I passed no problem 2 years ago, but this year I can't seem to pass because I have too high HC level. I took it in a few weeks ago and the HC level was at 4.5 and it should be below 2. So I decided to change the plugs and see if it helped. I took it back for a re-test and now I am at 10.5! I don't understand what the problem is. I took it to a local shop and the mechanic told me that it was running very lean, hence the high HC level. I'm confused because I smell gasoline occasionally. Any help would be greatly appreciated. Thanks

 

Any smoke at start up or while running?

 

I hadn't noticed anything, driving or start-up, until once last week. When I started it up after letting it sit for 30 minutes, a puff of smoke came out of the tailpipes, but I was suprised by it so I didn't notice the color.

 

High HC can be caused by high or low AFR. Gap the plugs correctly and run platinums? Might benefit you to check for misfires. Have you had a tune on the car since you installed the exhaust system on your car?

 

Could also be the EGR valve... run some fuel system cleaner and rxp gauranteed to pass through the system. One of the lower percentage causes but is very possible is blow by/bad valve seals.

 

I haven't had a tune since the header installation, but I put them on 4 years ago. I just passed without a problem 2 years ago, so I would be suprised if they had anything to do with it. Thanks for the input

 

I'm willing to bet you need a good tune up with some fuel system cleaner. Be sure to drive the car around with the new components for a while to let the PCM relearn the curves.

 

Does anyone else have any suggestions?

 

Tune up. Plugs and wires, change the oil and put the 180 T-stat back in. Reset the fans if your changed their settings and reset the computer. You are running a cat correct? I know I just failed for high HC and I put my stock T-stat back in and threw some rubbing alcohol in the gas tank. Worked good. for me. Good luck....John

 

I'll bet you that your leaking raw fuel either from your Emissions canister and/or the tube that goes from the canister to the fuel tank. This also explains your gasoline smell. The tube should be firm, not spongy or soft. Unfortunatly you need to drop the gas tank to get at it (unless you have done the hatch mod).

High HC = Rich (if you're not leaking raw fuel), duno what your mechanic is talking about. HC basically is unburnt fuel. NOx should mean overly lean...

The IM240 test here uses big hoses attached to the exhaust but they suck so much air in that everything around the exhaust gets pulled in too. Whats right near the exahaust? The fuel tank... if its leaking vapors they get sucked right into the machine.

 

As already mentioned, HC is unburned fuel. Rich not lean. Lower spark energy increases the unburned fuel as does a few other things. Not sure how many miles is on the car since you did a tune up 4 years ago but it sounds logical that it should have a complete job. Plugs, wires at least cap and rotor, fuel filter, air filter and new O2's.

The other question is does your state do static exhaust testing or do they do it on a dyno like some other state? If it's on a dyno, the EGR may play into the equation. If static it will not.

 

Technically high HC and high CO would be rich and high HC w/ high NOx would be lean. You can have high HC on both extremes. What do your other emmissions look like? NOx and CO

 

Is your car failing on the idle emissions? If so you can bring down the HC/CO levels by bumping up the idle a little bit. This is definately works to reduce CO anyway.

 

Here are the numbers from the test:
HC - 10.3591 (limit 2)
CO - 12.3718 (limit 20)
CO2 - 545.7681
NOx - 1.6014 (limit 6)

Everything passed very easily except for the HC level, which is why I am so confused.
A friend of mine told me that if I put a lot of cans of Heat (basically alcohol) in the tank, it will pass. But I don't just want to pass, I want to fix the problem.

 

Quick-z your getting the same results as i did with CO/HC/NoX. you have a fuel leak somewhere, im quite sure of it