quote:

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Originally posted by 94Blackout:
Sorry, I need to edit my sig. These are the cars mods....

94 GT
Vortech S-trim supercharger, 8lbs
Trex fuel pump
30# injectors
Pro-M 80mm MAF
Race Systems custom Chip
255 Walbro Fuel pump

Car passed smog in 04 with the above mods, then these parts were added:

75mm TB + C&L intake plenum
Updated intake with aluminum crossover
Bassani Xpipe with cats

All the CO numbers passed with flying colors at idle rpms, and with the car at 2500 rpms it passed the HC and CO tests easily. It was just at 753 idle rpms that the car failed the HC.

The car was only warmed up for about 20 minutes before the smog. The smog tech even tried heating up the cats for a few minutes, although if you say it is a result of being too lean then I doubt that would make any difference.

You think if I removed the mods that were put on later it would pass, or do you think this is a result of the car beign out of tune?

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quote:

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Originally posted by jaybquick:
HC stands for Hydro Carbons. It indicates a lean codition. What were your CO% CO2% NOX readings? Was this a dyno smog? What part of the test did it fail? What year mustang do you have, what mods, etc, or is it the one in your sig?

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J - ? for ya

I always thought HC's were they amount of unburned gas molecules that were being detected indicating a slightly rich mixture.

I'm probably wrong and i know that you were a smog tech. before so i thought i'd ask.

Isn't that why they are labelled as gross polluters?


 

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Posted by 9lbpony (Member # 3510) on :
 
the trick is that you have to look at both HC and O2 to know what is going on. If the car is running rich you'd have excess HC but not excess O2. If the car is running lean (and thus misfiring slightly) you'd see HC and O2.

I'm convinced I could make a few $$$ selling an overdrive pulley for the smog pump. Swap it on before a test and inject 20-30% more air into the exhaust. Just the dilution alone would help...

That combo should be passable though - I've helped tune an S-Trim 347 with aftermarket heads/cam and 42# injectors to pass just fine. (same tune did wonders for the guys gas mileage)
 

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Posted by 94Blackout (Member # 2541) on :
 
There was no excess CO. I can't get the numbers, cause I have seemed to misplace the papers. So doesn't that mean I was running rich if there was too much HC and the CO was in line?
 

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Posted by jaybquick (Member # 4286) on :
 

quote:

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Originally posted by TRIXSNK:

quote:

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Originally posted by jaybquick:
HC stands for Hydro Carbons. It indicates a lean codition. What were your CO% CO2% NOX readings? Was this a dyno smog? What part of the test did it fail? What year mustang do you have, what mods, etc, or is it the one in your sig?

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J - ? for ya

I always thought HC's were they amount of unburned gas molecules that were being detected indicating a slightly rich mixture.

I'm probably wrong and i know that you were a smog tech. before so i thought i'd ask.

Isn't that why they are labelled as gross polluters?

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HC is completely unburned fuel. CO is partially burned fuel. CO is the first indicator of a rich mixture and once it is extremely rich the HC follows due to the miss. But a lean running car will have high HC and 02 however with our air injection systems it is hard to tell without actually disconnecting the air injection hose from the fitting to the cats to tell if it is injecting or not.

TO hokey it you have to remove or add vacuum to the valve by the header, that one selects between the head which is used for cold and the cats for when warm. The valve near the pump is for on/off. You may have to bypass both temporarily. However the raising idle thing may work, try to get the guy to throw his sniffer in the pipe for ya before ya start. You are pretty darn close. It would be great if you supplied us with all your readings.

[ January 14, 2005, 10:53 PM: Message edited by: jaybquick ]
 

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Posted by 94Blackout (Member # 2541) on :
 
Ok, I will try to get the smog report numbers. However, I just realized that a wire from the EGR looked like it was unplugged. Could this have possibly been the culprit as well? The smog tech doesn't unhook that during the test, does he?
 

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Posted by jaybquick (Member # 4286) on :
 
The egr not working would not affect your idle emissions. He may have unhooked it to check the egr, but I don't see why. That is not the procedure I used to use.
 

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Posted by 94Blackout (Member # 2541) on :
 
Here are the official numbers for idle:

796rpm
%CO2: 13.1
%02: 2.1

HC: Max-100 Ave-17 Measured-172!
CO%: Max-1.00 Ave. 0.00 Measured-.63

2470rpm
%CO2: 13.9
%02: 1.3

HC: Max-130 Ave-12 Measured-60
CO%: Max-1.00 Ave. 0.10 Measured-.51


Need help... grrrr
 

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Posted by jaybquick (Member # 4286) on :
 
you have when you need catalytic converters to work well, they need, O2, CO and HC. You have all 3 man. Thay are just up a little too. How old are the cats in your H-pipe. I bet they are going south. A new set will probably get the CO2% up over 14 which shows a good burn. My bet is weak cats unless they are new.
 

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Posted by 94Blackout (Member # 2541) on :
 

quote:

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Originally posted by jaybquick:
you have when you need catalytic converters to work well, they need, O2, CO and HC. You have all 3 man. Thay are just up a little too. How old are the cats in your H-pipe. I bet they are going south. A new set will probably get the CO2% up over 14 which shows a good burn. My bet is weak cats unless they are new.

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