Car repairs

Yeh, sort of. Without a breather the crankcase is pressurized by blow by gases (not really “air” though it might be similar to the “air” in South Kaohsiung in the winter) that pass the piston rings into the sump, which is why there is a crankcase breather system that sucks from the engine intake.

However, some systems have more than one breather, so its conceivable that if one of them was bust, the other one would suck actual air back through the break into the crankcase and hence into the engine.

Sometimes one of the systems is designed to operate at WOT when there isn’t hardly any intake manifold vacuum behind the throttle plate because the throttle is wide open, hence WOT.

Taking a wide open guess, I’d say your pipe might be such a pathway, and isn’t oily because its been bust for ages, and you don’t use WOT very often. The wee plastic box thingy might contain oil collection baffles, which might work.

Or not. All a bit complicated for me.

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Sounds maybe consistent with lean running, which would be consistent with an air leak. What do your fuel trims look like?

Well keeping fingers crossed
the dang check engine light stays off

Let me plug in the tool
What should I be looking for ? Short term fuel trim and long term fuel trim ?

Could be since my engine is a vtec engine snd I rarely push it past 3000 rpm

Well, like I said, this is all a bit Kraftwerk for me, but I vaguely think you are looking for big numbers, which indicate the system is dumping compensating fuel in.

In detail I found it a bit hard to get my head around when I looked into it, but I wasn’t very motivated.

Dont have time to search out sources right now (grading deadline looms) but you could look into South Main Auto and Pine Hollow Diagnostics on that there Ootoob that you young fellers prefer to the written wurd (which is worth a thousand pictures)

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well after about sixty miles of driving the check engine light came back on !! P0420 ! The cat must actually be bad. Well at least it takes a long time the light to come back on. Previously after a reset it would come back on pretty fast so I had to rush and get the smog check done. Because although the nox levels are low enough to pass, if the light is on you automatically fail.
Now i have more time from reset to smog check so at least the car should pass smog a few more times,

Bad thing is with the check engine lit for this one item, it wont be able to warn you if there are other items. LIke who knows how long I have been driving with the bad knock sensor? it couldnt warn me through the one check engine light because that was already lit for the p0420.

will put a graph of the fuel readings if you can make any sense of it.

I guess i have to bring myself to accept the fact that the cars sensors are pretty good. It picked up the bad knock sensor chances are pretty fair it knows the cat is bad , i just have to grin and bear it.

was wishful thinking a simple replacement air cleaner cover will cure the cat of its ills.

must be a “moon shadow”

Plus I hear there are a lot of cat houses in Reno, so he should be able to pick up a cat there for a decent price.

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with or without muffler?

Without…the louder the better!

Tommy, a few ideas:

  1. that hose going from valve cover into the airbox is a pollution reduction idea, whereby oil vapors are returned to the air intake rather than sprayed out onto the street. and the other couple of hoses are also part of the crankcase breather return, most likely.

  2. because the airbox was cracked upstream of the MAF, it’s not likely to be where your lean running is from. sure you don’t have any leaks downstream? Old hoses can split in places you just can’t see, and only show when the engine is pulling a lot.

  3. the box and baffles inside the airbox is likely there for controlling the resonance and may assist airflow at particular parts of the rev range. that’s pretty common: these things are carefully engineered for control of airflow and alsos inlet sound.

  4. Yes, you definitely should activate the VTEC every now and again. it will decoke your pistons, free up the lifters, give you generally cleaner and more fuel efficient running all round. Obviously not something you’d do all the time, but those engines need to rev to keep them happy

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That sounds like a good code for CA

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Oh, of course another thing is do you believe your MAF? they don’t last forever. there are some dodgy ways you can revive the sensor in them, with careful solvent cleaning, etc., but you would probably be better off with a new one that does work well.

You should probably check your MAF readout is calibrated, and Im not sure you can do that just with a code computer.

Don’t think my simple code reader has MAF data
But I did clean it a year ago with MAF cleaner

I may just have to resign myself to the fact that the cat is broken but I won’t replace it as long as I can keep clearing the code and it passes smog
The car is 18 years old and each smog check is 2 years so perhaps I won’t be keeping it beyond the next cycle because other issues may pop up due to the car being so old

Will try to sell to an enthusiast

Scotty Kilmer reckons you can wash them. IIRC he just used dumped the cat in a bucket with laundry detergent, but I daresay there are alternatives, (I[d be tempted to try old brake fluid, though AFAIK that isnt a recommended procedure)

Never done that, of course, but I’ve back flushed a non-cat system I thought might be blocked, by sticking a garden hose in the back with the front end disconnected.

Got some debris out.

Thinner in the petrol (see below) less plausible because it’ll mostly be burned

I think I will just go on seeing the check engine light
As long as I can get the car smogged and it passes
I don’t have the tools or the lift or the expertise to be taking off the cat to dip in hot water
Wish I did

Every now and then I will run a scan to see if any new issues pop up

Meantime I have revved the engine up to 6000 rpm s few times and ran on 4000 rpm for some distance
And I smelt this weird smell

But the car no longer just cuts off by going below 500 rpm when stopped
Rpm stays at 800 now
So something positive with the new knock sensor snd revving the thing up

It’s not smooth going past 4000 and makes a hecka. Noise probably because it’s not been there for so long

New engines tend to rev high pretty easily and not sound like the second coming

Don’t believe you.

If you “wished you did” you would make it so.

Tools are not that expensive and you are not in a rust belt state, so you wouldn’t generally need very good ones.

You probably don’t need a lift to get the cat off but in any case you could very likely do it in situ. To soak the cat you’d need a fill point higher than it, which implies either parking facing downhill or putting a fill hose in the tail pipe, sealed by a tight fit, inner tube, duct tape etc. You’d have to be careful not to flood your engine, though turning it over with the plugs out should clear it if you did.

Back flushing (not essential but might help) you would need spanners for the exhaust flange bolts to split the front and rear sections. I had no trouble doing this on a non-cat system and the basic geometry should be pretty much the same.

“Expertise”? Cmon. I might even trust a Taiwanese mechanic to fit an exhaust, in fact I have, though come to think on’t they did fuck it up pretty badly and I’ve only just recently managed to fix it.

Whether its worth it is another question. I’d say not while you can still sneak it through the test just after a reset, so you have something to lose. Once you can’t, and havn’t, it might be worth a try.

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It’s just my polite way of saying that’s ….when it’s martini time !

I has seen that dang light fir four years I can see it for another four

The power of patience ….and a tight pocket book

And a general avoidance of something that has become too much work

But hey progress
Has been made I did have a new knock sensor put in and revved the shit out of the engine so now the rpm doesn’t fall below 800 on idle and the car doesn’t stall anymore

But what is that funny smell I smell when I rev the shit out of it……shit probably

I better save up for a new cat ….in Reno

Because chances are more than fair the cat
Is F…ed

This may be what my cat is like inside already
There ain’t no saving it