Failed smog today.. What should i do guys?
#1
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Failed smog today.. What should i do guys?
Before i dove into the forced inducted world i figured ide get my car smoged since i had another 4 week to complete it. I put the stock AFM, ecu and air filter all back on. Figured ide by just fine, however that is not the case.
During the 15 and 25 mph driving on the machine my No(PPM) numbers were a bit too high. The average at 15 mph is 237 and the max is 847 while my 90 did 989 and at 25 mph the average is 199 max is 786 while my numbers were at a high of 953.
The tech said it was most likely my cat causing the high numbers and stated that on a personal level i should possibly retard the timing, get a new cat and run 91 fuel.
It has stock header/cat (original 106k miles) and a magnaflow muffler. The timing is advanced to 14 degrees while on the stock ecu.
For those of you who have failed smog what have you done to fix it?
Thanks all
During the 15 and 25 mph driving on the machine my No(PPM) numbers were a bit too high. The average at 15 mph is 237 and the max is 847 while my 90 did 989 and at 25 mph the average is 199 max is 786 while my numbers were at a high of 953.
The tech said it was most likely my cat causing the high numbers and stated that on a personal level i should possibly retard the timing, get a new cat and run 91 fuel.
It has stock header/cat (original 106k miles) and a magnaflow muffler. The timing is advanced to 14 degrees while on the stock ecu.
For those of you who have failed smog what have you done to fix it?
Thanks all
#3
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I was thinking of throwing the megasquirt back in and tuning it a bit richer in the "15 mph and 25 mph" zones and giving it another shot. What is your guy's suggestion on my timing map, throw it all into 10 degrees just to be safe?
#7
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Brainey's right. All else being equal, high NOx is a byproduct of increased in-cylinder temp / pressure, which can be indicative of a lean mixture or overly advanced timing. Since we know your timing is too advanced, dial it back to maybe 8 degrees BTDC at warm idle with the TEN-GND jumper. 91 octane will also slow the burn a little and should help NOx as well.
What were your HC and CO numbers? Those will give us an indication as to how the mixture is running.
Some helpful info: http://www.firstfives.org/faq/smog/smog_faq.html
What were your HC and CO numbers? Those will give us an indication as to how the mixture is running.
Some helpful info: http://www.firstfives.org/faq/smog/smog_faq.html
#8
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My hc numbers were as follows:
15 mph was @ 63 w/ a max of 134 and average of 31
25 mph was @ 56 w/ a max of 108 and an average of 20
CO numbers were as follows:
15 mph was @ .17 with a max of .82 and an average of .1
25 mph was @ .19 with a max of .71 and an average of .09
Ill manually retard the timing to 8* BTDC and go in for a re test tomorrow afternoon, thanks all
Edit: Cat was hot, well it idled for about 3 min before getting put to the test after a 10 min drive to the local test only station.
15 mph was @ 63 w/ a max of 134 and average of 31
25 mph was @ 56 w/ a max of 108 and an average of 20
CO numbers were as follows:
15 mph was @ .17 with a max of .82 and an average of .1
25 mph was @ .19 with a max of .71 and an average of .09
Ill manually retard the timing to 8* BTDC and go in for a re test tomorrow afternoon, thanks all
Edit: Cat was hot, well it idled for about 3 min before getting put to the test after a 10 min drive to the local test only station.
Last edited by thesnowboarder; 04-30-2008 at 08:40 PM.
#10
Boost Pope
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Hmmmm. Based on the HC numbers you're not running ultra-lean, so I'm thinking it's either the timing, or the cat is on its way out.
Retarding the timing should help, a tankful of 91/93 octane fuel might also add a slight edge.
Retarding the timing should help, a tankful of 91/93 octane fuel might also add a slight edge.
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