Honda failing smog test

Maintenance/Repairs
1

Hi All :slight_smile: !

I’m troubleshooting failed emissions smog test (emission result numbers, most-likely causes & solutions on how to pass on next smog
-test). N I would REALLY appreciate some help & info. on how to help Old-Faithful pass emissions in California ! (SIDEBAR: I’m a female-teacher w/ a $-black-out month this summer, & the purchase of a new car before 2019 is NOT my first preference… BTW, MOST TEACHERS AREN’T $-RICH! lol. SO, I STILL NEED MY OLD-HONDA to live!)… Thanks! So, HERE IT GOOOES:

Old Faithful’s Issues/My Wonderings:

Failed-
Possible causes of 111 HC (PPM) &
high 796 NO (PPM) measured @ 15 mph.

Passed-
CO (%) .68 @ 15mph

Why would ALL emissions measured at 25mph pass, when 2/3 of emissions tested @ 15mph failed (HC & NO failed, CO passed @ 15mph). PLEASE, EXCUSE MY REDUNDANCY; I’d rather NOT be UNclear.

Other observations /wonderings/ thoughts that might help us all troubleshoot:

Exhaust surrounding area on my, once, “white” Honda (i.e.right bumper & r. exterior trunk) has now been usually coated with an apparent layer of BLACK-EXHAUST/soot. SO, that area of the car’s body has morphed into a “gloomy-gray” -LOL.

Some time ago, I’ve sometimes noticed a RIDICULOUS (lol) WHITE-colossal cloud of smoke emitting from exhaust pipe, soon after turning on /driving-off in the morning/after a 6 to 8 hour day. (White cloud = RED-face).

Prior to failed smog test this month, my '92 Accord had passed smog every single year -prior to me replacing/fixing one of the cylinders (nearly 2 years ago). I WONDER if this may have been a contributing culprit/factor to my car failing smog test 2 years later.

WHY does RPM vary from one FAILED smog test to another, if the mph doesn’t vary??

Related Spec’s:
1st VIR shows…
15mph, 1712 Rmp
Vs.
2nd VIR shows…
15mph, 1670
Also,
1st VIR shows…
25mph, 1746 RPM
vs.
2nd VIR shows…
25mph, 1789 RPM

Also, PCV valve was replaced after the 1st FAILED 2018 emissions test because my carrito decided to shake-shake-shake (aka surg).
Fixed the surging prob., but still failed emissions, on the second smog-check attempt… ARG.

Based on all of the above, WHICH OF THE FOLLOWING SEEMS TO BE A MORE PROBABLE CAUSE/CAUSES FOR MY 1992 HONDA ACCORD EX’S FAILED EMISSIONS SMOG TEST:

CAT
EGR
O2-SENSOR
ALL/NON/SOME OF THE ABOVE
ETC.

PLEASE, HELP, I WOULD APPRECIATE YOUR ASSISTANCE, HELPFUL C.T.-PEEPS! GOD BLESS!

Thanks!

2

You might need a new car sooner than you think. Its burning oil! Have you checked the oil level recently? You need a compression test to check all 4 cylinders on this car.

1 Like
3

What do you mean by that statement?

Tester

4

I’m thinking you might need a catalytic converter

As for the variance in engine speed, during the dyno part of the smog test, the inspector is driving the car on the rollers and at the same time watching the smog machine’s screen, making sure the vehicle speed and engine speed are within the allowable parameters. No 2 smog tests will be the same, meaning the engine speeds might show slight variations.

If you choose to have the catalytic converter diagnosed and replaced, just go to a reputable independent exhaust shop and have them weld in a part which is legal for california. Believe it or not, some unscrupulous and/or misinformed guys will weld in a part which isn’t permitted. If the inspector sees an aftermarket catalytic converter, he’s supposed to check if the part number is approved for that particular vehicle. If it’s not, you fail the test, no matter how clean the tailpipe emissions were

5

I am also intrigued by that statement.
Could the OP tell us exactly what “replacing/fixing one of the cylinders” means?
:thinking:

6

Based the n the symptoms you describe, it could be one of many things, each of which would involve a costly repair, so let’s start with low cost items.

  1. You might just need a tuneup, new spark plugs and spark plug wires, and maybe a new rotor/distributor.

  2. Your valves might be out of adjustment or damaged, but just checking them is going to be costly.

  3. Worst of all, since you seem to be burning oil, you might need an engine rebuild (new rings in the pistons).

I agree teachers are underpaid, but it’s time to face the reality that this car is doomed for the scrap heap or remaining life in a state that doesn’t do emissions testing.

2 Likes
7

Thank you very much for the detailed reply!!

8

Thank you very much for your time & help, COROLLAGUY1! -God bless!

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2 years ago this is what my mechanic fixed & what I meant by the above statement… I hope this gives more clarity… Thanks!

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12

N furthermore… I hope this helps, too… :blush:

13

Do you think that using Cataclean might help to pass the smog emissions test this time?

14

I battle Calif smog every two years with my early 90’s Corolla. You might want to read through this thread for some ideas on the HC component of your problem. Assuming theres no major mechanical problems with the engine and all the routine engine service is up to date, the nitrogen component suggests your cat may be due for replacement.

15

Did the timing belt break at one time and that is what led to the intake valve and cylinder head work and are you confusing this with the “fixing the cylinder” comment?

The black on the bumper is likely due to a rich running condition or oil burning. Should it be asked how often if ever you check the motor oil level in the engine and whether or not it’s consuming oil?

If it’s burning oil then nothing is going to help you short of major engine work.

16

What’s the limit on HC at that mph? 111 doesn’t seem like it would be much over the limit. ON my corolla the limit is 130 at the speed it sometimes has trouble with. If 111 isn’t much over, then it shouldn’t be overly difficult to remedy that part of the problem. The 800 NO, that may be another story. I’m expecting that is probably quite a bit higher than the limit.