can't pass emission test/94 accord, help appreciated

i have a 94 accord ex, 4dr. 2.2l engine. i'm having a hard time passing
the emissions test (houston, tx) and am hoping someone can help.

after failing the nox portion i had it analyzed and was told it's the
catalytic converter (which was replaced last year after failing, also
had the combustion chamber cleaned last year too). i got a second
option (dealership) who said the same thing. egr, etc is working fine.

since my current converter is a universal aftermarket part, the dealer
estimate was $1200 for a new one w/ proper connectors.

i went back to midas and had another after market converter put on.
unlike last year, this morning i failed the test again. i was told the
aftermarket part was cheaper for a reason... it isn't big enough to
take out the emissions for my car. oddly, the test results were exactly
the same before and after the converter was installed. i drove for
about 200 miles between the repair and the retest. it's like the
converter isn't taking anything at all out.

can anyone give any specifications for the honda converter and any
after market parts that are similar? i don't see why i'd have to pay
1200 for a honda converter when others are only $200. if i can find one
that works, i'd rather replace it every year. or is it really true that
only a honda converter will work? i'm only planning on keeping the car
for another year or two. i'd hate to put so much into it just for a
sticker on the windshield. i've now spent close to $800 over 2 years on
this. (yes, i see the irony... had i have just paid the 1200 last
year...)

any thoughts/comments would be greatly appreciated. thanks.
mark

 

does the engine burn any oil?
what kind of gas mileage you getting?
how many miles are on it?
have the O2 sensor(s)ever been changed?

case in point:

98 civic CX. 42257 miles
NO test results from 2003:
15mph: 113
25mph: 9

one year later, 2004, my primary O2 sensor went bad and left a MIL code.
replaced it.

NO test results from 2005 (yesterday):
98 civic CX. 48601 miles
15mph: 8
25mph: 11

just replacing the sensor before the catalyst dropped the NO levels from
113 to 8!!! max allowed is 477 at 15mph, and average is 57.

 

are your NO results the same as what's listed as NOx on mine?

engine doesn't burn any oil... at least not enough for me to notice.
get it changed regularly and levels aren't low. last time i checked, i
got about 25mpg. mixed city/highway but lots of traffic in houston.
50-60 miles/day. car has ~165k miles.
i doubt the sensors have been changed. i've never done it and don't
remember it being done.

what type of test do you have done? since mine is older than 95, i have
to get the asm test vs the odbii test. my test results show they test
for hcc, co, co2, o2, nox, and dillution.
allowed nox(ppm) here are 910@25mph, and 1006@15mph

my readings are almost double.

how much does it cost to get the sensor replaced? is it something i can
do? wonder why no one's mentioned it so far. both analysis places said
everything's fine and must be the converter. they said there weren't
any codes present. could it be bad and not register a code?

the sensor isn't on the form they gave me for potential high nox
readings. it lists:
air injection system (don't think i have?)
egr system (tested fine)
combustion chamber (cleaned last year)

thanks! i'll call and see if they checked the sensor.

 

sorry if this sounds stupid. are these oem parts? i was quoted ~900 for
the converter. finding some online for far less. wondering if they're
the same generic stuff that midas put on that is failing or actual
replacement parts to match original.

http://www.expressautoparts.com/PartSearch/getpart.cfm?year=1994&make=HO&model=ACC-EX4-002&category=H&part=Catalytic%20Converter

http://www.autopartswarehouse.com/cats/models.php?make=honda&model=accord&year=1994

thanks

 

I see a part called 'converter' on the following website. These are OEM
parts:

www.hondaautomotiveparts.com

Click you model and info, and then go to Exhaust.

t

 

i believe so...

same here. the only ones with limits are obviously the pollutants... HC,
CO, and NO.

both tests were ASM, on a dynomometer.

here, its 764, and 477 for a 98 civic, 1.6l engine with california
emissions.

if its a 94, its pre-OBD2. the sensors could easily be bad and not cause
a code. after 165k miles, they likely are. and since you have a new cat
on there, id look at the sensors.

no idea why no one has mentioned it so far. im curious how the mechanics
know the sensors *arent* bad.

nope, dont think ya do.

 

Junk the Piece Of Shit Clunker and consider purchasing a REAL
automobile.

Especially in Texas where everything is prized big - you are a complete
idiot to go honda. You idiot jerk, get the **** off the road if you
intend on polluting the air.

 

wrote in

POST ALL YOUR NUMBERS. Post *your* results as well as the *limits*. And
include whether the numbers are ppm or percentage.

You may have other problems here, not just the cat.

High NOx can mean:
1) EGR malfunctioning
2) Incorrect fuel octane
3) Excessive combustion chamber deposits
4) Cooling system running too hot
5) Ignition timing too far advanced
6) Catalytic converter worn out or poisoned
7) O2 sensor running engine too lean
8) Air leak into intake leaning mixture out.

Without your numbers, we're in the dark.

Which specific test did you fail?

What's your gas mileage? Don't guess. Give real numbers.

 

hes already had one cat a year or so ago, now another with no change in
the numbers. BUT the original O2 sensors. aftermarket cats may not be
the best, but they should work *Somewhat*. no change in the NOx tells me
thats not the problem.

i am, however, not as knowlegeable in these things as you. and i know
this

 

------------------------------

Sounds like you're wrecking cats becasue you're not burning your gas
cleanly, or you're burning too much oil. Without knowing the mileage, my
first guesses are: You need the PCV changed (since it can allow a mess
of oil into the intake), or a complete tune-up, possibly including a
valve adjustment.

The cat is downstream from your problem. It ain't your problem, just the
indicator of a problem.

'Curly'

 

motsco, i completely agree with the logic but i've taken it to two
respectable places for analysis and both say everything's working
correctly and it's the cat. unfortunately i can't afford to continue to
second guess everyone who looks at it and get another analysis.
everyone keeps blaming the aftermarket cat and says it needs the honda
part for ~$1000. pretty sure i'm not burning oil. levels are never low
when i check.

tegger, here's all the numbers [standard/mine@25mph,
standard/mine@15mph]
hc(ppm):127/17, 132/22
co(%): .71/.03, .73/.04
co2(%): na/14.7, na/14.7
o2(%): na/.2, na/.2
nox(ppm): 910/1870, 1006/1767
dilution(%): >6.0/14.7, >6.0/14.7

i only faild the nox portion of the asm test.

i'll have to post in a week to give real mileage numbers. i reset the
odometer when i fill up and refuel every 350 miles. it's usually on
empty then but the light's not on. it's a 17gal tank. so i figure i
could go 400mi which = 23.5 mpg. i drive 30 miles each way in mixed
traffic. open highway in the burbs and standstill bumper to bumper
traffic in the city.

not sure how long it takes to build up combustion chamber deposits but
that was cleaned last year. analysis place assures me the egr is
working correctly and the ports aren't clogged.

hope the numbers help. thanks everyone for your help.

 

new question,
can bad spark plugs affect nox? i took it to a mechanic to do a general
tuneup and he said some (tips) were worn to virtually nothing. it
seemed to drive fine and mileage was good. engine light wasn't on.
going to do the retest tomorrow so i'll find out if it helped but i'm
wondering why no one else ever looked at them. guy said they were
probably in that condition for a couple years.

 

The computer in any car has several ways to set a code, open circuit, short
circuit, out of range and the expected numbers don't match up with the
expected numbers of another circuit.

So O2 sensors can work properly by all indicated numbers, but still be bad.
One o2 sensor we were just told of at a training class would hang up at a
high number, but only long enough to cause problems, but not long enough to
set a code, and it looked good on the lab scope when cold.
I just changed one today that set a code for slow response, but it wasn't
slow just the numbers weren't as high or as low as expected.

I don't think that the O2 sensors would set a high nox, but at this same
class he mentioned that cheap cat converters were cheap for a reason.

When I had a VW Bug in Phoenix, and had to do emissions, I'd take it to a
repair shop and let them know it was emissions were due. they would tune it
up with emissions in mind.

I would just take it to a reputable shop that knows emissions and has a 5
gas analyzer and let them fix the car.