Car repairs

Car repairs. Any advice?
My acura is getting old…275000 miles so its understandable if it needs a bit of this and a bit of that.
current list of woes include an aircon that works only until it gets hot, then it stops…

And for about 4 years now the check engine light has been on for a P0420 cat low efficiency light. But the car has been driving fine except I need to clear the codes and then drive around until the sensors get active and quickly get the car smogged . Cars five years and older need a smog test every 2 years here in cAlif.

SO i’ve done that for the last two smog checks and the car has passed so the nox cant be that bad. It would’nt have passed if the NOX was bad. But recently sprung another code which means the knock sensor is on the blink so I found that was quite cheap to buy like 50 bucks or so and hope my mechanic next door at the gas station wont charge me too much to put that in. IF i could reach it I can do it easily.

no knock sensor means have to use Premium and there is a smell of gas meaning probably too rich a mixture.

So been doing a bit of reading up on ox sensors and all that trying to make sure its not my ox sensors acting up. Basically trying to avoid having to change the cat.
We cant order non calif cats in calif. And calif cats are like 1500 dollars while cats for other states (which is good enough to stop the check engine light) runs maybe 600. I am hatching a plan to drive the car to reno and have the cat replaced there !! It will pass smog here in calif ! I can also find some shade tree mechanic here that will charge that to install a non calif cat in calif, which i guess may not be totally legit, but better than running a straight pipe which is totally not legit.

straight pipe wont kill the check engine light though.
So in my readings and attempt to make sure its not the ox sensors and it really is my cat…im not sure what im seeing on the code reader is good or what?

I understand the ox sensor fuel ratio should flux a lot for sensor 1 prior to cat and be steady at as close to 0.45 as possible on ox sensor 2 which is after the cat??

Mine seems to do that, so assuming the ox sensors are ok? Which means perhaps the cat really is bad?

OR, I finally decided to replace the plastic cover for the air filter. There is a small nozzle that connects to a hose that connects to the top part of the engine. While most of the air intake goes to another part of the engine. NOt sure what this nozzle does , why does air need to be supplied to the top of the pistons?? Any mechanics? Well basically this has been broken for years. I thought nothing of it, but air apparently has been leaking into the top part of the engine, which i thought nothing of as its an air intake anyway right? And i guess its sealed to prevent stuff other than air coming into the top part of the engine?
But thinking maybe that has something to do with check engine light i ordered a new part. 113 dollars later at the acura store. it comes in a few days, I wil install it and see if it makes the p0420 light go away? will be great if it does !! I think the knock sensor probably is bad though as i have had driveability issues recently. Which the p0420 condition did not result in.

any mechanics want to explain what is what to a person who really shouldnt be repairing his own car but wants to save DINERO.

I’m sure @Ducked can explain to you how to use your refrigerator compressor, an old battery charger, plus a few paper clips to build your own CA-standard cat.

Reno is the cultural capital of the American west, so that’s an excellent plan regardless of cat or no cat. Did you know Reno’s home to the second and fifth best Sonic Burgers in all of the US?


To late to save Dinero.

If you wanted to do that, you shouldn’t have got such a newfangled car.

I’ve never had a catalytic converter-equipped car, and would like to keep it that way for as long as possible, though time inevitably runs out, and each time I go for a drive I’m spinning the chambers on the bullet with its name on it.

Your pipe sounds like a crankcase breather hose, but if that’s what it is, its a bit hard to believe you paid over 100US, even at Accura prices. Any bit of hose that doesn’t collapse under vacuum or dissolve in oily fumes would do. If you want something specially automotive go to a scrap yard (assuming they have them in California) and pull one off (assuming they allow that in California). You might even find an Accura one.

If it was bust and creating a vacuum leak (in which case it probably isn’t a crankcase breather hose) the system will attempt to compensate by adding fuel trim (I believe an OBDII scanner will give you fuel trim data, though I got no use for or experience with OBDII scanners)

IF its creating a vacuum leak short term you could just plug it (chewing gum, golf tee, chopstick, hypodermic syringe needle sleeve, etc) and see what happens, or doesn’t.
Long term not having crankcase breather might get your oil dirty or pressurise the crankcase, maybe blowing seals.

You can sometimes find vacuum leaks by blowing butane over the pipework. As the fuel gas gets drawn in the engine note changes. Smoke machines are also used.

I had an un-findable vacuum leak on my 1986 car which I fixed (so far) by plugging ALL the pollution control hoses (which I didn’t understand) and painting multiple coats of sunflower oil over the carb and intake manifold.

Modern-ish crankcase ventilation systems like I don’t have have a PCV valve which can stick. Another popular technologically assisted way of fucking things up is the EGR system and its associated valve, which can get clogged.

Old brake fluid is a good cleaner, but watch out for it draining back and hydro-locking a cylinder. Almost did that on a Honda Accord I was working on a few months ago and if I hadn’t at the last minute decided to pull the plugs I would probably have bust it when starting.

Lots of stuff on the Internyet, but maybe not here. This tends to be the unfunny-clowns-who know-fuck-all-about-cars-and-couldn’t-care-less forum, and I dont know much about the newer stuff.


Lol you’re right of course my1986 tellstar
Had no fuel injection I didn’t have any fancy gizmos had a carburetor it has no catalytic converter or even airbags so there’s no check airbag light come on No cat light coming on I don’t think it even has a check engine light

Those were the good ol days and those cars just ran and ran

The thing I am replacing is part of the airbox it is the top part of the airbox which contains the air cleaner element inside and the airbox has a big rubber tube which is where most of the air goes into the engine but there’s a smaller tube that goes into the top part of the cylinders which I guess is I don’t even know what you call it

But there is a mass airflow sensor that detects how much air is supposed to go from the air filter to the engine and this little hose that goes straight into the top of the engine is letting in air that is not being measured by the mass airflow sensor

And therefore causing the engine to not know how much air is coming in and therefore it is not able to measure the correct amount of fuel and therefore it’s not working properly and probably is a good reason why the check engine light is on

I used the OBD two sensor and I looked on the Internet to see how the bloody thing works and apparently according to the voltage reading my cat is healthy

That is to say the O2 sensor number one the one that’s before the cat is reading correctly between 0.1 to 0.9 V and going up and down up and down in a nice wave

Well the O2 sensor number two the one that’s after the cat is holding steady at 0.65 and it’s pretty much a steady line while the O2 sensor number one is going up and down up and down as the engine runs lean and how do you say the other one that’s not then and therefore up and down up and down like it supposed to

Yeah that’s it alternating between lean and rich lean and rich like it’s supposed to

So hopefully the cat will not read a fault after I put the new airbox in and there’s no leakage of air into the engine that’s not being measured by the mass airflow sensor at least that’s what I’m hoping

Hoping I don’t have to replace a cat

I suspect I probably will still have the engine knock sensor problem which is apparently relatively inexpensive should cost me about 50 bucks for the part and maybe 100 or so for the mechanic to put it in

Supposedly he won’t have to remove the intake manifold and can access it from under the engine

That will be saving labor costs
well wish me luck that’s what I’m trying to achieve by not having errant air hopefully the cat is fine and then it’s just a minor repair for the knock sensor

To be picky, because you have to be picky with this stuff to have any hope of making sense, your explanation, insofar as it is an explanation, does not appear to make sense.

IF the MAF measured air going “ from the air filter to the engine”, (“supposed to go” is meaningless. It measures reality, not intention ) and air was leaking through your “little hose”, it would be leaking upstream of the MAF and would get measured, so it wouldn’t be a problem, apart from dirt ingress.

IF however the MAF is upstream of the air filter, then such a leak would be un-metered air, causing lean running.

Leakage the other way into “ the top of the engine” which MAY be your concern , is unlikely to be relevant because the air won’t generally be going that way (you could check with some smoke) and more importantly because that’s probably the valve cover, connected to the crankcase, (hence crankcase breather) not part of the induction path, so it wont directly affect combustion.

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So the crankcase is pushing air out and not sucking in ?
If that is the case that makes kinda sense as the tube will then be transporting air back into the box before the MAF

Like I said, if it was “transporting air back into the box before the MAF” then it wouldn’t be a problem, since the MAF would meter that air, (unless it was such a big leak that the system couldn’t adjust for it.)

Depends where your MAF is.

I dunno. Its not my MAF.

I don’t have a MAF. Don’t much want one either.

From a design point of view though, IF your little hose is a crankcase breather hose, the Honda honchos might want it downstream of the MAF, since otherwise it might get the MAF dirty, causing rough running and unbearable shame.

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Doesn’t seem to be a breather because there is zero oil residue on an 18 year old car

Leads me to think it sucks some air into the engine but perhaps not enough to be an issue as long as it was sealed from the outside air

But since it’s not sealed there is no vacuum effect however small

This is all happening upstream of the MAF

At any rate soon as I put that new box lid on I will clear the codes and see

Will be disappointing if it has zero effect

Still thinking it’s worth it to get a good seal there
Although it has been like that for so many years I’ve forgotten

The cover and the little tube

The new cover versus the old
Notice the broken piece ?

The inside of the broken cover
Not sure why it needs the box inside

Have cleared the codes
Gonna drive it now and see what happens
Will the p0420 cat low efficiency come back?
Will the knock sensor fail light come back

Keeping fingers crossed

Obd2 reading at idle and at 2000rpm
Not sure if cat is working well seems so at idle but at speed maybe not
Let’s see if the p0420 comes back on later
So far not

But the knock sensor is for sure kaput
Because that indicator came back on fast

Got a new knock sensor at oreillys for 63
Including tax snd my mechanic at the chevron station is installing it for 120
Easy 120 all he has to do is put it on the lift reach under and unscrew the old one and screw in the new and attach the connector

But hey if I had my own garage with a lift
And all the tools I would charge me 120 too
Funny enough the sensor is made in Taiwan

The air cleaner lid was made in Japan equally surprising thought it would be made in China as so many car parts are now

Hey if spending 113 for a lid fixes my p0420 I would be happy as that is a lot cheaper than changing the cat which costs something like 600 for non calif cat and maybe as much as 1800 for calif cat and that doesn’t include the labor to put it in which may be 200 to 300 I’m guessing

And when the new knock sensor works I can go back to using regular gas for 40 cents a gallon less

I have been using premium because the knock sensor was whacked

There goes the budget for this months overnighter excursion somewhere in calif

Well 24 miles of driving after new knock sensor put in and so far no codes
Hoping the new lid some how fixed the p0420 code
Found that the little tube also had two smaller tubes that lead somewhere else into the engine

So if the code doesn’t come back it would mean the lid fixed it
And I should have done it four years ago so as not to have stared at that check engine light for so long

Sometimes I don’t do anything unless I have to
When other issues started popping up is when I have to deal with an old issue
Now to tackle the airbag light which has been on fir years as well

Apparently taking the buckle apart and checking if it’s sticking could be the solution

After which I need to reset the airbag

And then to tackle the aircon problem which needs an aircon specialist with specialist equipment

I still have this weird recent issue where the car dies
and needs to be restarted after the auto choke goes off after the engine warms up

But the rest of the day it’s fine
Can’t put a finger in the problem

Where is the better of the two?
I will try it next time I’m in Reno

Be cautious if fiddling with airbags. I hear those things can just jump out at you.

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Yes I am thinking maybe I should not mess with those as if it goes off and my head is in the wrong position I could be killed

Not worth it

Besides the airbags are over 18 years old probably better they are deactivated anyways
And they could be the dangerous Takata airbags too

This way with the light on the system is deactivated
So I hear

Is @sulavaca still around, I wonder


We do miss his expertise around here !!