I remember reading a thread somewhere on how to pass emissions. My beater car passed HC and CO with flying colors, but failed miserably on my NOx count (nearly double the limit). From what I remember, this means there's a carbon buildup in the intake / injection system. BG44K is supposed to cure this, but I'm not sure on how to properly clean the valvetrain. Should I buy two bottles? One to put in the gas tank and another to clean the valvetrain? How do you recommend I clean the valvetrain? TIA

Car is 91 Accord LX with 294,000 miles. Runs well, still gets 31-32mpg city, A/F 14.7.

 

I don't think there are any "quick fixes" for failing double the maxium. If you have almost 300k on the original cat. It's past due for a new one.

 

Why would you say that? The car runs perfectly well (although it needs a new motor mount). I bought this to serve as a commuter car, and it serves this purpose exclusively. My HC counts were at the 10% threshold, and my CO% counts were at the 1-2% threshold. So the problem is specific to NOx. I don't need uneducated responses like "you need a new one".

 

Check your EGR for vacuum when you rev it to 2500rpm(if none, check vacuum routing).If you have a vacuum pump apply vaccum to the EGR and see if your car stumbles. Doesn't stumble? Clean your EGR Passages, and recheck.

Once you fix that problem, and it doesn't pass. I bet the cat is way below efficiency, and may need to be replaced due to high milage.

Hope that was better.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by John &raquo;</TD></TR><TR><TD CLASS="quote"> I don't need uneducated responses like "you need a new one". </TD></TR></TABLE>

he said he thinks you need a new caT not a new car...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by John &raquo;</TD></TR><TR><TD CLASS="quote">I remember reading a thread somewhere on how to pass emissions. </TD></TR></TABLE>

Here is the thread: https://honda-tech.com/zerothread?id=313708

I know the bg44K does wonders, there is also a product out called seafoam

Here are a couple threads on seafoam:
https://honda-tech.com/zerothread?id=452806
http://auto.snowsuperstars.com/seafoam.html &lt;===a really good how to

You may also want to check your timing, clean the appropriate air filter, iacv and also check dizzy, plugs/wires

Hope that helps out

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by VRDrvr &raquo;</TD></TR><TR><TD CLASS="quote">

Here is the thread: https://honda-tech.com/zerothread?id=313708
</TD></TR></TABLE>

That's the thread I was reading before... looks like it's an EGR problem. RotaryBzzz hasn't posted in 10 months, so has anybody actually tapped into the EGR port to clean it? Or is there another way to clean it out.

Oh Crap, sorry I misunderstood your original post... how would you recommend that I vacuum the EGR port?

 

You would need a vacuum hand pump to check if the EGR passages are clean. I can't seem to find the bulliten where you have to drill on top of the intake runner to clean the passages.

 

When I failed the NOx the only thing the fixed the problem was replacing the cat. With that many mile on it you prob need a new cat anyway.

 

Follow-up. I paid a shop to clean the EGR system last Friday, and upon doing a road test after they completed the work, the thermostat hung and blew the radiator. Immobilized, I towed the car back to my house and replaced the radiator yesterday. Took it to be reinspected this morning, and it passed (yay!), but barely. NOx counts were lower, but now the HC counts are high. When I had the test done two weeks ago, my HC counts @ 25mph were 40. Today they were 107 (limit is 108). Any ideas? Is it possible the remaining BG44K in the tank of gas did this?

 

I doubt the remaining bg44k in the system would cause higher hc counts...but I could be wrong :shrugs: . Have you thought about replacing your cat or has it been replaced?

If you have had your egr and majority of the fuel system cleaned I would then suspect your cat next .

Congrats on it passing

 

Found a little more info for j00 :

<u>HC</u>:

Hydrocarbons are unburned fuel. A properly running engine will produce some HC's. On most late model vehicles in good mechanical condition and equipped with functional emission controls, HC measured at the tailpipe will be very low.

The presence of HC in the exhaust shows unused energy (fuel) going out the tailpipe.

Excessive HC in vehicles is the result of incomplete combustion, which could be caused by ignition malfunction, mechanical faults, vacuum leaks or fuel control or fuel management problems.

<u>NOx</u>:

Unfortunately an engine designed and tuned to produce low CO and HC produces high NOx The hotter an engine runs the more power it delivers, the more NOx it produces.

Late Model vehicles operate with a very lean A/F mixture so the NOx is very high and a "three way Catalyst is incorporated converting CO, HC and NOx.

A device called the E.G. (Exhaust Gas Recirculation) Valve was designed to lower the combustion temperatures by recirculating exhaust gasses back into the combustion chamber.
/\ would explain why your NOx readings were down .

 

Car could have not been properly warmed up? But yeah you passed..and the car drives wonderfully.. So don't worry about if it's just your commute car.. but anyways.. I told u so =P

Yeah once again it passed. Just drive it for another 2 years and see what happens.