how my small issue turned to big one

[BlueStreak]

Here we go: MZR DISI Ringland Failures

[MajesticBlueNTO]

Originally Posted by Lex Is this exactly how the piston came out of the block with the top ring oriented like that or was it moved? Also under what circumstances did this blow? Don't rotate the rings when you pull it out and get pictures exactly as the pistons come out of the block if you can as these will show where the ring gaps are. The next step is to measure the rings gaps.

the history of the motor is here

i wasn't there when the engine was disassembled and the engine builder may not remember as it was taken apart 2 months ago; however, given how meticulous they are, there is a high chance that the rings were not moved when removed, measured and when that pic was taken.

as for measured ring end gaps, the top one was 0.011" which, in their experience, is nowhere near enough.

[mrQQ]

hm, if there is popping in the exhaust when free revving, does it mean its running rich or lean?

[mrQQ]

anyone?

[BlueStreak]

Rich.

You have an AP, right? You can see the rich condition happen if you monitor AFRs.

[mrQQ]

Yea, I do have it, but I expect the rich to be due to faulty o2 sensor. WB is showing 1.0000 lambda, NB is giving 0.8v reading.

that, or there is some magic in how my leaky 3rd cylinder mixes exhaust gasses so that it's tricking the WB into believing it's stoich while in fact it's rich...

[mrQQ]

here is a log of idle and revving, there is definitely something strange about afrs, after pedal plip they turn rich, then after letting off they turn to infinity, which is normal, but then come down pretty slowly, and get into rich for a bit again..

[BlueStreak]

So you're trying to figure out if the O2 sensor is faulty? What end are you trying to achieve?

At this point, I wouldn't zero in too much on the data feedback until you take care of the hardware issues. Its a huge crap shoot at this point.

[Dano]

seems I remember mine doing something like that...if you are still recircing your VC vent into your TIP/Intake you could very well be spraying oil onto your maf like I did. I pulled my filter and the entire intake was covered in a mist of oil due to all the blowby.

I VTAed my VC vent for a day and the little filter was soaked through and dripping..in only about 20 miles.

I then connected an OCC to the VC and vented the other side which is what I am still running.

it was after all of this that I determined my cylinder was gone.

[mrQQ]

Originally Posted by BlueStreak So you're trying to figure out if the O2 sensor is faulty? What end are you trying to achieve? At this point, I wouldn't zero in too much on the data feedback until you take care of the hardware issues. Its a huge crap shoot at this point.

yea, just trying to see if they are ok..

Originally Posted by Dano seems I remember mine doing something like that...if you are still recircing your VC vent into your TIP/Intake you could very well be spraying oil onto your maf like I did. I pulled my filter and the entire intake was covered in a mist of oil due to all the blowby. I VTAed my VC vent for a day and the little filter was soaked through and dripping..in only about 20 miles. I then connected an OCC to the VC and vented the other side which is what I am still running. it was after all of this that I determined my cylinder was gone.

hm, strangely, my intake is clean..

[Dano]

How much boost do you run? I was running 26 which probably exaggerated the blowby. Lol.


Tappin

[mrQQ]

Don't run boost anymore at all, just stay out of it.

I just don't see what can cause different readings from o2 sensors except for one of them being faulty.

[Dano]

2nd O2 is there to calibrate the primary O2 so its hard to tell which one might be faulty...what is more likely is a crack in your DP/EM/Turbo causing fresh air to get sucked in and richen up the mixture unnecessarily.

I tuned a guy once that one day his AF was spot on and another it was lean as shit..13.xx on a 12.0 tune. after weeks of back and forth, I told him he had to have a leak in the exhaust somewhere...he "looked" but never found it so I suspended tuning until he would actually take his chit apart.

fast forward 2 months he e-mails me back and said the pulled the DP and a 1" crack had developed and expanded...probably grew from the initial leak I discovered during the tuning process which he couldn't visually see.

not saying that is your issues but O2s typically don't fail too often in my experience.

if you had a local's that you could borrow I'd say its easier than inspecting for leaks but if not, ~$300 is a lot to spend on a hunch.

are there any other speeds in your part of the world?

[mrQQ]

have both o2s in a bag to try, if they are fine i can return 'em.

no leaks anywhere to be found.

i've asked VersaTuner guy to add second o2 output, it's 0.7-0.8v while ecu says 1.0000 lambda.. somethings fishy...