failed due to High HC, everything else was fine.............

[NCC1701]

I just failed due to high HC.
My DP to cat connection was loose so I had a major leak there during the test. Found this out when I pulled the cat to make sure the element inside wasn't cracked or damaged. Once I loosened the four bolts at rear of the cat, I could just pull the cat off the DP. I also need to fix the end of my dp it is definatly out of round. Would a big leak there cause High HC?
I am going to fix that before the retest.
I also replaced plug and wires, but the old plugs all looked good and showed no sign of a missfire. I put the factory intake on.
my HC were
15mph 96 max is 77
25mph 99 max is 59
everything else was well below limits.
CO
15mph .07 max is .50
25mph .06 max is .41
NO
15mph 187 max is 541
25 mph 147 max is 498
%CO
15mph 14.6
25mph 14.7
%O2
15mph .4
25mph .4
Any thoughts or suggestions?
TIA
Lorenzo
AKA
Ncc1701

 

[charlief1]

If you have a full tank throw a few gallons of either alky or E-85 in it and try it again. The cat may not have gotten hot enough either so you might try driving it some and see if helps.

 

[Fast4Ward]

was my post way too off topic...lol...i'm hoping for a retest tomorrow.

 

[NCC1701]

UPDATE
I just passed but barely.
MY HC are were right at the max numbers.
my HC were
15mph 77 max is 77
25mph 59 max is 59
everything else was well below limits.
CO
15mph .15 max is .50
25mph .11 max is .41
NO
15mph 82 max is 541
25 mph 75 max is 498
%CO
15mph 14.7
25mph 14.8
%O2
15mph .1
25mph .1

What I did since last test was to add new plugs and wires, cleaned PCV Valve resecured Cat to Downpipe tightly.
I am still wondering why my HC are still borderline with the emission chip? I know I have a pretty good exhaust leak at the drivers side crossover, would that contribute to my high HC?
TIA
Lorenzo

 

[charlief1]

The leak in the crossover is why you have the high HC level. The O2 sensor is reading it as a lean condition so it the puter is adding fuel to compensate.

 

[bison]

The leak in the crossover is why you have the high HC level. The O2 sensor is reading it as a lean condition so it the puter is adding fuel to compensate.

Probably not since CO did not increase and always does if its rich. Id retard the timing and get the cat converter as hot as i could.

 

[NCC1701]

This is what is so frustrating about the smog check out here in California. You cannot measure your emissions to know if your adjustments made a difference or not. You have to go pay $50 or $60 dollars and then sweat bullets until it passes,if your lucky. If it fails, well, you just have to try something else and pay the testing fee again
I will have the crossover leak fixed before test in 2013 and I will retard the timing before I go in next time. I am putting this note with my smog chip
Other than that, It runs great.
TIA
Lorenzo

 

[gofstbuick]

Aftermarket PCV valve or delco? Your emissions chip may have pushed emissions to lean misfire, because NOx looks excessively low

 

[TurboDave]

Excuse the question, but how are you going to adjust timing???? Since all chips that I know about, the "base" timing (that part of timing that is used under test conditions) is in a fixed table, and the only adjustments available in chips for timing is the WOT part of the timing.

 

[NCC1701]

Will check PCV this evening......

I was under the impression that you could adjust base timimg with the Transplus I could be mistaken in thinking that. I remember way back when I upgraded to the Trans plus it ran so well with the basic adjustment, I never had to chance to mess with adjusting the parameters. Set and forget it
I am very curious as the smog shop owner said they are always making the standards tighter for passing.
On the PCV, I did notice that the hose leading up to the hard line on the Vacuum block was cracked due to age. Would that have contributed to my High HC condition?
I want to have my best shot at passing in 2013:biggrin:
What can I do about the lean misfire? I thought the Turbotweak emission chip was basically a stock chip burned for the bigger injectors
TIA
Lorenzo

 

[NCC1701]

PCV is AC Delco. I knew I followed the suggestions here when I got it

 

[turbocamino1]

"failed due to High HC, everything else was fine".............2 gal e-85 to 10gal gas always put my HC's just below limits. Erics emission chip can work wonders too (turns fan on latter to keep combustion hot..lower f/press and timing too) for 50 bucks, well worth having. His street chip effects several other peramiters as well for great street manners....money well spent also.