I added a breather filter 2 days ago and just had my Service Engine Soon light come on. Has anyone had this problem? I took the breather filter off and put the stock tube back on and reset the ECU and the light has not come on again.

 

I have a breather filter with no SES

 

Same here. Don't put it back on and be glad it was cheap. The SES code was probably for some type of misfire. It's caused by unmetered air entering the system.

 

I have a breather too.. NO SES light here.. That's weird why it would set off one..

 

blu & PCGuRu2K mine lasted 3wks to a month before it threw a code. Had a scanner hooked up and after reseting it came right back. Took it off and no probs since.

 

Had mine on for about 3 months no probs yet maybe Im lucky

 

I had mines on since the blower.. No SES light..

But then again I pulled out my SES light because it would always stay on with my auto ecu & 5spd tranny

 

Maybe so. If you get a code that is the 1st place to look.
I would also think that other peps that have some type fuel management could get way with one.

 

Have breather for one month, no probs yet.

 

I think we discussed this briefly in another thread, but could you explain again how unmetered air is entering the system. I'm don't think I understood last time. Thanks

 

I dont understand how only a few of us got got the SES light; but anyway it's back to normal and hoping it stays like that. Thanx for your posts.

 

are breathers better for your car????

 

Ok, once air passes the MAF it's metered. The ECU probably has a multiplier of some kind to show the amount of air going to the manifold and breather. Lets say the meter is showing 100 the ECU will then take a percentage of like 95% to the manifold and 5% to the breather. i.e. 100x.95=95 to the manifold and 5 to the breather. (These numbers are just an example, I have no knowledge of the true figures)
Now when you disconnect the breather line plug it and put the breather filter on the valve cover you’re letting un-metered air into the valve train and 100% of the air goes to the intake manifold. The ECU does not see the increased flow and you run lean causing a random or cylinder specific misfire, which then throws a code.

The way around it is to richen the mixture.

The reason people don't see it right away, at the same point or at all is because the ECU isn't linear, it optimizes the engine to your driving style and a few other variables.

 

TOLD YOU SO!!!

Benefits of the breather filter is a cleaner TB since this vented air is not recycled back in the system..

Drawbacks, SES light, and other problems..

ED

 

I was under the impression that air flowed from the crankcase, throught the breather tube and into the thottle body and intake manifold. If I understand what you said, air is flowing the other direction. If that's the case then why does everyone say one of the benefits of a breather filter is a cleaner throttle body and intake manifold?

 

Ive had this setup for about 6 months now and no SES due to it. I threw one but it was a bad O2 sensor...

 

Air travels back and forth through the line depending on throttle position and pressure. I'm also not saying I have the info right on the money, I may have the flow backwards. Either way when you put the filter on you're tricking the ECU. All the people that have used one and got a code show the same type of code, misfire. Maybe the Nissan tech that is an .org member from the northeast can shed some more light on this. (I forget his name but he is from VA)

For the people using one and are code free good for you and I hope it stays that way. I've even thought about an inline filter as a way to keep the TB cleaner but I figure it will get cloged rather quickly.

 

Crankcase ventilation allows for fumes, spent gases, etc. to be burned clean by introducing them to the intake charge. This in turn dumps hot and dirty air into your intake. You should be able to put a breather element (filter) on the crankcase tube without issues. You MUST however cap off the line (or port) going into the intake so it doesn't draw unmetered air.