Hi all,

I am new to join HT, although I've done a search and notice that RotaryBzzzz is the guy to talk to about this stuff, but anyways. I have an 88 Accord Lxi (no mods) 5spd. and failed the emissions test twice over CO%.

My numbers are as follows...

2nd trip to jiffy lube:

25/25 test

HC ppm - 44 (181 allowed) pass
CO% - 1.41 (1.16 allowed) fail
NO ppm - 146 (1313 allowed) pass
rpm - 2861 (3000 max)
CO+CO2 - 14.0 (6.0 min)

50/15 test

HC ppm - 13 (187 allowed) pass
CO% - 0.01 (1.05 allowed) pass
NO ppm - 693 (1438 allowed) pass
rpm - 1763 (3000 max)
CO+CO2 - 12.5 (6.0 min)


he took the old test, but the reading from that one (the first time i went in) the CO% was 2.21 (on 25/25 test). I did the following between the 1st and 2nd testing:

-changed plugs, wires, rotor & cap (honda dealer parts)
-removed air filter and resonator
-changed oil

it brought the CO% down considerably, but it still isn't enough. i was told that cleaning the EGR ports and TB would be the best bet. i will try that this weekend. to see if that helps.
can anyone think of anything else that could help it run less thick as it's doing?

Thanks for your help.

 

i put 100octane race gas just in case and passed

 

take out the intake hose and as the test is running, spray in a mist of water every few seconds into the intake, ur readings will be way low and ull pass

 

Your car is running pretty clean, especially at idle. Usually, emissions at idle are where older cars (with worn out cat convertors) tend to fail. 0.01 CO content at idle is super ******* clean.

[Edited]

My questions are these:

- Did your printout have O2 content as a seperate number? What are they?
- What are the total miles on the exhaust system & has the car ever had any exhaust work done? Like ever had a muffler slapped on then taken off?
- Is the exhaust (cat + post cat) still the stock OEM honda as built?

EDIT: I've pulled my own emissions sheets and here are my numbers as a baseline. My car is a stock runner (mods: K&N insert-filter + removed resonator, factory exhaust, 138k, 5spd). These numbers are for a California DYNO smog which is different than the typical revving test. Here in Cali they strap your car onto rollers and test emission output WITH A REAL-WORLD LOAD ON THE ENGINE (i.e. motor working to pull the car around). I've been told cars that will pass on a revving-test might not pass with this method and vice versa so understand my baseline dyno-test is derived differently than your rev @ idle-test. Use my numbers as a guide not a rule. (as a sidenote, my old 16v jetta passed beautifully when california switched to dyno-smog. I was "barely" passing with the revving-style test but had no problems with the dyno-test).


EMISSION TEST RESULTS - (removed K&N airfilter, removed reasonator, 91 octane pump gas, new 10-30w oil/ new spark plugs/ STP fuel injector cleaner in the tank)

15mph @ 1638 rpm
CO2%__%O2___HC______CO%___NO
15.0_____0.0___10_ppm__0.00____143_ppm

25mph @ 1751 rpm
15.1_____0.0___6_ppm___0.00____4_ppm

So you see I have 0% O2 saturation at both low and high speed testing...that's a good thing b/k no O2 means it's being converted into H20 + CO2 to kill CO + HC emmisions.


Modified by RotaryBzzzz at 4:59 AM 10/4/2003

 

you know, they just gave those numbers which i posted above, also the gas cap test (which passed)... one thing i can tell you is the car has 178k on it. i bought it in January from the original owner (and when i tested it back then, it passed emissions w/ ease)... i have (in recent months) put in the lowest grade octane (87). i believe all exhaust parts (cat, muff, etc.) are original stock. i did notice that the muffler had done some rusting through (the car came from Washington state) and at one time I had to pull off some of the rust that was dragging on the ground (although i don't think that a rusted muff contributed to it running rich)... after running the car awhile and being at stoplights there's a little smoke coming from what appears to be the tranny area (passenger side) is why i believe it could be clogged EGR ports, possibly throttle body.

i haven't tried fuel injector cleaner, and maybe that's what it needs. but no, no separate O2 readings, just the combination of CO+CO2... the following are the results of the test back in Jan. (i have no idea why it's gotten worse since then)

25/25 test

HC ppm - 46 (181 allowed) pass
CO% - 0.27 (1.16 allowed) pass
NO ppm - 428 (1313 allowed) pass
rpm - 2902 (3000 max)
CO+CO2 - 14.7 (6.0 min)

50/15 test

HC ppm - 26 (187 allowed) pass
CO% - 0.05 (1.05 allowed) pass
NO ppm - 386 (1438 allowed) pass
rpm - 2979 (3000 max)
CO+CO2 - 14.7 (6.0 min)


So as you can see, it improved in alot of areas with exception to the CO%... i don't know if i should mess with the idle or what. can you think of anything else?

thanks again for your help.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 88AccordLxi &raquo;</TD></TR><TR><TD CLASS="quote">after running the car awhile and being at stoplights there's a little smoke coming from what appears to be the tranny area (passenger side) is why i believe it could be clogged EGR ports, possibly throttle body.

</TD></TR></TABLE>
I've never seen EGR ports clog up on an 88 Accord. I doubt that is your problem because your NOx is well within spec. Your smoke is probably comming from an oil or coolant leak.

Since it failed on CO, I would concentrate on finding out why it is running rich. Checking the operation of the o2 and t/w sensors might be a good place to start.

 

I'm stating the obvious, but what I notice is that your CO+CO2 numbers are alot more divergent than your initial test. Notice in my readings, my CO2% is very tight between the low & high speed test.

I also notice you NOx 50/15 readings have almost doubled since your first.

From what I understand about OBD0 cars like your 88, the range that an O2 sensor can be out of spec is quite large. You might wonder why your checklight doesn't go on; perhaps it's right at the threshold of "going bad to the ecu" but not quite there yet.

...let me continue this later....

 

so RotaryBzzzz, would you think it a good idea to pull o2 sensor and maybe clean the sensor part of it with alcohol or some substance (maybe too much carbon build up?) and clean the TB and may make a difference? i really just don't wanna keep going back and forth to the emissions place.
would taking it somewhere else be any different? do you recommend any gas or oil treatments? i mean, i'm so close to passing it seems. no CEL's, .25 from pass..

thanks again for your help.

 

What kind of gas mileage have you been getting lately? Has it gone down since you've bought the car (for a similar style of driving)?

Unfortunately, you cannot really clean an O2 sensor. If its poisoned/failed, they're trash. I'm not sure how familiar you are with electric multimeters, but I would pull the sensor, measure the ohm resistance it throws then check it against what a manual says is in "spec". This is what chionovica is saying to do w/ the o2 + t/w sensors.

Even if you don't check them (+ while your car hasn't thrown any cels), some would call 172k on an O2 sensor getting "pretty long in the tooth". If the oil wasn't religiously changed throughout the cars life (does you engine idle almost silently? mine does), crap just starts coating everything. While I hate throwing crapshoot parts at cars, a new O2 sensor would not be out of line with that kind of mileage. You time is valuable....i would replace the sensor before I smogged it again. Cleaning the TB couldn't hurt either if your doing this all yourself...

Since your convertor seems to be within spec, that would be my first attack. I'm not sure what ppl recommend but I think for your year accord, you can get by w/ a non-OEM o2 sensor if the honda-part comes in really pricey.

 

Chiovnidca & RotaryBzzzz,

Thanks for your help. So you think I should replace o2 and thermostat/thermal fan switch sensors (i don't know the t/w abbrev.)... there is little smoke that comes from the pass. side of the car... but there is a burning smell, and it doesn't smell like oil. possibly need new coolant, therm. stuck open?

i'll try checking the sensors and let you know what i come up with.
TIA.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RotaryBzzzz &raquo;</TD></TR><TR><TD CLASS="quote">... but I would pull the sensor, measure the ohm resistance it throws then check it against what a manual says is in "spec"...</TD></TR></TABLE>Can you really test them like that? Tell me more...

I thought that when you're looking for 10 to 40 ohms, that's the heater, not the sensor itself. I always thought you have to use an oscilloscope or something to watch the sensor signal in operation. Sluggish & slow-oscillating when they're going bad. Since the sensor does it's thing by ion conduction thru a peice of ceramic, I imagine the sensor would measure open-circuit when it's cold.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">Can you really test them like that? Tell me more...

I thought that when you're looking for 10 to 40 ohms, that's the heater, not the sensor itself. I always thought you have to use an oscilloscope or something to watch the sensor signal in operation. Sluggish & slow-oscillating when they're going bad. Since the sensor does it's thing by ion conduction thru a peice of ceramic, I imagine the sensor would measure open-circuit when it's cold.
</TD></TR></TABLE>
A scope is the best way to check the operation of an o2 sensor, but a voltmeter is usually good enough. I don't think checking the resistance will do any good either. (Except the heater, like you said.)

 

i finally passed! thanks for your guys' help. i changed out both o2 sensors and reset the ECU and it passed with flying colors.

25/25 test

HC ppm - 23 (181 allowed) pass
CO% - 0.09 (1.16 allowed) pass
NO ppm - 278 (1313 allowed) pass
rpm - 2886 (3000 max)
CO+CO2 - 15.0 (6.0 min)

50/15 test

HC ppm - 16 (187 allowed) pass
CO% - 0.02 (1.05 allowed) pass
NO ppm - 595 (1438 allowed) pass
rpm - 1692 (3000 max)
CO+CO2 - 14.7 (6.0 min)

i noticed from my previous inspections that i lowered hydrocarbons and NO% readings considerably.

 

congrats! Ain't nuttin' better than seeing those 04' tags come in the mail...