Happs

My 1992 Honda Accord failed the emission test today for a too high NOX reading. The applicable standard is 2.50 and my car's reading was 2.61. I've read that high NOX has something to do with a malfunctioning EGR valve. Will replacing the EGR valve guarantee that I pass the emissions test? I don't want to start throwing money at all kinds of parts. Should I buy genuine Honda brand parts or are Standard Motor Products parts that are available on Amazon.com for a lot less $ as good quality get the job done? In case it helps, the Hydrocarbon reading was .60 and the Carbon Monoxide reading was 8.81.

poorman212

No it will not....now you might try cleaning it and the ports on the intake. Is this due for a tune up.

MAD_MIKE

In the FAQ there is a PDF file on how to clean the EGR ports on the intake manifold and how to remove/replace the egr plugs. High NOx is usually from either excessively high combustion temperature/pressure or a faulty/plugged EGR system. With higher mileage cars its usually the later.
Although Honda brand parts are preferred the dealer prices can be pretty steep. Keep in mind that some OEM parts are made by other companies such as Denso. Standard Motor Products can be hit/miss.

Happs

I'l try cleaning it. The car has new spark plugs and spark plug wires and a recent Sea-foam treatment. Since I need to provide receipts to substantiate repairs (can't get a receipt for just cleaning), would buying a new oxygen sensor help? The car only as 46,000 original miles.

poorman212

Not sure why a receipt is needed, different states and counties have different laws.

Would the seafoam and the carb/tb cleaner not work? Or at least buy a new egr valve gasket....might as well pull that and clean it too.

Happs

Well, I had the oxygen sensor changed (the original looked bad), the pcv valve changed (the original wasn't clicking and looked caked) and the EGR valve cleaned (lots of gunk) and I passed the emissions test. The NOX readings went down, but the hydrocarbons and carbon monoxide readings were unchanged. I am running regular unleaded fuel. The car had a Seafoam treatment 2,000 miles ago. The air filter was dirty but I didn't change it before the retest because I wanted to see if the a new oxygen sensor, pcv valve and egr cleaning would help. I'm going to change the air filter soon. Will that make any significant difference on the next test?

I didn't check for vacuum leaks. Am wondering what I should look at next, in preparation for the next test in two years.

holmesnmanny

You need to clean the egr ports not just the valve and valve area.

Throw in some new plugs, and a new cap and rotor to help the co and hydrocarbon readings.

jdmcertified909

So your car passed? Seafoam does miracles doesnt? Lol I know it did for me HUGE!!! Difference

holmesnmanny

lol I read next test in two years as next test in two days. muh bad

MAD_MIKE

Air filter will help with HCs. If the engine has to work harder to pump thats wasted power. Always keep your engine in tip-top shape. If for nothing else, to keep your MPG high.

Seafoam the tank 1oz/gallon; oil 1oz/quart; with the engine running use an unused vacuum port, a piece of hose, and siphon the Seafoam.
Or you could bring it to a mechanic who can flow/clean the injectors.
Recently know of a fellow who couldn't pass emissions on his '85 CFI Mustang
Impressive. Varnish on the valves can be a ***** on power too.

One thing of note, keep the tank 1/2tank or more full. I've been goofing on the wifes Mazda. It's old 190K+ miles. It used to get 30-31MPG easy, recently has been getting 26MPG, changed fill-ups to 1/2 tank and 35MPG has been the average Started a SeaFoam treatment last week as well. Simply the bottom of the tanks become fouled with crud and junk, run the fuel below half tank and this begins to effect the fuel economy. The correct solution would be to clean the tank. But for now I'm just sticking with 1/2 fill-ups. FWIW, same fuel, station, pump, use the tripometer to gallons for calculation.

Happs

Well, I went for my biennial test and the car failed the emissions test with a high NOX. The standard is 2.50 and my car was 2.52. My car also failed the gas cap test. I drove hard on the freeway before the test, there was a 15 minutes wait in line, car idling the whole time, over 100 degrees out, so it was well prepped for the test. Looking at the past 3-4 times the car has been in for an emissions test, the NOx has always been high. Also of note, the actual test on the dynamometer took a very long time--almost as if the technician did the test twice. Is a new catalytic converter a guaranteed way to lower NOX? If so, which one should I buy?

MAD_MIKE

Were the individual ports for the EGR cleaned and the passage to those ports, or just the EGR valve base?

Happs

Just the EGR valve base. I read the FAQs on there and the EGR port cleaning is pretty involved and is best left up to to a shop. I've emailed some shops to ask the costs of both EGR port cleaning and a new catalytic converter.

NZXTInerTia

Its not involved at all! Really, its just another thing you should probably learn to do.

Three bolts for the rail, and ~five for the cover. Take a vacuum and a pick and chisel the holes out. Some people choose to drill them which does the same thing. Its honestly so easy to do and I hate seeing people spend money on simple repairs.

MAD_MIKE

He has a CB not a CD, hence holmesnmanny quote of , in the Time attack, EGR passage cleaning. thread.

Happs did you ever look over this ? http://home.comcast.net/~em-engineering/T2T013.pdf

NZXTInerTia

Wow I totally skipped over that didn't I. I totally read 92 and it didn't even click.

Disregard my information!

Happs

No, but thank you very much for the link. Also, am I correct in driving the car for 10 miles and letting it idle while waiting for the test to make sure it's very warm?

MAD_MIKE

A drive that will get the drivetrain good warm will greatly help in emissions testing. However if your EGR system is not functioning correctly due to blocked ports, you are going to have a hell of a time passing.
Don't forget...
Just incase the old ones you pull out get damaged.