Emissions in MA

[xpeteyjtx]

I need some advice for passing emissions
Here are the numbers
HC g/mile Reading=.6 Limit=1.2
CO g/mile Reading=2.49 Limit=20.0
NOx g/mile Reading=2.94 Limit=2.5
CO2 g/mile Reading=346.14 Limit=NA
So as you can see, I failed the NOx portion. It passed everything with flying colors, but for some reason, there is a little problem. The timing is at 10, there is a MSD Blaster coil, and a K&N panel air filter (These are the only mods). 63,000K. When I went to get it tested, I was running 93 octane and I last got an oil change in November and have only driven 400 miles since then. When looking at the stock engine temperature guage, the needle looked lower than usual... I think it was near the first letter on the bottom of the guage... it is usually a little higher.

When I first purchased the car, about a year and a half ago, it passed inspections with the timing set at 14-16 degrees.

So what should I do? I dont want to spend much fixing this. I was thinking that I should change the oil, since it has been 5-6 months , advance the timing to 12-14, and drive it hard before I get to the shop so its nice and warm. Anything else? Thanks for the help in advance guys.

 

[1991vert]

if anything you want to lower the timing and put in 87 octane. 93 will throw higher emissions. i dont see why you arent passing with 10* timing. that's stock

 

[stang&2Birds]

In order:
Make sure the air filter is clean.

Change the oil and filter. That's important for engines like the 5/0 that burn a lot of oil (1qt every 2K to 8K miles from the factory).

Change the O2 sensors (they run rich as they age).

For ~$300, replace the h-pipe cat. New cats always help a ton.

Of course, make sure the car has run at least 30 mins before the test so that the engine is *fully warm*.

 

[1991vert]

In order:
Make sure the air filter is clean.

Change the oil and filter. That's important for engines like the 5/0 that burn a lot of oil (1qt every 2K to 8K miles from the factory).

Change the O2 sensors (they run rich as they age).

For ~$300, replace the h-pipe cat. New cats always help a ton.

Of course, make sure the car has run at least 30 mins before the test so that the engine is *fully warm*.

no need to replace the sensors or hpipe. dump a bottle of "guarenteed-to-pass" in the gas tank and follow the directions

 

[stang&2Birds]

no need to replace the sensors or hpipe. dump a bottle of "guaranteed-to-pass" in the gas tank and follow the directions

Have you read the directions? Do you know what it does? It will NOT help AT ALL if you have dirty oil, clogged cats, clogged air filter, or old O2 sensors.

That junk basically "kinda-sorta-semi-helps" to clean the injectors and "possibly" the combustion chamber. IMHO, don't waste your money.

Because of the newer gas formulations, clogged fuel injectors are pretty rare today. If anything, they now tend to leak before they clog. Of course, if someone hasn't replaced their fuel filter, then who knows what crud is in the fuel system.

Sorry, I based my decisions on real science and facts. Not by BS advertising.

 

[stang&2Birds]

BTW: With the readings that xpeteyjtx had, I could probably make a TON of money by having him use my DYNO PROVEN technique of swinging a dead rubber chicken around his head and saying DOGGIES RULE!!.

Heck, we just go 10 times with different weather conditions, then I can LEGALLY say PROVEN TO HELP YOU PASS EMISSIONS!. I can then add that to my "DYNO PROVEN" claim. Sell it on ebay along with the other snake-oil BS, and screw people out of their money.

However, MY goal is to help prevent people from getting screwed by scum that know they are selling snake-oil, and couldn't give a rat's @ss that they are stealing people's money.

 

[vristang]

I need some advice for passing emissions
Here are the numbers
HC g/mile Reading=.6 Limit=1.2
CO g/mile Reading=2.49 Limit=20.0
NOx g/mile Reading=2.94 Limit=2.5
CO2 g/mile Reading=346.14 Limit=NA
So as you can see, I failed the NOx portion. It passed everything with flying colors, but for some reason, there is a little problem. The timing is at 10, there is a MSD Blaster coil, and a K&N panel air filter (These are the only mods). 63,000K. When I went to get it tested, I was running 93 octane and I last got an oil change in November and have only driven 400 miles since then. When looking at the stock engine temperature guage, the needle looked lower than usual... I think it was near the first letter on the bottom of the guage... it is usually a little higher.

When I first purchased the car, about a year and a half ago, it passed inspections with the timing set at 14-16 degrees.

So what should I do? I dont want to spend much fixing this. I was thinking that I should change the oil, since it has been 5-6 months , advance the timing to 12-14, and drive it hard before I get to the shop so its nice and warm. Anything else? Thanks for the help in advance guys.

My General Thoughts
You said that you were running cooler than usual. That would normally increase your HC's and decrease your NOx.
Oil changes and O2 sensors will have no affect on your NOx, atleast not significantly.
Your numbers actual say that you have a pretty decent motor.

Guaranteed to Pass probably will not help either, but I have no direct experience there. It seems to me that most of these types of products focus on HCs and CO, leaving the consumer to deal with NOx.

I believe the stock cats were 3-ways, so new cats may help. But my memory is pretty hazy here.

The Nitty Gritty
If the EGR system is working properly you should have no trouble passing next time through; you are actually pretty close now.
Start with pulling the codes from the computer. You need to rule out a fault in the EGR system first.
Most likely there is a problem with the EGR, but it is not severe enough to trigger the CEL.

Good Luck
jason

 

[xpeteyjtx]

Im not going to use any **** that claims to help emissions... I don't really buy the claim. Will I benefit from changing the fuel filter? Im pretty sure its stock. If so, do you guys have any instructions? I dont want gas in my mouth.

It pisses me off knowing that it didnt pass the NOx test, i mean, the damn thing is stock and hasnt been messed with. Oh well... thanks for the help guys.

Jason, I was thinking about pulling the codes, I will probably do that tomorrow. Thanks.

 

[xpeteyjtx]

I have a question... since I was running slightly cooler, wouldnt that increase emissions in general, including NOx? I thinking that the higher the engine temp, the less bad stuff emitted, since the HCs can more easily fully combust. Im not questioning your intelligence or anything, just trying to understand a little more.

 

[vristang]

I have a question... since I was running slightly cooler, wouldnt that increase emissions in general, including NOx? I thinking that the higher the engine temp, the less bad stuff emitted, since the HCs can more easily fully combust. Im not questioning your intelligence or anything, just trying to understand a little more.

It's cool to see that your putting some thought into this.

HC's will decrease with higher combustion temps. If you can get your coolant temp higher for the next test, you should see lower HC emissions.
What coolant T-stat are you currently using? A 180F or 195F should work well.

NOx is a completely different animal however.
In order to form Nitrogen Oxides (NO, NO2, etc) the temperature of combustion will need to be quite high. If the temperature isn't sufficient then no matter how much Nitrogen and Oxygen there is, you will not form any NOx. For example, there is plenty of Nitrogen and Oxygen in the air we breathe, but very little NOx (that was not put there by our cars ).
The EGR reduces NOx by reducing the combustion temps in the chamber. Exhaust gas is very low in oxygen, as it was all just burned during combustion. So when the lower oxygen levels of the exhaust gas hit the combustion chamber there is less oxygen to burn. Lower levels of oxygen lead to lower combustion temps, and therefore lower NOx.

I have a more detailed explanation here... http://www.freewebs.com/vristang/50emissionsequipment.htm

Let me know if it makes sense, as it is still in the draft phase.

jason

 

[1991vert]

Im not going to use any **** that claims to help emissions... I don't really buy the claim. Will I benefit from changing the fuel filter? Im pretty sure its stock. If so, do you guys have any instructions? I dont want gas in my mouth.

It pisses me off knowing that it didnt pass the NOx test, i mean, the damn thing is stock and hasnt been messed with. Oh well... thanks for the help guys.

Jason, I was thinking about pulling the codes, I will probably do that tomorrow. Thanks.

i used it on my car and it passed with flying colors. i dont suggest just throwing money out for new parts. and the directions say that you must have all smog equipment present or they will not guarentee it. fill up with 93, drive down to about 1/8 of a tank, dump that stuff in, fill up with 87 and you're good to go.

 

[1991vert]

It's cool to see that your putting some thought into this.

HC's will decrease with higher combustion temps. If you can get your coolant temp higher for the next test, you should see lower HC emissions.
What coolant T-stat are you currently using? A 180F or 195F should work well.

NOx is a completely different animal however.
In order to form Nitrogen Oxides (NO, NO2, etc) the temperature of combustion will need to be quite high. If the temperature isn't sufficient then no matter how much Nitrogen and Oxygen there is, you will not form any NOx. For example, there is plenty of Nitrogen and Oxygen in the air we breathe, but very little NOx (that was not put there by our cars ).
The EGR reduces NOx by reducing the combustion temps in the chamber. Exhaust gas is very low in oxygen, as it was all just burned during combustion. So when the lower oxygen levels of the exhaust gas hit the combustion chamber there is less oxygen to burn. Lower levels of oxygen lead to lower combustion temps, and therefore lower NOx.

I have a more detailed explanation here... http://www.freewebs.com/vristang/50emissionsequipment.htm

Let me know if it makes sense, as it is still in the draft phase.

jason

HC's are unburnt fuel. did you have your smog pump in place? that pumps fresh oxygen to the cats

 

[xpeteyjtx]

Everything is in place. I just pulled the codes and got 22, which is the BAP. Does the HC reading seem high to you?

 

[xpeteyjtx]

I just found a very thin, but an inch long exhaust leak on the passenger's side muffler, on the side closest to the h-pipe. Will this affect emissions? if it makes the numbers worse, I will have to fix it before I go back. Thanks again.

 

[xpeteyjtx]

I just pulled the codes with the engine running, Im getting 94, 44, and 33. Shouldnt these codes appear when the car is off also? Off to check the vacuum hoses now.

 

[vristang]

HC's are unburnt fuel. did you have your smog pump in place? that pumps fresh oxygen to the cats

I don't get it.
Can you elaborate for me.
I know what an HC is, just not sure what your point is

 

[vristang]

I just pulled the codes with the engine running, Im getting 94, 44, and 33. Shouldnt these codes appear when the car is off also? Off to check the vacuum hoses now.

94 & 44 are the air injection system, which I have no idea how to diagnose.
Try a search for these codes and a post from jrichker. I bet you will find a good troubleshooting guide that way.

For 33 you can pull the egr valve and try to clean it up. Carbon will build up inside these things and prevent proper operation.

A small exhaust leak at the end of the system, should have no affect on the test.

 

[1991vert]

I don't get it.
Can you elaborate for me.
I know what an HC is, just not sure what your point is

maybe he is running rich