[CA emissions]Need a hand
Thread Starter
Le Mans Master
Joined: Jun 2005
Posts: 5,037
Likes: 520
From: Texas
[CA emissions]Need a hand
Just got back from the smog shop. Damn am I glad I did a pre-inspection. My hydrocarbons are way high (20x more than it was two years ago when I bought it) and oxides of nitrogen were out of spec (15% higher than two years ago). CO was the same.
According to a web search, I found that high HC are due to misfire and that probable cause is wires/plugs. However, it does say that this would also cause CO to be high, which it isnt. Hmm.
Things that have happened in the last two years: did a complete fuel system cleaning, a PCMforless tune, and IAC cleaning. Just noticed that the timing back in '04 was 6 BTDC whereas the timing now is 9 BTDC. The numbers:
2 years ago:
Now:
I know the PCMforless guys hang out around here but I dont know their forum names. If you know them, can you direct them here? I am not positive that its the tune; however, the list of changes are short. I want to make sure it 100% cant be the tune before ripping my car apart and find nothing.
Also, if you guys have some ideas, please post them. Thanks in advance.
According to a web search, I found that high HC are due to misfire and that probable cause is wires/plugs. However, it does say that this would also cause CO to be high, which it isnt. Hmm.
Things that have happened in the last two years: did a complete fuel system cleaning, a PCMforless tune, and IAC cleaning. Just noticed that the timing back in '04 was 6 BTDC whereas the timing now is 9 BTDC. The numbers:
2 years ago:
Now:
I know the PCMforless guys hang out around here but I dont know their forum names. If you know them, can you direct them here? I am not positive that its the tune; however, the list of changes are short. I want to make sure it 100% cant be the tune before ripping my car apart and find nothing.
Also, if you guys have some ideas, please post them. Thanks in advance.
Last edited by Performance nut; Mar 23, 2006 at 09:31 PM.
Burning Brakes
Joined: Jun 2002
Posts: 838
Likes: 0
From: Redding CA
Does the car not have any cats? Man thats a huge change.On my 87 I ran it through a pre check before I put my main cat on, the pre cats are gutted, and it was about like yours. I put the main cat back on (OEM) and it blew as clean as could be.Oops just took a look at your profile, was the car set up the same way in 04?
Last edited by kabnvtt; Mar 23, 2006 at 09:23 PM.
Thread Starter
Le Mans Master
Joined: Jun 2005
Posts: 5,037
Likes: 520
From: Texas
kabnvtt: Same setup, the only changes were those listed above. Just noticed the timing difference; however, I seriously doubt that would cause all this trouble.
Insane1: The headers, which were covered by an EO number in 2004 but due to a change, it is no longer listed. I plan to fight this; however, I have no leg to stand on until I can get the numbers back into spec.
Insane1: The headers, which were covered by an EO number in 2004 but due to a change, it is no longer listed. I plan to fight this; however, I have no leg to stand on until I can get the numbers back into spec.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Retard the timing back, it helps, but won't get you there.
I'd replace the ignition parts, toss in a clean air filter, and put some dry gas in a low tank just before smog.
What's that "MODIFIED" in the smog item list? What does that mean exactly?
I'd replace the ignition parts, toss in a clean air filter, and put some dry gas in a low tank just before smog.
What's that "MODIFIED" in the smog item list? What does that mean exactly?
Thread Starter
Le Mans Master
Joined: Jun 2005
Posts: 5,037
Likes: 520
From: Texas
Modified=headers which were covered by EO # when I bought it but are no longer covered due to change in EO.
Alvin, glad to hear it. I doubted it since we discussed this when I ordered my chip. Had to make sure though. Thanks.
From what I understand, high HC's mean unburnt fuel. Is this the right train of thought?
Alvin, glad to hear it. I doubted it since we discussed this when I ordered my chip. Had to make sure though. Thanks.
From what I understand, high HC's mean unburnt fuel. Is this the right train of thought?
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Brett Foote
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
I am on the fresh tune idea...
new plugs/wires could go a long way to fixing this.
make sure the engine is fully warmed up, too.
take a rubber mallet to the cats... if you hear **** rattling, then you have a cat problem.
check for codes... never know what is lurking in there.
new plugs/wires could go a long way to fixing this.
make sure the engine is fully warmed up, too.
take a rubber mallet to the cats... if you hear **** rattling, then you have a cat problem.
check for codes... never know what is lurking in there.
Thread Starter
Le Mans Master
Joined: Jun 2005
Posts: 5,037
Likes: 520
From: Texas
Originally Posted by Alvin
yes, usually high HC's and low CO is a misfire. I would go back and put new plugs, cap/rotor/ wires on the car. It could probally stand to have a fresh tune up anyway.
How about the high NOx? I read a post about checking the EGR side of things for leaks. Any other suggestions/possible causes?
Thread Starter
Le Mans Master
Joined: Jun 2005
Posts: 5,037
Likes: 520
From: Texas
Originally Posted by bogus
I am on the fresh tune idea...
new plugs/wires could go a long way to fixing this.
make sure the engine is fully warmed up, too.
take a rubber mallet to the cats... if you hear **** rattling, then you have a cat problem.
check for codes... never know what is lurking in there.
new plugs/wires could go a long way to fixing this.
make sure the engine is fully warmed up, too.
take a rubber mallet to the cats... if you hear **** rattling, then you have a cat problem.
check for codes... never know what is lurking in there.
As for the mallet, I will give it a shot. Though, I might be tempted to misuse the mallet if it fails again.
Le Mans Master
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
Iam with alvin, before modding my car i failed GA emmission than i did full tune up plugs, wire, oil change, cap & rotor along with new coil n distributor module, passed emmission like pulling hair from a hot cheese...u need tune my friend with AC delco stock stuff no need of MSD or accel.....heck my car passes emmission even with cam/head/LT headers with Alvin's tune...
Race Director
Joined: Sep 2005
Posts: 13,269
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From: Sharpsburg Georgia
GA Events Coordinator
From looking at your #'s i would agree that i would start with a good tune up first, and like "sami85l98" said do a oil change, this is something that a lot of people overlook when trying to repair a emm problem.
You might want to look at the "swing" on your O2's and make sure they are switching back and forth like they should.
With #'s like you have, if it is not your tune i would check your cat and make sure it is lighting off, ie hotter in the back than it is in the front.
Greg N
You might want to look at the "swing" on your O2's and make sure they are switching back and forth like they should.
With #'s like you have, if it is not your tune i would check your cat and make sure it is lighting off, ie hotter in the back than it is in the front.
Greg N
Thread Starter
Le Mans Master
Joined: Jun 2005
Posts: 5,037
Likes: 520
From: Texas
Originally Posted by blown87
You might want to look at the "swing" on your O2's and make sure they are switching back and forth like they should.
Greg N
Greg N
Race Director
Joined: Sep 2005
Posts: 13,269
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From: Sharpsburg Georgia
GA Events Coordinator
The O2 sensors can be checked by using a digital voltmeter, you are looking for a fairly rapid voltage change between about .300 mv to about .800 mv.
The best way to do this is with a scan tool, IMHO.
The best way to do this is with a scan tool, IMHO.
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
I had a "91" Camaro which passed Ca smog with flying colors the year I bought it, then two years later after I installed an SLP y-pipe, random-tech cat and flowmaster exhaust, the engine failed the smog test with high HC and Nox.
I took my Camaro to a very knowledgable mechanic and he said the engine had a lack of backpressure which the EGR needed to function correctly and it also, had a lean misfire. I finally had a stock cat installed, increased the fuel pressure and retarded the timing 3 degrees to finally barely pass ($600 later).
I vowed then to leave all parts from the Cat forward, stock. California emissions testing is rough.
I took my Camaro to a very knowledgable mechanic and he said the engine had a lack of backpressure which the EGR needed to function correctly and it also, had a lean misfire. I finally had a stock cat installed, increased the fuel pressure and retarded the timing 3 degrees to finally barely pass ($600 later).
I vowed then to leave all parts from the Cat forward, stock. California emissions testing is rough.
