She flunked the state emission test - any suggestions?

[100Dollar240]

Not that I'm surprised - after all, she has 232K logged since a birthday of '93, & I'm not sure what "tune-up" work had been done in the months prior to my purchasing it in January. The car's entirely stock & seems to run well. It's a daily driver with about 4 autocross Sundays under its belt. I run it on 87 octane with no protests. The state (MD) will make me shell out up to $450 in repairs in an attempt to correct my nasty pollutants, then give me an exemption & a pat on the head good for two more years. However, besides the usual plugs, wires, air filter, PVC valve etc. that I'll start with, is there anything else, such as the various sensors (EGR), that are the logical next step to replace in the event I flunk a re-test? I had also heard about a gas tank additive that "guarantees" a passing grade on an emission test, but I tend to be skeptical about instant cures. Any suggestions? Thanks, Ron.

[Checkered-Member]

What part did you fail? Too much NO, CO, CO2?

[100Dollar240]

It failed HC - State standard 1.0000 GPM, mine 1.9702 GPM....AND failed NOX - State standard 2.2000 GPM, mine 3.9247 GPM.Passed CO with no problem. Thanks for asking.Ron.

[D-3vil]

it's probably your catalytic converter...I don't know how things are in MD, but in Canada it only cost me $20 extra (on top of a tuneup prior to the test) at the time of the emission test, and the probe was held further away from the exhaust...the result? a clean pass.

After all, it's not like after spending $450 in repairs your car will run much greener. It's another way for the government to rake in some money that will never be used for the purposes initially stated.

just my $0.02

[180fan]

EGR. If you CO passed with flying colors and your NOX and HC's are high, you're running way hot in cylinders. Check the vac lines to your EGR and check it for function.

With the car running, push up on the saucer section of the egr and if your car starts to die out, it's still good but probably has the damaged vac lines. If it does not die, it's clean up time. Pull the pipe that connects the EGR and dunk that in cleaner ditto with your egr. Make sure the saucer section does not get in the cleaner though. If it's heavily clogged, use a screwdriver or a pipe/gun barrel cleaner to get more of the junk out. Try that and get a pre-test to see what's cookin.

tune up consists of:spark plugso2 sensor (for me at least)distributor cap and rotorpcv valvefuel filter.

most of that stuff you can find on PDM's website for reasonable prices.

[100Dollar240]

EGR. If you CO passed with flying colors and your NOX and HC's are high, you're running way hot in cylinders. Check the vac lines to your EGR and check it for function.

With the car running, push up on the saucer section of the egr and if your car starts to die out, it's still good but probably has the damaged vac lines. If it does not die, it's clean up time. Pull the pipe that connects the EGR and dunk that in cleaner ditto with your egr. Make sure the saucer section does not get in the cleaner though. If it's heavily clogged, use a screwdriver or a pipe/gun barrel cleaner to get more of the junk out. Try that and get a pre-test to see what's cookin.

tune up consists of:spark plugso2 sensor (for me at least)distributor cap and rotorpcv valvefuel filter.

Thank you, 180fan and others. I'll start with the EGR test & work from there. At least I've got 'til December to do the work.Too hot under the hood for me right now.I'll post a follow up if all works (or not).

Thanks again, Ron.

most of that stuff you can find on PDM's website for reasonable prices.

[onosqv]

And in addition to above. Do this before your smog check in case you don't already:

http://smogtips.com/six_things.cfm

not brain science, but every little helps .

[PapaSmurf2k3]

not true, if your car is running too hot in the cylinders, youd be burning all your fuel, and your HC reading would be low. (HC is hydro-carbon). HC can also go down with the investment of plugs/wires and such, creating better spark to burn more fuel. NOx is often effected by the timing, meaning that the exhaust stays in the hot combusion chamber longer, leaving more time for the NOx molecule to form at the high temperatures. with readings that close, you might be able to screw with your timing and do a tune up and get by, but mine were around there as well, and it wouldnt pass so i got a new cat and passed fine. another "theoretical" solution would be to go out and buy a bunch of dry gas and put that in your tank. dry gas is basically alcahol, and alcahol burns cleaner than gas, but who knows what kind of pinging or whatever it might do to your motor.

[180fan]

with cylinder temps high, you can still get an incomplete burn. I've gotten this rundown at least the basics from Nistech when i was running the smog hurdle myself earlier this year. Your EGR's main function is to reduce the cylinder temps by recirculating exhaust gas back into the cylinders. I also had the very same problem, with my EGR not getting enough backpressure to open the EGR which was causing my NOx to be super high although my other two numbers were well within spec. Assuming everything else to be stock, a simple tune up and possibly a clean up of the EGR should reduce the failing numbers.

[180fan]

damn double posts...

[93sleeper]

You could try running colder plugs to reduce cylinder temps.

Make sure the cat is warmed up fully before testing, like drive around a little and have the car idle while waiting for the test.

Also, you could try placing a rag over the air filter, I've heard this can reduce NOx

[xekushnr]

move to a state that does not do emissions tests. i always see posts ranting about emissions test, but i really cant relate. michigan isnt that bad after all

[Bigrolla]

HaHa I goto a ghetto inspection places n Louisiana. THey dont check emmissions but for $30 u can get a inspection sticker on a car with defects that arent obvious. I could get away with any motor swap or no emmissions components at all but u never know that could change one day but there is always some shady place everywhere.

[98s14inaz]

Yup definitely cat or o2 sensors. A full tune up and oil change wouldn't hurt either.