Failed emmissions!
Thread Starter
Pro
Joined: Aug 2012
Posts: 663
Likes: 1
From: Nashville TN
Failed emmissions!
I failed emissions yesterday and am looking for suggestions.
I got a Code 44 left bank lean while idling in the line for an hr. I shut the car off when I got in and restarted it. The light stayed off but came back on when she had the sniffer stuck up my rear.
I got high HC and high CO.
Yesterday afternoon I changed the air filter and added a bottle of Chemtool to the tank. Today the darn light came on again. I just checked for vacuum leaks and cleaned the IAC and butterflies and let it idle for a while and no light.
It smells rich though.
I got a Code 44 left bank lean while idling in the line for an hr. I shut the car off when I got in and restarted it. The light stayed off but came back on when she had the sniffer stuck up my rear.
I got high HC and high CO.
Yesterday afternoon I changed the air filter and added a bottle of Chemtool to the tank. Today the darn light came on again. I just checked for vacuum leaks and cleaned the IAC and butterflies and let it idle for a while and no light.
It smells rich though.
Racer
Joined: Apr 2001
Posts: 349
Likes: 1
From: Clayton CA
With all the idling in your description, it could be O2 sensors or catalytic converters. The cats have to be hot to work properly. The O2 sensors have to be clean. Not sure about chemtool product but some additives aren't friendly to emission readings.
Burning Brakes
Joined: Nov 2009
Posts: 828
Likes: 103
From: Olney MD
Emissions test
I failed emissions this spring. My emissions were 10 times higher than the limit (tail pipe sniffer test).
Here's what i did. I changed from premium to regular grade for a week or so. then I let the gas get down to about a quarter tank, and bought a gallon of denatured alcohol from Lowes, put it in the tank and went back to take a re-test. Passed! Not by much, but it passed! Treated the Corvette to a tankful of high test and haven't had any problems since.
It may not work for you, but for a $14 investment (gallon of alcohol), it can't hurt.
Here's what i did. I changed from premium to regular grade for a week or so. then I let the gas get down to about a quarter tank, and bought a gallon of denatured alcohol from Lowes, put it in the tank and went back to take a re-test. Passed! Not by much, but it passed! Treated the Corvette to a tankful of high test and haven't had any problems since.
It may not work for you, but for a $14 investment (gallon of alcohol), it can't hurt.
Melting Slicks
Joined: Apr 2001
Posts: 2,112
Likes: 220
From: Ca.
I failed emissions yesterday and am looking for suggestions.
I got a Code 44 left bank lean while idling in the line for an hr. I shut the car off when I got in and restarted it. The light stayed off but came back on when she had the sniffer stuck up my rear.
I got high HC and high CO.
Yesterday afternoon I changed the air filter and added a bottle of Chemtool to the tank. Today the darn light came on again. I just checked for vacuum leaks and cleaned the IAC and butterflies and let it idle for a while and no light.
It smells rich though.
I got a Code 44 left bank lean while idling in the line for an hr. I shut the car off when I got in and restarted it. The light stayed off but came back on when she had the sniffer stuck up my rear.
I got high HC and high CO.
Yesterday afternoon I changed the air filter and added a bottle of Chemtool to the tank. Today the darn light came on again. I just checked for vacuum leaks and cleaned the IAC and butterflies and let it idle for a while and no light.
It smells rich though.
However showing lean left bank.....You have an exhaust leak- extra air gets pulled in and gives a false lean to the O2 sensor-computer adds and adds fuel trying to make up for it.
Thread Starter
Pro
Joined: Aug 2012
Posts: 663
Likes: 1
From: Nashville TN
Replaced PCV and hose today and sprayed ether on every vacuum line and connection. No change.
It appears to kick in the SES light with a code 44 as soon as it tried to go into closed loop. Should I just replace this sensor?
It appears to kick in the SES light with a code 44 as soon as it tried to go into closed loop. Should I just replace this sensor?
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
I failed emissions this spring. My emissions were 10 times higher than the limit (tail pipe sniffer test).
Here's what i did. I changed from premium to regular grade for a week or so. then I let the gas get down to about a quarter tank, and bought a gallon of denatured alcohol from Lowes, put it in the tank and went back to take a re-test. Passed! Not by much, but it passed! Treated the Corvette to a tankful of high test and haven't had any problems since.
It may not work for you, but for a $14 investment (gallon of alcohol), it can't hurt.
Here's what i did. I changed from premium to regular grade for a week or so. then I let the gas get down to about a quarter tank, and bought a gallon of denatured alcohol from Lowes, put it in the tank and went back to take a re-test. Passed! Not by much, but it passed! Treated the Corvette to a tankful of high test and haven't had any problems since.
It may not work for you, but for a $14 investment (gallon of alcohol), it can't hurt.
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Melting Slicks
Joined: Aug 2008
Posts: 2,082
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From: Palmdale CA
Team Owner
Joined: Jul 2004
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From: Hartford WI
Thread Starter
Pro
Joined: Aug 2012
Posts: 663
Likes: 1
From: Nashville TN
I pulled a plug on the left side and it was pretty black, not what I expected. I pulled the O2 sensor which came right out and it too was black.. I cleaned it up and put it back and got the same 44 code.
Advanced
Joined: Jul 2012
Posts: 83
Likes: 0
I had a similar code. Bad O2 sensor was the culprit.
It had the ECM correcting what was sensed as a lean condition and it was dumping fuel in to compensate. I had the fuel smell, too, like it was running very rich.
A new O2 sensor, not simply a cleaned one, and I was on my way. These cause so many issues when they fail and running rich is a typical symptom.
Just a suggestion and it isn't too expensive.
It had the ECM correcting what was sensed as a lean condition and it was dumping fuel in to compensate. I had the fuel smell, too, like it was running very rich.
A new O2 sensor, not simply a cleaned one, and I was on my way. These cause so many issues when they fail and running rich is a typical symptom.
Just a suggestion and it isn't too expensive.
Thread Starter
Pro
Joined: Aug 2012
Posts: 663
Likes: 1
From: Nashville TN
I had a similar code. Bad O2 sensor was the culprit.
It had the ECM correcting what was sensed as a lean condition and it was dumping fuel in to compensate. I had the fuel smell, too, like it was running very rich.
A new O2 sensor, not simply a cleaned one, and I was on my way. These cause so many issues when they fail and running rich is a typical symptom.
Just a suggestion and it isn't too expensive.
It had the ECM correcting what was sensed as a lean condition and it was dumping fuel in to compensate. I had the fuel smell, too, like it was running very rich.
A new O2 sensor, not simply a cleaned one, and I was on my way. These cause so many issues when they fail and running rich is a typical symptom.
Just a suggestion and it isn't too expensive.
Advanced
Joined: Jul 2012
Posts: 83
Likes: 0
I actually had this happen twice. A '91 350 TBI pickup that I had for years also threw a lean code, and again it was the sensor.
On the '92 LT1, I replaced both sensors since I was already working on the car.
They screw in to the sensor bung sort of like a spark plug. Unfortunately, they have a wire coming out of them, so a standard socket won't go over them.
On the truck I was able to use an open end wrench and on the Vette I used a crows foot socket. Both times I sprayed some PB Blaster penetrating oil on it to get it loose. I cleaned that up real well before I put in a new one. I would think it's not good for the sensor.
Open end wrench, crows foot socket or one of the actual sensor sockets should work if you have the room to work on it.
On the '92 LT1, I replaced both sensors since I was already working on the car.
They screw in to the sensor bung sort of like a spark plug. Unfortunately, they have a wire coming out of them, so a standard socket won't go over them.
On the truck I was able to use an open end wrench and on the Vette I used a crows foot socket. Both times I sprayed some PB Blaster penetrating oil on it to get it loose. I cleaned that up real well before I put in a new one. I would think it's not good for the sensor.
Open end wrench, crows foot socket or one of the actual sensor sockets should work if you have the room to work on it.
Thread Starter
Pro
Joined: Aug 2012
Posts: 663
Likes: 1
From: Nashville TN
I changed O2 sensors today. I took the car for a spin and it ran strong. Feels like an LT1 and not a tuned port now.
I spent about an hr some of which was in heavy traffic and did not get a check engine light.
I'll get it back to the emissions center this week
I spent about an hr some of which was in heavy traffic and did not get a check engine light.
I'll get it back to the emissions center this week
Last edited by bassackwards; Oct 7, 2013 at 07:34 PM.
Burning Brakes
Joined: Nov 2009
Posts: 828
Likes: 103
From: Olney MD
Emissions test
I made sure to go and fill the tank right away with real gas! Alcohol isnt quite like acid- it takes a while of using it to do damage. The crazy thing is that i had passed emissions with no trouble two years earlier, and hadn't done anything to change the 'tune' on the engine.
In any case, pretty soon the alcohol was very diluted and passed through the engine. I didn't want to take any chances on damaging my fuel system.
