Visit me at: http://www.ericthecarguy.com/ O2 Sensor Video: https://www.youtube.com/watch?v=NIzcztO-CCs Discussion about this video: http://www.ericthecarguy…
P0420 How To Diagnose A Bad Catalytic Converter -EricTheCarGuy
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Eric, I think you’ve over simplified what cat converter actually do. Old
two-way cats didn’t even do a thing to NOx emissions. Nowdays caltalytic
converters are a “three-way” type because they perform 3 functions:
-Burn unburned fuel (hydrocarbons) to CO2 and H2O (consumes oxygen)
-Burn CO to CO2 (again consumes oxygen)
-Reduce NOx to N and O2 (releases oxygen)
O2 sensors are used to keep the correct ratio of oxygen in exhaust to keep
all those 3 reaction going.
hey erice im a u.s i.g and i came home from AT and got an 2001 audi a6 it
got 95k on it and it and temp started to go up a little on it and then it
would start to misfiring on bank 2 ( cyc 4,5,6 )so i replace all sparks
pugs and wire but still have the problem so i take it to pep boys and they
said my cat’s r bad r they right i did get a o2 sensor code it was sensor 2
bank 2
sure looks like a better way to diagnose instead of drilling holes like
scotty
$1800 for my catalytic converter….hoping by watching this i dont have to
change it!!!
Failed Smog check in CA due to P0420 code…My O2 sensors performed like
the Subaru in the vid, BUT passed emissions with flying colors. They
recommended I replace the CAT CONV. BUT could it be the sensors giving the
bad readings? and NOT the CAT CONV since the emissions passed.
I removed 4 cats of my car , helps in power sound but you sure gonna smell
it lmao
I can’t stop watching your vidoes! AAARGH! :p
Published on the day the world was supposed to end. lol
I would be more worried about your diesel rod knocks than the converters
right about now. You have any oil in that thing, lol?
HMM! “NOx” is about the perfect name for it, because… its effects can
be… well… (waaiiit for it…)
NOXIOUS! 🙂
Ba-dump-TUHHHM!
eric,
thx for sharing man. your vids are very informative and its wonderful that
youre volunteering your hard earned time to allow others to save money and
DIY:)
idk about your subaru but i do know atleast in the older vehicles that you
can obtain an eastern brand converter for about 50 ( my volvo 240 is around
39 give or take) universal. how good are the eastern ones though at that
price id think shit but fill me in on this because if they are any
reputable quality ill just replace my original instead of welding the spots
that are leaking on the body.
in texas our emissions inspections for cars 96 and new basically consists
of plugging in a connector to the obdll port haha
what problems does a bad catalytic converter cause when driving.
Eric, I gots a audi A4 B5 1.8T Q.. currently having P0420.. So im digging
into this Catalyc stuff here.. So you are saying cats run around 1200F..
BUT non of your vehicles are not even close? I had disconnect in
understanding , should the catalic on your oddesy. be up there around a
1000F?
How can you tell if your catalatic converter is bad on a older vehicale
that you cant use a dianostic tester
And my precat killed my Qr25de engine
ha, so pre 96 you can actually just get rid of the converter because it
doesn’t have a DS sensor therefore. by removing the cat you’ll be saving
the planet more because you’ll be refuelling less than half as often. cats
just put strain on your engines, which leads to spending $.
how about the correct voltage on the 93 to 95 vehicles with a single heated
O2 sensor? such as the TBI GM trucks for example? do you have info or vid
on these? thanks
I had a cat come apart on 2008 Toyota Hilux using E10 Fuel. It blocked
flow and set an engine check light. Toyota wanted $3508 for cat plus
labour and freight. I took it up the road and had Beaudesert Exhaust fit
and after market one. Twice the size and number of cells for $350 fully
fitted. After 50klms of driving the check engine light reset. I now have
a scanner. My advice is shop around. Later had a 2 and inch sports system
and extractors fitted as well as kn and I made a cold air intake. Power is
up 15 rear wheel kilowatts and torque has improved too. Tows great now.
Stainless mandrel bent and heat coated extractors. Now to fit lpg.
God bless the americans who arent from california.
Even 3 way catalysts don’t touch Nox. Nox is controled mostly by EGR. EGR
lowers combustion chamber temperature below 1400 degrees F, limiting the
production of Nox….
i have a ford ranger 2008 3.0L D. car was running bad, i cleaning my
catalytic converter with a garden hose placed it back on truck runs fine
again.
So what if I’ve got the P0420, my primary 02 is reading high (mostly .75
range, but ocassionally dipping down to the .1 or .2 range…definitely not
as fast as it is in the video) and my secondary is holding steady around
.65V? Can I know anything about the cat in such an instance?
Before spending big bucks to try to pass the emissions test try some oven
cleaner! The part to clean is the hot wire in the MAF sensor. When dust
burns onto the wire the engine will run lean because the dirt insulates the
hot wire from the airflow. Running lean gives a higher burn temperature and
more oxides of nitrogen.
We don’t have any of those emissions tests in my part of TN either. They
used to in Nashville (Central TN) but not sure if they still do. At any
rate, I am still glad the car I am restoring does not have any of that
nonsense on it. The vapor recovery system is enough to fool with. I do
plan to monitor my EGT at cyl. 1 and 8, along with cylinder head temp but
not sure if the Edelbrock heads I’ll be using allow the latter to be done
easily.
Could a leak in the air intake cause the computer and 02 sensors to be
confused and throw a P0420 code to pop on? I replaced my cat and 02 sensor
and about 3 months after the 420 code popped on and I know it’s not bad as
it’s still almost brand new. Should I have my intake smoked?
I have a good question here….I have a 2005 Kia spectra. I put “Megan
Racing Headers” on it, a new cat, new 02 sensors and a full tune up. My
check engine light came back on. And I believe its because there’s no cat
between the 02 sensors now. So how far behind the cat does the 02 sensor
need to be for the 2nd 02 sensor to read the right temp???? Thanks for any
help.
I’m getting a P0420. My upstream O2 sensor is reading high. It’s averaging
0.8V. Why is this?
I am not sure where you are in Ohio but I am in NE Ohio and we still have
emissions testing its free now but you still have to have your cat tested
and HAVE to pass or you don’t drive it just had throw that out there
So with the temp method a good cat will read 100-200 degrees lower at inlet
vs outlet?
great video and very helpful.the tempt method saves doing the back pressure
method.
Eric the coke head
I think you might be diagnosing hydrocabons … i thought nox was when u
got 2 much air in your fuel mixture (running lean) and the temp was around
2000 f. ?
Excellent video, very informative, thanks.
Wow lol this just came up on my car too
You can also test vacuum to see if converter is clogged…
Hey Eric, i have a 1990 Lincoln town car with the 5.0 V8 and i wanted to
make it a fun drag/street car so my question is since it is a 1990 and OBD1
am i required to have a catalytic converter on it or can i just run
straight pipes all the way back?
I miss using 5 gas analyzer eric it was to me a sure way to see whats
wrong.
hi, if the cat is good, should the 2nd o2 sensor hold approx the same
voltage regardless of engine revs? Or is it normal to move up and down with
different engine revs, but hold a steady voltage when the revs are held
steady? Thanks.
Very informative Eric. I learned something today. Now I can go home and
have a beer!
Cut it off plant a tree
Infra-red temp comparisons are very reliable diag tools however scanner
live data is also good indication but not 100%. The communication bit/rates
of scanners and vehicle processors vary so you could mistake slow comm
speed for a lazy O2 sensor. The best and most accurate way to diag a cat/O2
sensors is with an O-scope.
So basically on working cat, temps should be higher on exit side of the
catalytic converter?