My maro was failing all three emissions tests but after replacing the EGR my NOX went down to passing. I am curently failing the other 2 by more than double
I have a new O2 sensor, PCV, Fresh set of plugs, wires, cap and rotor. The timing is correct. I have not replaced the smog pump or the cat. Could one or both of those be causing me to fail so badly? Is there a more serious problem hiding somewhere under my hood Any help or advice would be great. Thanks in advance.

 

try QUALITY FUEL and some cleaners.

 

A few things...

CO goes up when the engine isn't getting enough air. Do you have a new air filter? Have you cleaned out your throttle body with a spray cleaner?

HC goes up when the combustion process isn't complete. HC's basically mean "unburnt fuel". (Some trees release HC, too!) I would say to check over your ignition system. They say one misfiring cylinder can throw off emissions enough to cover 20 cars!

Test each spark plug wire with a multimeter; make sure they all have close to the same resistance. Look for corrosion inside any of the spark plug boots, on the terminals. Do you have any loose wires on the distributor cap? Are any of the plug wires arcing? To check that, run your engine at night (be careful not to get you or your clothing or your hair or etc caught in the motor) and look for blue sparks jumping "out" of the wires. A blue glow around the base of your spark plugs is normal.

Pull your plugs, make sure they all "look" the same (color-wise and deposit-wise). Clean them with either some find sandpaper, or a gentle wire brush. My dad has a spark plug gapper that has a brush on it; you might want to look for one. Make sure that your gap is at the stock 0.045 (for 85-up f-bodies)... if it opened up too far, the coil might not be giving a strong enough spark.

Pull the distributor cap, and flip it over (label your wires before you do this so you get them back on in the right order). Check the inner terminals for corrosion, and check the rotor for corrosion. If corrosion is there, remove it with a fine-toothed file or fine sandpaper. Be careful to sand the terminals "flat", and not to put any funny curves in them. If you haven't replaced the cap/rotor in a while, now might be a good time to do so.

You didn't say what year your car is... but your cat could be at fault. The cat helps to change HC and CO into H20 and Carbon. Later model 3-way cats also change NOx into something harmless. These usually have the smog pump hooked up, and the smog pump adds an oxygen molecule to change NOx into NO2 (not N2O, aka "nitrous", but NO2) and CO into CO2. If your car is old enough, the cat could've taken a crap (haha) and the pellet bed could either be destroyed, or coated with so much stuff that it's not working well. (An overly-rich engine can destroy a catalytic convertor due to unburnt fuel attacking the pellet bed.)

Was the test performed while your motor was HOT? Or did they let it cool down before they tested the car? Were you waiting on a long line, and the car was idling? The cat can get loaded up and not work properly; a quick blast on the highway is all that's needed to get the cat working well again.

I believe you're running rich, since your CO and HC are high. If your CO was high but HC was normal, that usually signifies a lean condition.

Good luck...

 

The car in question is the one in my sig. I had to wait about an hour or so in line the car was running the whole time. They shut the car off for about 2-3 mins before the test. When I get some time (and a little more money) I will replace the cat and pump. I Just replaced cap, rotor, plugs, and wires about 200 miles ago. I also re-set timing. Are there any "tricks" I can use to lower my CO and HC's(besides better gas and some and cleaners)?

 

YEAH
Change you oil.
Old engine oil stores gas vapors.
Which reappear during the smog test.
Change your oil and check all vacuum hoses.
AND I use Liquid gumout, (2 bottles) & premiunum fuel.
Drive on the freeway, real fast, then go for test.
I DOUBT you need to change a smog pump nor the CC
OH OH OH
Are they LIFTING THE GAS PEDAL REAL QUICK AFTER THE HIGH SPEED IDLE TEST?
Favorite trick to make mechainc more money.
THEY HAVE TO SLOWLY LOWER RPMS so you do not get extreme pollutant build ups that exit outta pipe during the smog testing.
Good luck!

 

OOps, didn't notice the sig; I forget, when we reply and "look back" at the messages, the sigs drop off.

And, I could've sworn I just gave you tips on lowering HC and CO. ?? It doesn't matter when you replaced anything last. If you fail again, or if your plugs still look clean and the cap/rotor are still fine and timing is still accurate, you might have to replace the cat. Get the bolt-in high-flow one from Summit Racing for $80 instead of paying a local parts store $100 or the dealer $300.

 

Re-reading the answers.
I really think you failed due to your "sitting" situation & the "idling for an hour, then shut off & restart.
Expalian why that happened.
I believe ANY car, given that "problem-idle/sit/shut off/start" would fail, also.
I truly doubt your CC is bad.
IT's amodern design.
AND hook back up the throttle body stuff, proper.

 

The car was idleing for an hour because I was waiting in line for my turn(this was recommended to me to keep the cat hot). Whenever you finnaly make it into the testing bay, they shut the car off for a few mins while they hook up the sniffer to the pipes, and get the test loaded on the computer.

Would not having those two coolants lines running to my TB really affect my emissions?

 

I could'nt pass my emissions either. I wound up faily my hydrocarbons by .1! I hate the smog ****'s.

 

Gotta love the cornfields of Illinois and NO EPA!.

 

I would still do a quick check of the cat.

jack the car up a little and get a good look at it. If there are any cracks, or large amount of discolloration it should be replaced.

When a car is run to rich for to long of a period of time it will over heat the cat. This will cause the insides to begin to melt. Maybe not completly but enough to cause a minor blockage or not to function corectly. The discolloration is a sign that your car has been ruinning to rich.

Remember that a cat is designed to last the life of your car as long as it is in good running order. Obviously this is not all ways possible, but it shouldn't be going bad every 50,000 - 100,000 miles.

 

Suggestion.
BE FIRST IN LINE!
Making you wait an hour for this test?
Is AZ now NJ?!?!?!?!!?
BUT...
Hooking up the TB isn't that hard, is it?
IS the oil changed?
The air pump isn't bad (to me) IF it spins freely.
CC may be bad, but..How many miles? It is original?
Can you do a PRE TEST before they test you?
In CA you still can. BUT you do pay for it, too.