle and clean it separately, they built valve cover (if a unitized part) and you can do whatever they can. There was no need to buy one at all there, at least not in my world.