I also failed smog test HELP
Thread Starter
Burning Brakes
Joined: Feb 2010
Posts: 1,013
Likes: 2
From: California City Ca
I also failed smog test HELP
I tried to pass California smog today it failed The smog technician said it runs lean at Idle but still passes there but a cruise it fails it too rich at 2500 RPM’s.
He said it could be my fuel regulator When I got home I hooked up my pressure gauge reads 40 PSI at Idle 38 PSI at 2500 RPM’s.
Here a copy of the Smog read out Can someone help me figure this out so I can get it pass smog.
He said it could be my fuel regulator When I got home I hooked up my pressure gauge reads 40 PSI at Idle 38 PSI at 2500 RPM’s.
Here a copy of the Smog read out Can someone help me figure this out so I can get it pass smog.
Last edited by Marv02; Jan 21, 2012 at 08:59 PM.
Safety Car
Joined: Aug 2009
Posts: 3,745
Likes: 275
From: Melbourne, Victoria, Australia
[QUOTE=Marv02;1579799417]I tried to pass California smog today it failed The smog technician said it runs lean at Idle but still passes there but a cruise it fails it too rich at 2500 RPM’s.
He said it could be my fuel regulator When I got home I hooked up my pressure gauge reads 40 PSI at Idle 38 PSI at 2500 RPM’s.
Here a copy of the Smog read out Can someone help me figure this out so I can get it pass smog.
Hi standard fuel pressure should be around 30 to 32 psi.
that is what my 85 vette had. I have since put an adjustable fuel pressure regulator on and yes it does run richer at the 45 psi i have set it to.
Would be great if someone made an adjustable fuel pressure regulator with a ''performance'' and ''emission testing'' marks on it
He said it could be my fuel regulator When I got home I hooked up my pressure gauge reads 40 PSI at Idle 38 PSI at 2500 RPM’s.
Here a copy of the Smog read out Can someone help me figure this out so I can get it pass smog.
Hi standard fuel pressure should be around 30 to 32 psi.
that is what my 85 vette had. I have since put an adjustable fuel pressure regulator on and yes it does run richer at the 45 psi i have set it to.
Would be great if someone made an adjustable fuel pressure regulator with a ''performance'' and ''emission testing'' marks on it
Safety Car
Joined: Aug 2009
Posts: 3,745
Likes: 275
From: Melbourne, Victoria, Australia
Hi
My vette had 30-32 psi fuel pressure standard, this is one of the first mods people do is raise the fuel pressure.
More pressure helps with a better spray pattern and getting more fuel thru the injectors, this in turn gives a slight performance increase but can also make you fail emissions. 40 to 45 psi the TPI engines like.
the fuel pressure regulator has a spring that keeps the pressure in the low 30 psi range. It does this by bypassing excess fuel to the tank.
The adjustable type have a screw to adjust the pressure.
To locate the fuel pressure regulator follow the vacuum hose from the side of the inlet manifold one leads to the regulator, if it is flat on top it is standard and if there is a screw in the middle it is adjustable . See link below to see what the standard one looks like.
http://www.parts123.com/parts123/yb....5Z5Z50000050F#
If you have an adjustable fuel pressure regulator you can turn it anti clockwise to reduce the pressure and pass the test
Hope this helps you
My vette had 30-32 psi fuel pressure standard, this is one of the first mods people do is raise the fuel pressure.
More pressure helps with a better spray pattern and getting more fuel thru the injectors, this in turn gives a slight performance increase but can also make you fail emissions. 40 to 45 psi the TPI engines like.
the fuel pressure regulator has a spring that keeps the pressure in the low 30 psi range. It does this by bypassing excess fuel to the tank.
The adjustable type have a screw to adjust the pressure.
To locate the fuel pressure regulator follow the vacuum hose from the side of the inlet manifold one leads to the regulator, if it is flat on top it is standard and if there is a screw in the middle it is adjustable . See link below to see what the standard one looks like.
http://www.parts123.com/parts123/yb....5Z5Z50000050F#
If you have an adjustable fuel pressure regulator you can turn it anti clockwise to reduce the pressure and pass the test
Hope this helps you
Thread Starter
Burning Brakes
Joined: Feb 2010
Posts: 1,013
Likes: 2
From: California City Ca
I made my adjustable long time ago I back iit off and see what happens.
Hi
My vette had 30-32 psi fuel pressure standard, this is one of the first mods people do is raise the fuel pressure.
More pressure helps with a better spray pattern and getting more fuel thru the injectors, this in turn gives a slight performance increase but can also make you fail emissions. 40 to 45 psi the TPI engines like.
the fuel pressure regulator has a spring that keeps the pressure in the low 30 psi range. It does this by bypassing excess fuel to the tank.
The adjustable type have a screw to adjust the pressure.
To locate the fuel pressure regulator follow the vacuum hose from the side of the inlet manifold one leads to the regulator, if it is flat on top it is standard and if there is a screw in the middle it is adjustable . See link below to see what the standard one looks like.
http://www.parts123.com/parts123/yb....5Z5Z50000050F#
If you have an adjustable fuel pressure regulator you can turn it anti clockwise to reduce the pressure and pass the test
Hope this helps you
My vette had 30-32 psi fuel pressure standard, this is one of the first mods people do is raise the fuel pressure.
More pressure helps with a better spray pattern and getting more fuel thru the injectors, this in turn gives a slight performance increase but can also make you fail emissions. 40 to 45 psi the TPI engines like.
the fuel pressure regulator has a spring that keeps the pressure in the low 30 psi range. It does this by bypassing excess fuel to the tank.
The adjustable type have a screw to adjust the pressure.
To locate the fuel pressure regulator follow the vacuum hose from the side of the inlet manifold one leads to the regulator, if it is flat on top it is standard and if there is a screw in the middle it is adjustable . See link below to see what the standard one looks like.
http://www.parts123.com/parts123/yb....5Z5Z50000050F#
If you have an adjustable fuel pressure regulator you can turn it anti clockwise to reduce the pressure and pass the test
Hope this helps you
Safety Car
Joined: Aug 2009
Posts: 3,745
Likes: 275
From: Melbourne, Victoria, Australia
Ok that should help you
i know that my vette loves the 45- 50 psi but man it does run very rich you can feel your eyes sting from the exhaust fumes.
You just need to remember to back the fuel pressure off and leave it at the low 30 psi mark for the emissions testing, then crank it up afterwards
Also check your throttle position sensor (top and middle wires) 0.54vdc at idle, that is used by the ecm to calculate fuel delivery also.
I am glad Australia doesn't have emissions testings every year
i know that my vette loves the 45- 50 psi but man it does run very rich you can feel your eyes sting from the exhaust fumes.
You just need to remember to back the fuel pressure off and leave it at the low 30 psi mark for the emissions testing, then crank it up afterwards
Also check your throttle position sensor (top and middle wires) 0.54vdc at idle, that is used by the ecm to calculate fuel delivery also.I am glad Australia doesn't have emissions testings every year
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Melting Slicks
Joined: Jun 2004
Posts: 3,253
Likes: 2
From: Castro Valley CA
Do a pretest($25) to see if the mod worked first before you run the official smog, otherwise you might tagged as a gross polluter(further bureaucratic BS and money.) Your HC is low, so your Cat seems to be good. Good luck, its a fricken hassle with the State on this chit for a car you probably don't even drive 5,000 miles a year.
http://www.smogtips.com/failed-high-...onoxide-CO.cfm
http://www.smogtips.com/failed-high-...onoxide-CO.cfm
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
It would seem that if the engine was under a load the Cat's would run a-little hotter, and further reduce the Carbon Monoxides (CO).
Bottom line is...the O2 to fuel ratio is off a bit, or the Cats aren't doing their job.
The ECM will adjust the injector dwell time based on data input from what ever sensors the ECM Utilizes: i.e. MAP, MAFF, TPS, O2 etc. so if one of these sensors is biased this could effect the fuel/air ratio.
http://auto.howstuffworks.com/catalytic-converter2.htm
Thread Starter
Burning Brakes
Joined: Feb 2010
Posts: 1,013
Likes: 2
From: California City Ca
The Cat is New the O2 is new everything just about new in the car I am going to try the race gas and the alcohol trick next I hope this works.
interesting...I havent seen a 2500 RPM test done "static" in years, typically the car is first Weighed and then spun up on the rollers for this test. This more closely simulates real driving conditions.
It would seem that if the engine was under a load the Cat's would run a-little hotter, and further reduce the Carbon Monoxides (CO).
Bottom line is...the O2 to fuel ratio is off a bit, or the Cats aren't doing their job.
The ECM will adjust the injector dwell time based on data input from what ever sensors the ECM Utilizes: i.e. MAP, MAFF, TPS, O2 etc. so if one of these sensors is biased this could effect the fuel/air ratio.
http://auto.howstuffworks.com/catalytic-converter2.htm
It would seem that if the engine was under a load the Cat's would run a-little hotter, and further reduce the Carbon Monoxides (CO).
Bottom line is...the O2 to fuel ratio is off a bit, or the Cats aren't doing their job.
The ECM will adjust the injector dwell time based on data input from what ever sensors the ECM Utilizes: i.e. MAP, MAFF, TPS, O2 etc. so if one of these sensors is biased this could effect the fuel/air ratio.
http://auto.howstuffworks.com/catalytic-converter2.htm
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
You need to find out just how the technician ran the test...I had a 98 Malibu that had failed the test several years ago, and it turned out that the tech was "Manually" shifting gears
I instructed him to allow the TCM to do the shifting, and not to Hold the tranny in a gear of his choice, and the test "Passed"Of course he couldn't believe the results, Because something like this had never happend before.
Melting Slicks
Joined: Jun 2004
Posts: 3,253
Likes: 2
From: Castro Valley CA
BAR sets the parameters of the test when the technician uploads with their computer; its not at the discretion of the smog tech. My 2000 Mercedes C280 had the test done statically, yet my 2000 Saturn and 1994 LT1 Corvette were spun up on the rollers. Full time 4WD's are done statically for obvious reasons. It doesn't make any sense to me. They didn't even monitor NOX on his.
Instructor
Joined: Aug 2010
Posts: 238
Likes: 0
From: Asheboro North Carolina
We don't have emission testing in NC so I don't have personal experience with which to prove one way or another, but I have used Amsoil P.I. in my 95 with good results. It would be interesting to see what your test results would be if you ran a tankful with this additive before going back.
http://www.amsoil.com/storefront/api.aspx
Of course you could always move.
http://www.amsoil.com/storefront/api.aspx
Of course you could always move.
Last edited by hogsnvettes; Jan 22, 2012 at 01:45 PM. Reason: added comment
Melting Slicks
Joined: Jan 2009
Posts: 3,482
Likes: 195
From: folsom california
high CO could be the result of too much fuel and not enough air resulting in incomplete combustion (too rich) or too little fuel and too much air resulting in incomlete combustion (too lean).
in either case the test is simple; run the engine and bleed in some propane gas from a handheld bottom; if your engine has a too rich condition, the readings will get worse; if the engine is running too lean, the readings will get better.
based on my personal experience, an engine of mine which failed, and I assumed to be running too rich, was in fact proved by the above test to be running too lean.
Sounds like y0ur fuel pressures might be a little low, and if it was running lean at idle (as the smog tech said), I would suspect that it was also lean under load. Try the above test; it will help you with a definitive diagnosis.
in either case the test is simple; run the engine and bleed in some propane gas from a handheld bottom; if your engine has a too rich condition, the readings will get worse; if the engine is running too lean, the readings will get better.
based on my personal experience, an engine of mine which failed, and I assumed to be running too rich, was in fact proved by the above test to be running too lean.
Sounds like y0ur fuel pressures might be a little low, and if it was running lean at idle (as the smog tech said), I would suspect that it was also lean under load. Try the above test; it will help you with a definitive diagnosis.
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
interesting...I havent seen a 2500 RPM test done "static" in years, typically the car is first Weighed and then spun up on the rollers for this test. This more closely simulates real driving conditions.
It would seem that if the engine was under a load the Cat's would run a-little hotter, and further reduce the Carbon Monoxides (CO).
Bottom line is...the O2 to fuel ratio is off a bit, or the Cats aren't doing their job.
The ECM will adjust the injector dwell time based on data input from what ever sensors the ECM Utilizes: i.e. MAP, MAFF, TPS, O2 etc. so if one of these sensors is biased this could effect the fuel/air ratio.
http://auto.howstuffworks.com/catalytic-converter2.htm
It would seem that if the engine was under a load the Cat's would run a-little hotter, and further reduce the Carbon Monoxides (CO).
Bottom line is...the O2 to fuel ratio is off a bit, or the Cats aren't doing their job.
The ECM will adjust the injector dwell time based on data input from what ever sensors the ECM Utilizes: i.e. MAP, MAFF, TPS, O2 etc. so if one of these sensors is biased this could effect the fuel/air ratio.
http://auto.howstuffworks.com/catalytic-converter2.htm
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
Inhanced. (dyno)
Basic. (two speed idle.)
Change of ownership only (not sure, maybe two speed idle)
Kern county is in the, Two speed idle catagory. This test is probable less Stringent a test, because it does not require NOX testing. OP has the easier of the two tests....notice how several counties are sub-divided.
http://www.sdvsa.org/CaliforniaSmogZones.htm
Race Director
Joined: Dec 2003
Posts: 14,106
Likes: 930
From: Fremont Ca
2022 C4 of the Year Finalist - Modified
Good luck.My 18,000 original mile 1991 ZR-1,BONE STOCK failed twice before I had to take the car to a smog referee.The state lowered the MAX levels allowable 2 years ago and dont be surprised if they lower them again in the next 2 years.This smog bull$hit is only going to get worse or at least until the state gets all of the older cars off the road.
Team Owner
Joined: Sep 2003
Posts: 20,170
Likes: 672
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Good luck.My 18,000 original mile 1991 ZR-1,BONE STOCK failed twice before I had to take the car to a smog referee.The state lowered the MAX levels allowable 2 years ago and dont be surprised if they lower them again in the next 2 years.This smog bull$hit is only going to get worse or at least until the state gets all of the older cars off the road.
This goofy state is top heavy with morons in charge. Who take money from enviros, that want to return the world back three hundred years.
An option: run some denatured alcohol with the fuel. Helps to reduce hydrocarbon emissions. Not by much, but maybe enough to pass.