front pcv affecting mafs?

[dinoxor]

So I have been searching for quite a while now on here and on TN forum but was not able to find any answers in regards to what this thing is called and its purpose!



Is it similar to the rear pcv where pressurized air within the crankcase is released?
Or I think I read in some forum where air travels into the front section of the crankcase and then it is released from the rear.

But I'm going to assume that air escapes from here carrying oil vapor in the process since someone here made an oil catch can.
With that being said, is it possible that the oil vapor is spewing into my mafs?

Every once in a while my check engine lights turns on but disappears after 200 miles.
and every time I check it throws a p0171 code where my car is running lean.
I read somewhere that a dirty mafs MAY be the culprit.
in addition my K&N cone filter is larger than the standard filter that was given and is NOT an oiless filter

any insight can help clear my confusion.
Thanks!

[PlateLunch]

I believe it recycles the air/gas from your crankcase just like the pcv valve. Pop your filter off and check the inlet hole for it, mine will usually have a couple small oil drops kind of running down down the side. I don't think that is that much of and issue unless you have a shartload of oil coating your intake, which would mean your getting serious blowby and that would probably screw with your MAF. I know that when I re-oiled my K&N the first time I WAY over oiled it and it sucked some into my MAF, I just got some MAF cleaner and washed and re-oiled the filter and the problem was solved. If you haven't cleaned your MAF ever, might as well.

One more thing, I think that sometimes the ecu will read lean because of the larger amount of air from the Injen/K&N combined with the an N/A stock engine. Pull the EFI fuse for a minute and replace to reset the fuel system and engine light. This was happening to me with an Injen/CAI/K&N combo before I went boosted.

Hope this might help.

[trd4life]

its def. bad for the maf. run that hose to a catch can and then another line to the injen

[sliDingSolAra...]

i get P071 and P072 if rev the crap out my engine and/or bounce off redline. usually goes away pretty quickly.

but that hose connecting to the intake WILL pull oil out of the engine and blow it past the MAF. like Gabe said put a catch can in between the two, but make sure the catch can has a piece of steel wool in the top of the can, (most cans do not come with a baffle inside of them. otherwise oil can still be pull through and thrown at the MAF)

platelunch is also spot on, do what he says to clean up the MAF. i don't how your driving habits are but if like to play race-car then these things happen frequently

[dinoxor]

Thanks for the response!

Yeah I cleaned my mafs around august before installing my intake not sure how frequent I should clean it though

I guess a catch can will be the best option but I was planning on doing something a little easier like this:
http://www.toyotanation.com/forum/103-3 ... mz-fe.html

Is recycling the air that necessary? since this seems to be the easier option

[PlateLunch]

All I can think of is the vacuum within the entire system, as doing this seem like it would interrupt it. I'm sure the other guys will now for sure and on another note, after this thread I think I'm going to install a catch can on the ride. You can pick them up on ebay $16-40.

[dinoxor]

hold your money platelunch!

I found this just a while ago D:
viewtopic.php?f=2&t=42428&start=30
read the last post from 02slera

and slidingsolara you even questioned if your catch can is even working
since it's been about a year did your catch can work?

[PlateLunch]

Nice research! I wonder if putting a catchcan after the PCV valve would affect my S/C output? It seems like that line is actually sucking IN air from the intake, but I'm going to pull it off with my engine running and check whether it's pushing or pulling air. I'll letcha know

[GzNutz]

The pcv valve is a one way valve. It only lets air back to the intake. There isn't a need for a catch can on that hose because the air is not metered, enters the intake after the maf. Only good place for the can is the front pcv hose that dumps in before the maf.

[sliDingSolAra...]

hold your money platelunch!

and slidingsolara you even questioned if your catch can is even working
since it's been about a year did your catch can work?

ya i did question it, my knowledge on catch cans was next to nothing beside knowing that they "catch stuff" lol. but after looking at other cars that use them and talking to guys at car shows who use them i learned where they are most effective. since most of our cars are at least 12+ years old they tend to have "blow by" if the cars is not maintained properly and driven hard constantly. blow by, by definition is when your piston rings are worn to the point where oil is forced past the rings into the combustion chamber or into the crankcase depending on the stroke. but for the use of a catch can the oil from the top of the heads is forced out the pcv into the intake simply because of engine vacuum. so in order to prevent the oil from fouling the MAF a catch is used to collect the oil.

MOST IMPORTANT THING IVE NOTICED ABOUT CATCH CANS IS THE USE OF A BAFFLE INSIDE THE CAN ITSELF.

now i cannot vouch for other brands but i know for a fact that ebay catch cans do not have any baffles. i own a NRG can which is only a can with a hollow interior. there are more expensive ones like Greddy and HKS, for a well know name like that i hope they use baffles, but i cannot say.

when i purchased my shiny NRG can it came without a baffle inside, so it just had a inlet port and outlet port right next to each other. now think about that for minute, if the engine is under vacuum and air is being sucked into the intake how could a simple can with hoses just collect the oil??? the oil could simply just go in the can and right out because the ports are so damn close together. THIS IS WHERE A BAFFLE COMES INTO PLAY. now i've noticed most muscle car guys, and any guy with a V8 or a boosted set-up(no matter what the engine) will use STEEL WOOL as a baffle inside the catch can. most say they just let the steel wool get pinched at the top of the can when they screw the top down. this lets the oil strain through the wool and collect at the bottom not allowing the oil do a quick in/out move, u know?


now with my set-up i failed to use the steel wool until about a month or so ago. BUT i did check it before that and honest to god the $80 can was BONE DRY!!!! upon inspection of my injen SRI i noticed a oil stream in the SRI coming from the hose where the front valve covers PCV comes from. hence my can was doing nothing at all.

i hope this helps a little, its 1am here and i just got home from work so any typos or sentances that don't make sense are just me dozing off

again what i've learned is from word of mouth. your set-up may not even need a catch can, unless you want to add some bling to your engine bay.


Once again i know this is a very long post but hey, we're all learning!!!! this is just the knowledge i've collected. i think it's pretty accurate but if anyone disagrees please chime in!!!

[PlateLunch]

^^^Nice info!!! I read about the baffling and it seems like it's the way to go, especially since you were still getting blow by. Looks like i'll save up for the black NRG and forgo the ebay cheapy. Thanks for the advice

[sliDingSolAra...]

no prob, happy i could help!

[dinoxor]

Thanks for the input!!

Upon inspection today, I came across this...




you can see a thin layer of oil from the left hole and a small stream leading to the throttle body

So it's true I guess I'll have to resort to a catch can

However I'll use the following diy write-up but with some minor changes:
http://forums.evolutionm.net/evo-how-to ... -tube.html

Just some slight modification from what slidingsolara mentioned earlier,
1) I will still buy a cheapo depo oil catch can similar to the link I posted as long as I'm able to have access to the inside of the can
2) I will not use steel wool but rather steel scouring pads as shown in the link

just a side note, steel wool is NOT the same as steel scouring pads.
steel wools are smaller and finer strands of steel that may cause the following problem
a) small pieces may get sucked into the intake and into your combustion chamber
b) hot blow-by air will pass through and steel wool burns easily! (learned this from boy scouts as steel wool is used for tinder to start fire)

Since I don't have a drill press I'll just use a simple divider inside the can scouring pads near the bottom to act as a filter for the inlet and outlet.
Hopefully I'll start this soon and if time allows post a diy

[PlateLunch]

Nice work! Def get a DIY going, I'll be doing the same after I get this AFL gauge in!

[Brandoe91]

For me the Injen intake was the cause of the P0171 code; switching back to the stock intake setup got rid of the code permanently. For some weird reason some Solara's with the Injen intake throw the P0171 and some don't. If you wish to keep the Injen intake, you will need a piggyback to counter the lean condition. As for the oil in the intake track, the rear PCV valve might be stuck closed causing the oil to vent through the breather.