The Central Hub for DSM Community and Information

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. This is where the DSM platform history is documented and archived. Log in to help us in our mission, and to remove most ads from the browsing experience.

Tips for passing smog in California. I'm a smog tech.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

rajasai420

Probationary Member
15
7
Aug 23, 2007
Millbrae(Bay Area), California
The smog check consists of 3 parts visual, functional, and tailpipe emissions. Fail any part and you won't pass the test.

Functional: tests performed are timing check(eclipse excluded timing N/A), gas cap pressure test, check engine light, ECU, and EGR (awd only).

OBD1
IF pre 96(OBD1) all you have to worry about is if your check engine light is on. If on, unplug your battery for a few minutes and plug back in right before smog, light should go off and as long as it doesn't turn back on during the test your all good.

OBD2
96 and up(OBD2)cars are more troublesome you cant just unplug your battery. You also can't just erase check engine codes and lights. Smog checks requires the smog machine to communicate with the ECU thru OBD2 port. Most cars will pass this functional test as long as you still have your stock ECU and you don't have any check engine codes(no CAT?) and if you haven't reset the ECU by unplugging the battery(you need to have you emissions components to be monitored explained later).
Also for awd cars they test the EGR so you need to have that as well. If front wheel drive they don't test it but they check to see if it is there and the ECU monitors it . Other cars get tested for timing but since ours isn't adjustable we get to slide on that.

Visual inspection for emission components consist of checking for PCV, EGR, fuel leaks, CAT, O2 sensors, air pump(eclipse don't have), EVAP(charcoal canister), TAC hose(eclipse don't have), disconnected, failed or modified vacuum hoses and sensors.

Ignition systems are ok to modify as long the centrifugal or vacuum advance mechanisms aren't tampered with(ours are computer controlled so no worries there) but no ignition piggy back controllers. After market intake manifolds are ok as long as all the original provisions for the oem emission controls are there. EX: EGR, air pump, vacuum lines,PCV etc... Intercoolers are acceptable but only for oem turbochargers.

As for your visuals related to modified parts, any part that affects emissions in any way is a fail without a CARB sticker. You basically fail for most mods. EX: injectors, cams, nos, fuel pump, FPR, AFC, after market Turbo, FMIC for after market turbo, intercooler piping, BOV that doesn't recirculate, downpipe(especially with no cat), exhaust piping, headers, Boost controller, any piggyback controller, throttle body, etc.....

Acceptable parts are Ignition, intake manifold, exhaust muffler, intake cone, radiator, tranny, differential, body kits, spoilers, speakers, battery, etc....

Don't worry too much about it all tho because the technician isn't gonna worry about most of that stuff because he wont even know that it is there. Don't ask don't tell, if asked LIE. As long as it's not noticeable the tech probably wont notice either.

The thing to worry about the most is your intercooler piping, header, and intake piping and anything else that is obvious when you crack your hood. Cone filters are OK but intake piping and changing the MAF in any way is not. PCVs are a part of the visual and so are any loose vacuum lines so they need to be connected.

Turbos: Cant be modified, but if you have an internal wastegate you are OK with your turbo long as your turbo looks stock and you have your stock manifold. If you have your heatshield to block the view of the turbo as much as you can. If you have an external gate hide it. If you have a polished turbo your outta luck, unless the smog tech just doesn't notice.

Upper and lower intercooler piping needs to be hidden because those are illegal and lead the tech to find your FMIC(if so equipped) which is also illegal on a after market turbo. If you could hide your piping or put back the stock pipes the technician wouldn't even trip off of your front mount. Recirculating your after market BOV is legal, if you are venting which isn't allowed then recirculate it or put back your stock BOV.

THE MOST IMPORTANT THING TO REMEMBER ABOUT VISUAL IS THAT IT IS %100 PERCENT UP TO THE TECHNICIAN WHETHER OR NOT TO PASS YOU FOR VISUAL. Don't tell him anything about your fuel pump, AFC, injectors or anything at all. Try to keep all your parts looking stock, paint things black, and nothing shiny.

Emissions:
Without a CAT your car won't pass visual and it sure as hell won't pass emissions. You also have to have a cat so you won't have a check engine code. Also a new cat will always work better than a used one.

You need to have all your emissions components being monitored by the ECU. Which means if you unplugged your battery for a while or if you reset your trouble codes recently your ECU will be erased. You then must drive you car around and put the car thur its drive cycle to have your ECU monitored. This is very hard to do. You will need to drive at a slow and steady pace at 30 up to 65 mph without stepping on the brake. You will need to do this for at least one whole tank of gas or more. Just drive really steady whenever you drive and make sure you hop on the freeway too.

As for you emissions you can fail for high HC(fuel), CO(carbon monoxide), and NOx(Oxide of nitrogen). These are the only three you can fail for. If your CO or HC is high you could lean out a bit with your afc. If your NOx is high you should richen it up with an afc or other contorller. You can do this after your test, most test onlys allow a free retest if you fail. So adjust your AFC then go back. Also hide the AFC and sssshhhh.

HC and CO are usually high due to unburned fuel so you lean it out. NOx is high when it get's too hot in the combustion chamber usually from being lean. Richen it up and Nox will go down for sure. Fuel will also help cool it down.

DON'T RICHEN TOO MUCH OR YOU WILL MAKE HC AND CO FAIL AND LEANING IT OUT TOO MUCH WILL MAKE NOx GO UP. FIND A GOOD BALANCE.

Advancing your timing will increase NOx but will reduce HC AND CO and retarding your timing will reduce NOx and bring up your HC and CO. FIND A GOOD BALANCE.

These are just tips for a failed emissions sometime it still won't be enough and further diagnosis is gonna be required.

Make sure your car is good and warmed up, Plugs are good, O2 sensors are good, no vacuum leaks, clean air filter, clean fuel filter, clean injectors,stock boost is best, also the best time to go is when it is really busy, the technician is more likely to skip something and just trying to speed though the tests,and that's pretty much it. GOOD LUCK
 
Over in Texas you don't run the car on a dyno either like we do down in California. In Texas you probably still only do a 2 speed idle. Over in California we run it at 15 then 25 miles an hour on a dyno to get the readings(AWD exempt). We also plug up cars that are 96 and up to our machine though the obd2 port to pull codes and check your moniters. In Texas you probably don't test obd2 at all. We have the most ####ed up smogs in the country over here California.
 
Actually the test station here in Houston does OBD2 on our 2000 KIA Sportage (Houston and Dallas have stricter tests). But yes, we only have the 2 speed idle. However, for some strange reason the last 3 years (since I upgraded the turbo and went DSMLink) they only do an OBD1 test on the Eclipse....strange (but not complaining).
 
A lot of the CA crowd already knew this, just from the people who fail and complain about it to everyone else. In any case, thanks for posting it rasajai, it's good to get the knowledge confirmed. :)

One thing that seems to be a gray area, I've heard people arguing both sides, and am pretty sure at this point it's up to the smog tech... what about aftermarket intercooler pipes for a factory-turbo car? FMICs on a factory-turbo car?

Also, I've heard that aftermarket BOVs, FPRs and WGs are acceptable, but only so long as they are non-adjustable (how a lot of the Ford guys apparently get by with upgrades, as there are factory high-perf parts available). Any truth to this one, or is non-adjustable just more likely to be missed in the visual?
 
rajasai420, Are you a smog tech???
You seem to know a lot about smogging cars in CA.

So, I have a 97 GSX (mods in profile) with DSMLink and a 95 ECU.
What, if any, (Fingers Crossed) are some problems I may have while getting F##ked... I mean smog tested here in glorious California?

Yes.

95 ecu will be ok as long as you arent shutting off you monitors with your dsmlink. Go to there website they talk a little bit about turning off your check engine light by disabling your monitors. They are both illegal but don't ask don't tell.

By looking at your engine bay the there are three things that are gonna send red flags. Your intake, it looks legal to me but not all techs will think this way. Do you have a carb sticker for it? If not then you could try to argue with the tech about how the MAF isn't changed or go greddy to see if you can get a carb number. Your piping and fmic is ok because your turbo looks stock. As long as the tech believes the turbo is stock your ok. Your bov is ok as long as you recirculate it. Remember you can argue these with the tech if he questions you. If he doesn't believe you tell him to check under appendix K of the smog check inspection manual.

Your dsmlink worries me because of the monitors possibly being disabled. Also with those larger injectors I would recommen a lean tune. Remember that they only test at 2500RPM and idle.

A lot of the CA crowd already knew this, just from the people who fail and complain about it to everyone else. In any case, thanks for posting it rasajai, it's good to get the knowledge confirmed. :)

One thing that seems to be a gray area, I've heard people arguing both sides, and am pretty sure at this point it's up to the smog tech... what about aftermarket intercooler pipes for a factory-turbo car? FMICs on a factory-turbo car?

Also, I've heard that aftermarket BOVs, FPRs and WGs are acceptable, but only so long as they are non-adjustable (how a lot of the Ford guys apparently get by with upgrades, as there are factory high-perf parts available). Any truth to this one, or is non-adjustable just more likely to be missed in the visual?

IC pipes and fmic are ok only on a OEM turbo.

Only OEM wastegates and FPR are allowed unless you got a carb sticker. BOV are OK as long as you recirculate. The items will only be missed during visual if they look oem. A tech will never find any adjustable or not adjustable FPR, BOV, or WG as long as they look OEM. Looking OEM is the key. Or carb sticker. Factory installed parts like from TRD or SVT are all legal.

What's the best way for a fwd 1g to pass if it's been modified? They can put the fwd on the dyno, if your afc settings are "good" then even on the 15 and 25 mph test it should pass right?

Good chance it will pass. But a lot of variables EX: Is EGR working to control NOx. Is pcv stuck open or close to control HC and CO. Running hot? Is CAT functioning? Sensors all in order? If all this is good then you will most likely pass the emissions. Visual and functional testing is gonna be totally different from emissions testing.
 
Yes.

95 ecu will be ok as long as you arent shutting off you monitors with your dsmlink. Go to there website they talk a little bit about turning off your check engine light by disabling your monitors. They are both illegal but don't ask don't tell.

By looking at your engine bay the there are three things that are gonna send red flags. Your intake, it looks legal to me but not all techs will think this way. Do you have a carb sticker for it? If not then you could try to argue with the tech about how the MAF isn't changed or go greddy to see if you can get a carb number. Your piping and fmic is ok because your turbo looks stock. As long as the tech believes the turbo is stock your ok. Your bov is ok as long as you recirculate it. Remember you can argue these with the tech if he questions you. If he doesn't believe you tell him to check under appendix K of the smog check inspection manual.

Your dsmlink worries me because of the monitors possibly being disabled. Also with those larger injectors I would recommen a lean tune. Remember that they only test at 2500RPM and idle.

Thanks for the input.
The GReddy Turbo Upgrade and Intercooler Kit is CARB Legal.
http://arb.ca.gov/msprog/aftermkt/devices/eo/D-397-3.pdf
http://arb.ca.gov/msprog/aftermkt/devices/eo/D-397-2.pdf

The intake is part of the kit, so it is covered under the EOD-397-3.
I have the small 18r intercooler from GReddy, so that too is covered under the EOD-397-2.

All of my monitors are enabled and ready.
I have no CEL's what so ever, and haven't had any for this car at all.

I've been to a local smog shop, and the guy is very cool, so hopefully he'll be cool and over look the AFPR.
My fuel trims are +/- 2% of 0, and base pressure is set to 43psi.
I have a new OBDII and CARB certified high flow cat from Magna Flow that is spec'd for a full size Chevy pick-up, and I've passed with the same model on my late GST.

Thanks for all of your info, looking forward to getting smogged in the next couple of months so I can throw some 272's in and really take advantage of that 18g compressor wheel.
 
rajasai420,

Great write-up.

I've been trying to locate a copy of the Smog Check Inspection Manual. Specifically Appendix K as it applies to intercoolers with stock turbos. Do you know where I can locate one?
 
rajasai420,

Great write-up.

I've been trying to locate a copy of the Smog Check Inspection Manual. Specifically Appendix K as it applies to intercoolers with stock turbos. Do you know where I can locate one?

Yeah, I posted that in the NorCal section, I'll put up a link.
http://www.dsmtuners.com/forums/norcal-dsm-forum/254459-carb-numbers-2.html there we go.

Anyway possible way to get this stickied?

"THE MOST IMPORTANT THING TO REMEMBER ABOUT VISUAL IS THAT IT IS %100 PERCENT UP TO THE TECHNICIAN WHETHER OR NOT TO PASS YOU FOR VISUAL."

Very true!

I think its already a tech article.
 
can you tune the car with DSM link to run lean at 15 and 25 MPH?
so when tested it would show good results. save that file for smog
testing only. is it possible to detect DSM link when being smog tested.
 
I was under the impression any aftermarket factory replacement hardware was ok as long as it had a California Air Resource Board Number stamped on it.
 
I was failing smog with my 95 gsx which was pretty much stock except a filter. It was my front o2 sensor failing. I was getting a P0170 CEL, but it doesnt directly say its the o2 sensor, but for various possibilities. The o2 sensor being one of them. After putting DSMLink and showing the o2 sensor was not cycling properly, this explained why I failed being a gross polluter with a lot of unburned gas. Replaced the front o2 and passed like I knew it should. Using some old NGK 7s and magnecore wires that have been passed down from 3 dsms. Stock turboback with original cat that, and is 140k miles. I'm sure replacing those things would have made my #s better, but I still passed with flying colors. So if you are not passing, there is one main culprit to blame, and the little stuff, might help if you are barely failing, but in my case, even keeping old crap still made me pass if you solve the true problem.
 
The smog check consists of 3 parts visual, functional, and tailpipe emissions. Fail any part and you won't pass the test.

Functional: tests performed are timing check(eclipse excluded timing N/A), gas cap pressure test, check engine light, ECU, and EGR (awd only).

OBD1
IF pre 96(OBD1) all you have to worry about is if your check engine light is on. If on, unplug your battery for a few minutes and plug back in right before smog, light should go off and as long as it doesn't turn back on during the test your all good.

OBD2
96 and up(OBD2)cars are more troublesome you cant just unplug your battery. You also can't just erase check engine codes and lights. Smog checks requires the smog machine to communicate with the ECU thru OBD2 port. Most cars will pass this functional test as long as you still have your stock ECU and you don't have any check engine codes(no CAT?) and if you haven't reset the ECU by unplugging the battery(you need to have you emissions components to be monitored explained later).
Also for awd cars they test the EGR so you need to have that as well. If front wheel drive they don't test it but they check to see if it is there and the ECU monitors it . Other cars get tested for timing but since ours isn't adjustable we get to slide on that.

Visual inspection for emission components consist of checking for PCV, EGR, fuel leaks, CAT, O2 sensors, air pump(eclipse don't have), EVAP(charcoal canister), TAC hose(eclipse don't have), disconnected, failed or modified vacuum hoses and sensors.

Ignition systems are ok to modify as long the centrifugal or vacuum advance mechanisms aren't tampered with(ours are computer controlled so no worries there) but no ignition piggy back controllers. After market intake manifolds are ok as long as all the original provisions for the oem emission controls are there. EX: EGR, air pump, vacuum lines,PCV etc... Intercoolers are acceptable but only for oem turbochargers.

As for your visuals related to modified parts, any part that affects emissions in any way is a fail without a CARB sticker. You basically fail for most mods. EX: injectors, cams, nos, fuel pump, FPR, AFC, after market Turbo, FMIC for after market turbo, intercooler piping, BOV that doesn't recirculate, downpipe(especially with no cat), exhaust piping, headers, Boost controller, any piggyback controller, throttle body, etc.....

Acceptable parts are Ignition, intake manifold, exhaust muffler, intake cone, radiator, tranny, differential, body kits, spoilers, speakers, battery, etc....

Don't worry too much about it all tho because the technician isn't gonna worry about most of that stuff because he wont even know that it is there. Don't ask don't tell, if asked LIE. As long as it's not noticeable the tech probably wont notice either.

The thing to worry about the most is your intercooler piping, header, and intake piping and anything else that is obvious when you crack your hood. Cone filters are OK but intake piping and changing the MAF in any way is not. PCVs are a part of the visual and so are any loose vacuum lines so they need to be connected.

Turbos: Cant be modified, but if you have an internal wastegate you are OK with your turbo long as your turbo looks stock and you have your stock manifold. If you have your heatshield to block the view of the turbo as much as you can. If you have an external gate hide it. If you have a polished turbo your outta luck, unless the smog tech just doesn't notice.

Upper and lower intercooler piping needs to be hidden because those are illegal and lead the tech to find your FMIC(if so equipped) which is also illegal on a after market turbo. If you could hide your piping or put back the stock pipes the technician wouldn't even trip off of your front mount. Recirculating your after market BOV is legal, if you are venting which isn't allowed then recirculate it or put back your stock BOV.

THE MOST IMPORTANT THING TO REMEMBER ABOUT VISUAL IS THAT IT IS %100 PERCENT UP TO THE TECHNICIAN WHETHER OR NOT TO PASS YOU FOR VISUAL. Don't tell him anything about your fuel pump, AFC, injectors or anything at all. Try to keep all your parts looking stock, paint things black, and nothing shiny.

Emissions: Without a CAT your car won't pass visual and it sure as hell won't pass emissions. You also have to have a cat so you won't have a check engine code. Also a new cat will always work better than a used one.

You need to have all your emissions components being monitored by the ECU. Which means if you unplugged your battery for a while or if you reset your trouble codes recently your ECU will be erased. You then must drive you car around and put the car thur its drive cycle to have your ECU monitored. This is very hard to do. You will need to drive at a slow and steady pace at 30 up to 65 mph without stepping on the brake. You will need to do this for at least one whole tank of gas or more. Just drive really steady whenever you drive and make sure you hop on the freeway too.

As for you emissions you can fail for high HC(fuel), CO(carbon monoxide), and NOx(Oxide of nitrogen). These are the only three you can fail for. If your CO or HC is high you could lean out a bit with your afc. If your NOx is high you should richen it up with an afc or other contorller. You can do this after your test, most test onlys allow a free retest if you fail. So adjust your AFC then go back. Also hide the AFC and sssshhhh.

HC and CO are usually high due to unburned fuel so you lean it out. NOx is high when it get's too hot in the combustion chamber usually from being lean. Richen it up and Nox will go down for sure. Fuel will also help cool it down.

DON'T RICHEN TOO MUCH OR YOU WILL MAKE HC AND CO FAIL AND LEANING IT OUT TOO MUCH WILL MAKE NOx GO UP. FIND A GOOD BALANCE.

Advancing your timing will increase NOx but will reduce HC AND CO and retarding your timing will reduce NOx and bring up your HC and CO. FIND A GOOD BALANCE.

These are just tips for a failed emissions sometime it still won't be enough and further diagnosis is gonna be required.

Make sure your car is good and warmed up, Plugs are good, O2 sensors are good, no vacuum leaks, clean air filter, clean fuel filter, clean injectors,stock boost is best, also the best time to go is when it is really busy, the technician is more likely to skip something and just trying to speed though the tests,and that's pretty much it. GOOD LUCK
I wish you were here in Chico I need help bad
 
I wish you were here in Chico I need help bad
Talk about reviving an ancient thread.... biggest thing I learned to help pass smog while living in California was to move out of California. No issues now. Oh and when I did live there I paid a community member to push my smog through. Heard now they want pics of the engine bay though.
 
This post revival reminded me of my original reason for joining.

I would like to replace my RX8 rotary engine with a 4 cyclinder Ecotec one. I know that this is technically allowed under CA rules, but the devil is in the details.

I would like to find a smog tech / referee who could spend some time walking me through what I can and cannot do. I know this could take some time, and I don’t expect someone to help me through the process for free.

If anyone here can help, either directly or by referral, I’d greatly appreciate it. Please feel free to DM me.

Thanks in advance!
 
Talk about reviving an ancient thread.... biggest thing I learned to help pass smog while living in California was to move out of California. No issues now. Oh and when I did live there I paid a community member to push my smog through. Heard now they want pics of the engine bay though.
I have the stock manifold but both cans are empty and third is intact I used my autel scanner and it didn't throw a code and I was getting exhaust numbers but I don't know what the baseline numbers should be.
 
Add Value - Be Respectful - No Trolling - No Misinformation - Participate Often!
Support Vendors who Support the DSM Community

Build Thread Updates

Latest Classifieds

Back
Top