Vette failed smog
Thread Starter
Racer
Joined: May 2009
Posts: 364
Likes: 3
From: merced ca
Vette failed smog
Ok after 2 years of my car being down for restoring it. I took it to get smogged yesterday. Well it failed on the HC on low speed. Stupid me rembered that the ECM needs to relearn if the car had no power. So I drove it for a bit yesterday. And yeah forgot to check tire pressure too, doh! I have one day left on my moving permit and I have a free retest. Really don't want to waste it. Does anyone think that my problem could have been the fact that I didn't give the ECM enough time to relearn. Maybe even drive about 5-10 miles before getting it smogged. I live in cali and any suggestions would be helpful. And it's an 89 vette L98
Burning Brakes
Joined: Aug 2006
Posts: 878
Likes: 2
From: BC
HC's are caused by unburnt fuel. If that's the only think you failed on I would guess at an Incomplete burn / misfire.
How does it sound? Any hint of a misfire? Checked the timing at all?
The hotter you get that CAT before the retest the better. Some good hard pulls are needed to get them working at their best.
How does it sound? Any hint of a misfire? Checked the timing at all?
The hotter you get that CAT before the retest the better. Some good hard pulls are needed to get them working at their best.
Thread Starter
Racer
Joined: May 2009
Posts: 364
Likes: 3
From: merced ca
Ok so decided to check my timing and tps voltage. Timing was at 4 and tps was at .49. So put timing back to 6 and did the whole base idle tps procedure. Swear I did all this before a long time ago, but whatever did again. seems to be running even better and my gas milage is running higher on the instant mpg. So haven't done the test yet going to wait until Monday. That and my dad wants to check my cats with his temp gun.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
High hydrocarbon (HC) readings usually indicate excessive unburned fuel caused by a lack of ignition or by incomplete combustion. Concentrations are measured in parts per million (PPM). Common causes include a faulty ignition system, vacuum leaks, and fuel mixture problems. Circumstances that can lead to a high HC emissions are:
* Incomplete combustion due to fouled spark plugs.
* Improper timing or dwell
* Damaged ignition wires
* Poor compression
* Vacuum leak
* Ineffective or faulty air management system (ECM control of air/fuel ratios)
* Catalytic converter intervention and HC concentrations
High HC readings at the tailpipe are a clear indication that there is a problem in at least one part of the system, but an HC reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance. HC readings at or near "normal" are possible, and not uncommon.
* Incomplete combustion due to fouled spark plugs.
* Improper timing or dwell
* Damaged ignition wires
* Poor compression
* Vacuum leak
* Ineffective or faulty air management system (ECM control of air/fuel ratios)
* Catalytic converter intervention and HC concentrations
High HC readings at the tailpipe are a clear indication that there is a problem in at least one part of the system, but an HC reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance. HC readings at or near "normal" are possible, and not uncommon.
Burning Brakes
Joined: Nov 2009
Posts: 828
Likes: 103
From: Olney MD
Emissions test
I was in your shoes a couple of months ago. My emissions were 10 times the legal limit.
I filled up with regular (to retard the spark a little) and drove it until it was down to about 5 gallons of gas. then I added a gallon of denatured alcohol and took it for the emissions test. Result- passed with flying colors. I didnt think it was true (read it on the internet) but it worked for me!!
Good luck!
I filled up with regular (to retard the spark a little) and drove it until it was down to about 5 gallons of gas. then I added a gallon of denatured alcohol and took it for the emissions test. Result- passed with flying colors. I didnt think it was true (read it on the internet) but it worked for me!!
Good luck!
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Those machines can tell if fuel has been diluted.
read about one or two it worked for and know a few that were pizzed it did nothing now they are classified as "gross poluters"
Fix your problem the car will run much better when all is right.
read about one or two it worked for and know a few that were pizzed it did nothing now they are classified as "gross poluters"
Fix your problem the car will run much better when all is right.
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Thread Starter
Racer
Joined: May 2009
Posts: 364
Likes: 3
From: merced ca
http://www.flickr.com/photos/83257995@N04/7626855546/
Heres a link for my smog test. I cant seem to upload on the forum.
Heres a link for my smog test. I cant seem to upload on the forum.
Last edited by kitttransam; Jul 22, 2012 at 11:04 PM. Reason: add more
Thread Starter
Racer
Joined: May 2009
Posts: 364
Likes: 3
From: merced ca
my dad came by to check it out. he used to be a smog tech and did alot of diagnostics on cars.He checked the temps of the cats as I had the motor at 2500 rpms. The passenger side cat was cooler then the driver side. I don't like making myself look bad but 3 years ago when I rebuilt the motor I had 2 plug wires crossed on the passenger side. That cat ran really hot. even burnt the carpet on that side. So he thinks that the heat probably damaged that cat and it probably needs to be replaced. And yeah he knows the smell of the exhaust when a motor runs lean. He said he could smell it running lean.
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
my dad came by to check it out. he used to be a smog tech and did alot of diagnostics on cars.He checked the temps of the cats as I had the motor at 2500 rpms. The passenger side cat was cooler then the driver side. I don't like making myself look bad but 3 years ago when I rebuilt the motor I had 2 plug wires crossed on the passenger side. That cat ran really hot. even burnt the carpet on that side. So he thinks that the heat probably damaged that cat and it probably needs to be replaced. And yeah he knows the smell of the exhaust when a motor runs lean. He said he could smell it running lean.
This is the best deal I've found so far on a legal, catted Y-pipe for CA cars:
http://www.ebay.com/itm/260857465714...84.m1438.l2649
Hope that helps!
Thread Starter
Racer
Joined: May 2009
Posts: 364
Likes: 3
From: merced ca
Oreillys has it for $276. Although thinking about just having an exhaust shop replace the one side. I'd rather do both but my budget is extremely tight right now. Although I didn't drive very much before the test. Maybe a mile in the freeway then a little city driving. I did make adjustments after the test. Timing and base idle and tps. They were all off. And my milage increased. Wondering if that could've helped my problem before I get a cat. I got one free retest and I really hate to waste it.
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
Oreillys has it for $276. Although thinking about just having an exhaust shop replace the one side. I'd rather do both but my budget is extremely tight right now. Although I didn't drive very much before the test. Maybe a mile in the freeway then a little city driving. I did make adjustments after the test. Timing and base idle and tps. They were all off. And my milage increased. Wondering if that could've helped my problem before I get a cat. I got one free retest and I really hate to waste it.
Drifting
Joined: Jun 2002
Posts: 1,945
Likes: 41
From: Corinth TX
Well I am going to jump on the "getting the cats good and hot" bandwagon. I failed on mine a while back when my wife had taken the car to get it inspected. She drove it straight over to the place (about 5 ins away). I had worked graveyards the night before so I was sleeping. The next day I took it for a 20-30 mins spirited drive and then took it to get inspected. Passed with flying colors. Those cats have to get good and hot to work correctly. Good luck and tell everyone how the inspection goes.
Burning Brakes
Joined: Apr 2012
Posts: 888
Likes: 4
From: Ridgecrest Ca
The guy I go to always lets the car idle for at least 15 minutes before he performs the "sniff". I've never had a car fail yet because the cats weren't hot. Small town with more time for the smog guy. Ha Ha. Plus he only charges $45. We don't do the dynos here. If I got an address 5 miles north I wouldn't have to smog at all. Inyo county is one of the 9 in California that doesn't require the testing. Only for a sale of a car.
Thread Starter
Racer
Joined: May 2009
Posts: 364
Likes: 3
From: merced ca
I heard mariposa doesn't require smog either. I live 35 miles from there. I more or less drove straight there to get the test. But there was also 2 cars ahead of me too. So my car just sat while the other cars were getting their test done.