New member and new Accord owner needs help.

[kojo96]

Hi all, nice forum here and seems to be LOTS of knowledgeable Honda owners. I recently acquired a 1989 Accord (carb) with a 5spd, very clean with 220k miles, runs great and everything works!!! Problem I’m having is passing CA smog. I’ve been lurking around the forum for the past few days reading LOTS and applying what you all have posted and have gotten reasonable results. Below are the 2 test results and what I have done to try and improve the numbers. Listed first are the test results from last test that passed from last owner: btw, I pass everything but NOX.

Last owner: CO2 O2 HC CO NO
15mph 14.9 0.3 38 0.22 661
25mph 14.9 0.1 32 0.28 545
This was at 29BTDC?????? Does this sound right?

My tests:
Test 1: CO2 O2 HC CO NO
15mph 14.2 1.3 10 0.01 1930 FAIL (max 815)
25mph 11.6 4.8 7 0.00 870 FAIL (max 754)
Timing at 20BTDC

what I did: Read a lot! Changed EGR solenoid, looked for vacuum leaks and changed a few hoses. Learned what the Black Box was!!! Was really daunting and intimidating, I know cars pretty well but this car was loaded with vacuum lines, EVERYWHERE!!! Checked plug gap, wires, cap/rotor, all recently replaced. Oil was also fresh. Checked vacuum at EGR and at Black Box, replaced a few more questionable vacuum hoses (one was bad that I missed first go around.

Re Test numbers:
Test 2: CO2 O2 HC CO NO
15mph 13.2 2.4 12 0.01 1485 FAIL (818 max)
25mph 11.8 3.8 21 0.02 619 PASS!!!!!! (754 max)

Set timing to 18 BTDC.


Re testing tomorrow. I read that high octane fuel burns at lower temps so put in 4 gal of 98 octane gas, and Lucas fuel Deep Clean, going to reset the timing- when I set it at 18BTDC I didn’t plug the top vac line on vacuum advance on dist, the top hose looking at it from the front.

Appreciate your input on what else to try/do.

Thanks in advance.

[jzdude]

NOX is usually problems with the EGR(or clogged EGR passages in intake) or the catalytic converter. Carbed vehicles always have a lot of carbon buildup so it might be EGR related.

[Dr_Snooz]

Start by setting your timing. Leave the vacuum lines connected and put it at 15* BTDC.

Then look over your EGR system carefully. Put a vacuum pump on the EGR valve. Pump it down and see if the engine stalls. If not, then you have issues with the valve. It might be stuck or the channels might be coked up. If you're not getting a Check Engine Light, then that would be further evidence that the channels are coked up. Drill them out and clean them up.

Like jzdude says, NOx problems are almost always EGR related, but even so, when was your last tune up? What grade of gas do you use?

Good luck with the test.

[kojo96]

EGR working, vacuum at both ends, clean under the valve, new gasket. EGR valve lookes pretty new. Can I run that kind of timing??? Kinda makes sense as the last owner passed with timing at 29BTDC. Kinda shying away from drilling out the plugs, havent found them yet. Are they under that black plate/box behind the valve cover??

[jzdude]

EGR working, vacuum at both ends, clean under the valve, new gasket. EGR valve lookes pretty new. Can I run that kind of timing??? Kinda makes sense as the last owner passed with timing at 29BTDC. Kinda shying away from drilling out the plugs, havent found them yet. Are they under that black plate/box behind the valve cover??

I think smog technicians check the timing (its been required for a while) and you can only be 15 +/- 3 BTDC (automatic tran, in-gear, vacuum advance connected) to pass.

[POS carb]

I agree with dr snooz, too much timing advance. Your distributor has two vacuum advance lines. They should both have vacuum with a cold engine and the outer should not have vacuum once the engine is warmed up. Your mechanical advance may also be jammed on full advance.

When I had to do my Cali smog back in the day I had similar results, mostly NOx and timing problems. I put a metal beebee in the outer vacuum line to block cold advance (thermovalve failed, I did not want to replace it)
I also did some reading and based on what I read I put some rubbing alcohol in the tank (probably helps with CO), over-inflated the tires, and made sure the motor was nice and hot from driving when I pulled up.

After this I passed.

[POS carb]

the O2 seems to have gone up too from the previous owner, you may have an exhaust leak, however I think your #1 problem is the timing advance. I'd fix that first

[kojo96]

Re tested yesterday- replaced the cat, readings were:

15mph 106 max is 815
25mph 871 max is 754

Timing set at 20 BTDC (timed with the vac advance plugged)
99% rubbing alcohol in tank (full) 2 16oz bottles.


It was really hot out at time of test- I wasen't thinking, 97 degrees, 2 fans blowing on engine at time of test.
Going to check vac advance, think I’m advancing to much at higher rpm???

[jzdude]

If the both vacuum advance hose are plugged... it should read 4 BTDC.

[nswst8]

Seafoam it.

[ecogabriel]

I am not into carbed, but I know from NOx emission failures in EFI cars that they are EGR-system related, or cat related. Fuel-air mixture may affect NOx levels too.

http://www.auto-repair-help.com/auto...st_failure.php

Get the engine timed to specs as others have suggested as first step, and move from there; enriching fuel-air mixture may lower NOx levels (but increase HC and CO levels). Your first failed test and re-test apparently show lower HC levels compared to those of the previous owner.
Besides timing adjustment, replace O2 sensor(s) if you have no record of recent replacement; it should have been replaced when installing a new cat anyway.

[edit] When taking the car for testing, make sure you drive at high engine rpms to warm up the cat converter, and keep the engine running partially accelerated before getting to the dyno.

[Dr_Snooz]

How to pass smog

[2ndGenPreludeSi]

Seafoam it.

Do this!

[POS carb]

i still think 20 is too high... if you're failing NOx back it off to 16

[Dr_Snooz]

I believe California will fail you if the timing is too far off, even if you pass on the gases.