ssions ith high readings of HC and CO.Failed emissions test

[pnutbuddy]

I purchased a 1990 240sx back in January of this year, now needs to get inspected. It failed the emissions with high readings of HC and CO. The HC only slightly above the standard while the CO is 4 times the standard! The car runs and drives great, I couldn't beleive it failed! Any idea's as to where to start looking for the problem? Or should I just take it in and have it professionally diagnosed?

[asoomal]

I'd start of with a full tune up and go from there:

NGK V Power plugsNGK WiresNew Cap and RotorCheck timingRun a full can of Seafoam through the gas tank to clean injectorsClean MAF and throttle body

Might as well do an oil change for the hell of it.

If it still fails, you might need a new cat.

Edit: Also do the fuel filter.

[Wc240]

post a picture of the VIR(emissions printout) theres no reason to do all of thats stated above when you can look at the printout and get a better idea of whats going on. post a pic that you/we can clearly read the info

[pnutbuddy]

I dont have a way to post a copy of the report, but here it is: HC(ppm) standard is 174 @ 2300 rpm, current reading is 201 - failHC(ppm) standard is 180 @ 1500 rpm, current reading is 221 - failCO(%) standard is 1.12 @ 2300 rpm, current reading is 4.47 - failCO(%) standard is 1.01 @ 1500 rpm, current reading is 4.11 - failCO2 = 0.2 @ 2300 rpm, 0.5 @ 1500 rpmNox(ppm) standard is 1258 @ 2300 rpm, current reading 661 -passNox(ppm) standard is 1378 @ 1500 rpm, current reading 563 - passDILUTION: standard is >6.0 @2300 rpm, current reading 16.67 - passDILUTION: standard is >6.0 @ 1500 rpm, current reading 16.31 - passThis is what the VIR states, also all other safety items passed. Any help is appreciated, thanks. I have been told to just add a gas additive that guarantees to make your car pass the emissions test, to replacing different sensors, ie the O2, exhaust gas temp., egr problems, replace the cat...you see my dilemma, too much advice from parts houses! Again, thanks for any help.

[Wc240]

egr is not a problem as your passing for nox(buy the way, you have some lax standards down there) start buy checking your air filter, if its really dirty it'll couse you to run rich. how long has it been since you changed your oil? old oil will couse you to have slightly higher HC levels, but not that high. the VIR should say what your timing was at, what is it? you may consider the cat due to the fact that, with your elevated hc/co levels, your co2 is low. you want that to be high. dont know about down there, but over here we like to see that around 13%. but it could be becouse of how rich you are. id suggest taling care of the rich condition before replacing the cat. how old is your o2 sensor and are you able to test it? what about vacuum leaks? also, clean your MAF, its free and never a bad idea. i clean mine at every oil change