IS250DIYER

I wish i had a soild awnser with proof but i dont. I had all the same symptoms as his and after i took the occ out everything went back to normal. It worked for me so i figured id share my experience and at least try to help someone out. I guess we will see if he takes it out and shares his results. 95% sure everything will better.

2013FSport

iTrader: (2)

If you think about what the MAF does, it informs the ECU how much air volume there is for combustion. The valve cover connection to the accordion hose is **potentially** unmetered air **if** the connection to it has any kind of air leak. This can throw the trims off.

OP could perhaps leave all the plumbing and OCC in place, but restore the original connections and test it.

IS250DIYER

You can leave everything right where it is just disconnect the hoses, then replace with original factory hoses from pcv to plenum (drivers side on motor) and from valve cover to air intake tube (passenger side on motor). I have a valve installed inline with my pcv to plenum hose and drove the car a few times with the valve slightly closed of more and more but never shut. Different spots gave the exhaust different notes tones sounds....whatever u want to call it and i could tell a difference on take off or top end depending on if it was open more or closed more.

rbipu

Many thanks for the tip. I never would have guessed my OCC may be the culprit here. In a few hours, I'll normalize the system by plugging back the original hoses and post my results here. I'll also do a negative terminal battery reset just for good measure. One more item on my data list that seems completely out of whack is my calculate load. It sits at 43 percent on idle! Normal should be 10.0 to 16.5 % according to the service manual. Did you also have this issue and was it also resolved by the OCC delete?

2013FSport

iTrader: (2)

If you have induced a vacuum leak allowing ^^unmetered air ^^ into the engine, this could make it think the load is high as the system is partially looking at vacuum to determine the load.

At idle and coasting are the higher vacuums... Unless you have a leak. So I'd say there is a good chance these are related. That said, you need to look this over and make sure that there are no loose fittings, cracked hoses, something disconnected.
And no, I'm not saying calculated load is solely based on vacuum.

rbipu

Finally some good news.. removing the OCC has had a positive effect. I am now within +/-3% on my short fuel trims on both banks. Again, thanks for the tip Aathon, very much appreciated. I will continue observing the long term trims and will make a final update here in a day or two.

The calculate load is still high. MAF reading with ignition ON (engine not running) is 0.59 g/sec. IS250 service manual says MAF should be replaced if reading is higher than 0.36 g/sec. So will replace and see what happens.

I inspected the OCC and it's collected a significant amount of blowby with barely 1500 miles since the last drain. Before I fitted the OCC about two years ago, the car would intermittently idle rough and would generate rough idle DTC's. Ever since I installed the OCC and a little bit of Italian tuneup shortly thereafter, I haven't had any issues with rough idling. With that said, I think I will retain my OCC and see if i could get it to play nice with my engine.

Thanks everyone!

Moisture

Try cleaning your throttle body.

IS250DIYER

You are welcome. I am a self taught mechanic since I was 7. I don't know everything and I'm still learning new things everyday but I know a thing or two about the 2is. I have done thing thing from oil change to tranny swap in my driveway.
when i had mine in, its like u dont see or can tell that the car isnt happy unless you plug in a scanner. It drove fine and sounded ok. After I replace the hoses to normal I could tell a bit of a difference on how well the car performed and the gas mileage.
Every two thousand miles or so I would get about as much oil in the catch can has you have there in the picture. I would drain it about twice every oil change at 3000 miles or sooner. I use Mobil 1 5w 30 and I never use oil additives only fuel additives. Like I said before I have played around with different lengths and diameters of hoses from the intake to the oil catch can along with two inlets into Outlets the oil catch can and the intake. I also did one Inlet but then split the hose into two different hoses in to two different spots on the intake.
Ive messed around with different o2 sensors from other toyota and lexus cars. Different MAF sensors and different brands/ lenghts of air intake tubes. I have a cheap eBay catch can and to me I think it's not the greatest by far. next time I get one I'm going to get a name brand high quality with two inlets and two outlets... i dont always check spelling and i use speech text from my phone to post so sometimes the sentences sound funny or there's a word in them that's not supposed to be there.
Aathon H.