Failed Emissions!!!

TrueBlue95GT · May 6, 2005

I failed emissions with the stock 4 cat h-pipe. What can I do to pass emissions. I took off the EGR and Air pump. I don't wanna put those back on. But I also had the tweecer in there and I didnt think of changing the fan settings back to normal so it was still running on the N in the temp gauge. Also, I had the timing at 17. Tell me everything you know that could possibly help me pass emissions besides putting the air pump and egr back on.

donjohn · May 6, 2005

find somebody that accepts 50 dollar bills

TrueBlue95GT · May 6, 2005

I can't....Connecticut has this new emissions program where it's all private, but there are cameras watching the emissions test being done. You can't cheat the system. However, I was wondering what I could do to lower my hydrocarbons and carbon monoxide. I passed the NOx maximum limit with flying colors.

94-302-vert · May 6, 2005

Get new high flow cats?

Chythar · May 6, 2005

Well, that's the point of the EGR. It lets some of the exhaust back in to be reburned, thus lowering the hydrocarbons and carbon monoxide. Ironically enough, the EGR only works at part-throttle, so it has no effect on WOT. The air pump works with the cats, though I'm not exactly sure how. Perhaps adding backpressure and/or keeping the cats from getting too cool?

bimmertech · May 6, 2005

not so true about egr. egr is meant to lower nox wich forms at higher combustion temps. egr acts to cool the combustion process which in your case is not a problem due to your rich condition. i am not familiar with your process but used to due emissions testing in houston and have found that a new pcv, oil change and because you are running rich, if you have an adjustable fuel reg back it off a few psi before you go. but befor that do a battery reset to clear your adaptive values. please post exact numbers, including co2 and o2 if available.

fushnicken · May 6, 2005

Chythar said:
Well, that's the point of the EGR. It lets some of the exhaust back in to be reburned, thus lowering the hydrocarbons and carbon monoxide. Ironically enough, the EGR only works at part-throttle, so it has no effect on WOT. The air pump works with the cats, though I'm not exactly sure how. Perhaps adding backpressure and/or keeping the cats from getting too cool?

The Air Pump pulls back vapors from the cats to be reburned as well. In fact, running cats without an air pump is bad math. The chances of your cats getting clogged up are much higher without it. Most of the guys that remove the air pump assembly have o/r H or X pipes.

This is probably why you are failing. All the stuff that the air pump pulls back is going out your tailpipes.

bimmertech · May 6, 2005

air pump is used to warm up cats on cold start to get them oxidizing faster as well as get your ho2s in closed loop faster which is supposed to lessen emmisions. if your coolant temp is very low this can also prevent your ho2s from going into closed loop.

mo_dingo · May 7, 2005

lol...lets try this again.

The smog pump COOLS the cats so they work more effeciently......

Second, look towards your O2 sensors. They control a/f ratio during emissions testing, and if it is off, your emissions will sky rocket.

your fuel pressure has NOTHING to do with it. The O2's will compensate and decrease injector pulse width.

You still have the tube that runs from your header tube to the EGR right? Why not hook it back up. It's 2 bolts and one big nut.
Scott

way2fast4u · May 7, 2005

donjohn said:
find somebody that accepts 50 dollar bills

wow where do you go thats its that cheap .. Can you lead me in that direction!!!

TrueBlue95GT · May 7, 2005

I don't have the EGR because I did a fox throttlebody conversion, and the air pump gives oxygen to the cats so that less co is there and more co2 is there. It gives the oxygen in order for the catalyst to turn co into co2. I had a 266 in the hydrocarbon when I was only allowed 60ppm and I had 4.32% CO when I was only allowed .32%.

vristang · May 7, 2005

I just wanted to throw my knowledge out.

The cats work best when hot (within reason). The air pump is there to provide O2. This allows the cats to more effectively oxidize the unburned HC.

EGR does not reburn the exhaust gasses. This is a very common misunderstanding. EGR sends inert exhaust gas into the combustion chamber, which displaces O2. Less O2 means less oxidation (fire), and less heat. Heat in the presence of N and O produces NOx. The less heat the less NOx.

The O2 sensor can slowly start to give bad readings and should be replaced according to the factory schedule (50,000mi?) This could result in excessive HC.
The recommendation to check the PCV is good, but also check the valve cover to TB vent (especially if you have removed the valve cover baffles for RR clearance). Just make sure that there is not a large amount of oil passing through the tubing.

Backing off the fuel pressure should also help, if you have an adjustable regulator.

Are you getting any codes from the computer. This should be the first thing you check. It can tell you alot.

I hope I have helped.
If you get a chance please post what the requirement is and how you scored on the test. It would be interesting to see where you are now and where you are when you pass the test, after making the necessary changes.

Good Luck
Jason

bimmertech · May 7, 2005

look if you removed the smog pump would there still be o2 to oxidize to co in the cat. YES! your smog pump does not provide o2 for oxydation once your engine is warm, as evidence by vehicles that are made with an electric air pump that shut off once the vehicle is warm. backing off your fuel regulator will temporarily lean out your a/f ratio until your computer realizes and compensates for it, which if done at the right time could be hours after your test. you guys are killin me here, this guy has a real problem on his hand and the last thing he needs is more confusion by info that is half correct, i know intentions are good but trust me on this one. i have gone to many schools and have done countless emmisions tests and repaired failed vehicles. low nox high co indicates a rich condition, if you wanna fix it right you will wanna start of with o2s and go from there, but if you wanna just pass it listen to the advice given by myself and jason.

TrueBlue95GT · May 7, 2005

Alright, I found out that my Brake booster is leaking and therefore I have a vacuum leak. Also I have a small exhaust leak from the header to the h-pipe. If I fix these two things, do you think it would make my numbers a whole lot better? Also, with this post, I was looking for answers more like "put this product in the gas tank and it will definitely make you pass". I just need a quick fix to pass emissions so that I can get my car registered and then the pro chamber is goin right back on.

mo_dingo · May 7, 2005

That certainly could be your problem. Try it and see what happens.....

vristang said:
backing off your fuel regulator will temporarily lean out your a/f ratio until your computer realizes and compensates for it, which if done at the right time could be hours after your test. you guys are killin me here, this guy has a real problem on his hand and the last thing he needs is more confusion by info that is half correct.

OK, now that is funny. What you are saying is COMPLETELY WRONG!!!!!!!

Once the car has been running for a couple minutes, the O2 sensors will be online, and will INSTANTLY see the extra fuel and trim injector pulse width. INSTANTLY

Now, if you are talking about WOT runs, that is a different story. But last time I checked, you don't put the pedal to the metal during an emissions run, right?????

Not passing emissions is first and foremost an oxygen sensor problem (a/f ratio), or a catalytic converter problem.

If you a/f is off at all, it will raise emissions drastically. Of course, catalytic converters not working may also be your problem.

IDK about quick fixes. There are many. Try doing some searching.
scott

davins130 · May 7, 2005

put some peanut butter in your gastank, that should help you pass emissions.

1990LXDropTop · May 7, 2005

TrueBlue95GT said:
I failed emissions with the stock 4 cat h-pipe. What can I do to pass emissions. I took off the EGR and Air pump. I don't wanna put those back on. But I also had the tweecer in there and I didnt think of changing the fan settings back to normal so it was still running on the N in the temp gauge. Also, I had the timing at 17. Tell me everything you know that could possibly help me pass emissions besides putting the air pump and egr back on.

I failed here in MA a few weeks ago with the stock 4-cat pipe. I also had no air pump. The first time I was way over the HC limit, so I lowered the timing, lowered the fuel pressure, ran some 87 octane and I failed the second time. I had to hook the smog pump back up, although I just ran it to the h-pipe and not to the back of the heads. I went back the third time and still failed (even though the air pump did lower my numbers some). I then dumped a bottle of "guartanteed to pass" fuel additive into a full tank of gas, drove it until it was below 1/4 tank, and went back to test for the 4th time and passed with flying colors. All my numbers were way below the limits. The guy said it was the cleanest stang emissions wise he has ever tested. You really need that air pump on there if you want to pass. If you don't have an air pump you can try lowering the timing to below 8* initial, run 87 octane, and run either 5-6 bottles of dry gas, or you could try that "guaranteed to pass" fuel additive which works awesome. Good luck!

TrueBlue95GT · May 7, 2005

Thanks alot dude. That's the kinda information I was looking for.

MysteryMachine · May 7, 2005

why would you take off emission components when you have emissions in your area

BlackVert · May 7, 2005

we have emissions in my area, i just did mine and i passed on the first try, but i have all my emissions stuff still. the next one is not for 2 years. i'm still not sure if i'll have to take off the smog pump for the turbo or not.

which one makes a bigger difference, the egr or the smog pump?

Failed Emissions!!!

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