Might be moving to DC how do I pass emissions?

ballmode

Lifer
Aug 17, 2005
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Got a WRX with STI turbo/intercooler, ECU tune, and 3" greddy exhaust with STI muffler.

How can I pass emissions?

UPDATE: Found a stock STI exhaust for 150 bucks, cat and all! :)
 
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jlee

Lifer
Sep 12, 2001
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Still have cats? What does DC require for emissions? My Forester passed AZ - all they did was check for codes.
 

DaTT

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Still have cats? What does DC require for emissions? My Forester passed AZ - all they did was check for codes.

Can they detect if certain "functions" are turned off? I have heard mixed replies on this. I have one of my O2 sensors shut off because it was throwing codes after my CAT's due to the race cats no heating up quickly enough.....I am due for emissions scan next month.
 

bruceb

Diamond Member
Aug 20, 2004
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DC DMV is not too specific about which test they will use. But I think if the car has OBD II and does not show any excess smoke (or blue smoke) from the exhaust, they just check for codes. The other two types of tests are probably used for cars that do not have the OBD II or newer systems.

http://dmv.dc.gov/serv/inspection/inspection_main.shtm

Vehicle Inspections - Clean Air
entrance.jpg

The District of Columbia provides vehicle inspection services to ensure residents that vehicles producing high levels of pollutants are not registered and operated in the District. A report is produced to assist your mechanic in diagnosing and repairing any emission related problems that are discovered.
Vehicles are tested using either the IM/240 computer, the Idle test or the On-board diagnostic computer. These test measure the emission levels.
Inspection Information
Find out what information you need to bring for your inspection.
 

shabby

Diamond Member
Oct 9, 1999
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Got a WRX with STI turbo/intercooler, ECU tune, and 3" greddy exhaust with STI muffler.
How can I pass emissions?
As long as you have a cat you should be fine, also most of these places don't test awd cars on the rollers, they just do an idle test and different rpms.

Can they detect if certain "functions" are turned off? I have heard mixed replies on this. I have one of my O2 sensors shut off because it was throwing codes after my CAT's due to the race cats no heating up quickly enough.....I am due for emissions scan next month.

Cat/evap/egr/o2/ac readiness codes are stored in the ecm, if your o2 is turned off your readiness code will throw a flag when they scan it, instant fail.
 
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DaTT

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Cat/evap/egr/o2/ac readiness codes are stored in the ecm, if your o2 is turned off your readiness code will throw a flag when they scan it, instant fail.

Which brings me to my next question then, I have a tune at the ready with the o2 sensor on, but a code will not flag for a week, sometimes 2 weeks. Will it flag it then too if I test it before the light comes on? Or is there a certain amount of on/off's that are required before the check is complete?
 

jlee

Lifer
Sep 12, 2001
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Cat/evap/egr/o2/ac readiness codes are stored in the ecm, if your o2 is turned off your readiness code will throw a flag when they scan it, instant fail.

Not with a proper tune, it won't. ;)
From the 2004 Forester XT VF39/STi IC w/launch control map notes from Cobb:
CEL Codes Defeated [WHEN USING AS BASE MAP] (** means new to latest revision):
P0037 - Rear O2 Sensor Heater Control Circuit Low **
P0038 - Rear O2 Sensor Heater control Circuit High **
P0137 - Rear O2 Sensor Circuit Low Voltage
P0138 - Rear O2 Sensor Circuit High Voltage
P0139 - Rear O2 Sensor Circuit Slow Response
P0420 - Catalyst System Efficiency Below Threshold
P0545 - Exhaust Gas Temperature Sensor Circuit Low **
P0546 - Exhaust Gas Temperature Sensor Circuit High **
P1301 - Misfire Detected (High Temperature Exhaust Gas) **
P2096 – Post Catalyst Fuel Trim System Too Lean Bank 1
P2097 - Post Catalyst Fuel Trim System Too Rich Bank 1
 

shabby

Diamond Member
Oct 9, 1999
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I have a tune at the ready with the o2 sensor on, but a code will not flag for a week, sometimes 2 weeks. Will it flag it then too if I test it before the light comes on? Or is there a certain amount of on/off's that are required before the check is complete?
The o2 readiness code will simply say its not ready, the guy doing the test will just tell you to come back in a week or two until it is ready.

Not with a proper tune, it won't. ;)
From the 2004 Forester XT VF39/STi IC w/launch control map notes from Cobb:
Cel's and readiness codes are two totally different things, anyone can disable check engine lights, but i don't believe Cobb let alone any other tuner actually disables or has the ability to disable readiness codes.
 

ballmode

Lifer
Aug 17, 2005
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Well I will need to get a new exhaust for sure as I pollute with no cat

I'll have to possibly retune the car too... hmm
 

Viper GTS

Lifer
Oct 13, 1999
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For what it's worth my Viper passed Oregon DEQ with the downstream O2 sensors ziptied outside the exhaust. Some dumbass put the catback exhaust on it and never bothered to install the sensors.

It was an OBD only test, and it didn't throw a code until a few hundred miles later.

Viper GTS
 

exdeath

Lifer
Jan 29, 2004
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OBD tests for more than just MIL codes.

You are normally allowed for a number of systems/monitors reporting not ready or not present, usually no more than 2-3, and still considered passing. Catalyst efficiency monitor is one of them (downstream O2s) that are "optional".

Also be aware that if you flash a tune or perform any kind of reset of the ECU that you automatically won't be able to pass for several hundred miles as the ECU will report "not ready" until the onboard drive cycle is completed.
 
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DaTT

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Feb 13, 2003
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OBD tests for more than just MIL codes.

You are normally allowed for a number of systems/monitors reporting not ready or not present, usually no more than 2-3, and still considered passing. Catalyst efficiency monitor is one of them (downstream O2s) that are "optional".

Also be aware that if you flash a tune or perform any kind of reset of the ECU that you automatically won't be able to pass for several hundred miles as the ECU will report "not ready" until the onboard drive cycle is completed.

So if I put the tune back on a week or so before my test and turn off the o2 code (it is after the cats), I should be fine is what you are saying? I know it passes the idle and driving test with flying colours.
 

shabby

Diamond Member
Oct 9, 1999
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So if I put the tune back on a week or so before my test and turn off the o2 code (it is after the cats), I should be fine is what you are saying? I know it passes the idle and driving test with flying colours.

That depends if you can complete your oem's drive cycle before the emission test.
 

jlee

Lifer
Sep 12, 2001
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Cel's and readiness codes are two totally different things, anyone can disable check engine lights, but i don't believe Cobb let alone any other tuner actually disables or has the ability to disable readiness codes.

Ahh ok, for some reason I was thinking CEL only.

From NASIOC:
Cobb Tuning said:
The AccessPORT does not manipulate any of the emission readiness functions of the ECU. If you have an AccessPORT version 2, free AccessTUNER Race software would allow you to disable trouble codes (for off-road use only).

Bill
I wonder what exactly is looked for by the OBD test, and what exactly is changed in the tune, then. Mine passed fine, but I do still have a cat.
 

ballmode

Lifer
Aug 17, 2005
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After looking at my situation, I basically would have to get a whole new exhaust as I sold my stock one. I'd have to get my car retuned as well.

I'm looking at probably $1000 ish or more. I'd hate to spend any money into this car that wasn't either for a repair or to make the car better. I'm thinking about selling it.

What are my alternatives to getting a good exhaust system with a cat? I'm thinking my only option is oem STI exhaust.
 

jlee

Lifer
Sep 12, 2001
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After looking at my situation, I basically would have to get a whole new exhaust as I sold my stock one. I'd have to get my car retuned as well.

I'm looking at probably $1000 ish or more. I'd hate to spend any money into this car that wasn't either for a repair or to make the car better. I'm thinking about selling it.

What are my alternatives to getting a good exhaust system with a cat? I'm thinking my only option is oem STI exhaust.

A catted downpipe alone won't be enough?
 

DaTT

Garage Moderator
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Feb 13, 2003
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Have you tried any STi forums for anyone selling their stock exhaust?
 

DaTT

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Maybe RGun will chime into this thread, he has an STi that is heavily modded and may be able to offer some assistance as well.
 

manimal

Lifer
Mar 30, 2007
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A buddy of mine recently put a aftermarket exhaust on his2004 STI. I emailed him to see if he still has stock.


He lives in chicago so its not too far from us now. Sorry to hear your leaving indy. Lets grab lunch before you go bro!
 

NutBucket

Lifer
Aug 30, 2000
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I'm pretty sure the only thing the OBD test looks for is CELs and the Readiness Monitors. What I'm not sure about is whether disabling a CEL code prevents the readiness monitor from being set.

But, I have read that more than one person has passed CA emissions with an OTS Cobb Stage2 tune. This would suggest the readiness monitor will set even with disabled CELs. The only way to really know would be to get a OBDII scanner that reads readiness monitors. Unfortunately, not all of them do.
 

shabby

Diamond Member
Oct 9, 1999
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I'm pretty sure the only thing the OBD test looks for is CELs and the Readiness Monitors. What I'm not sure about is whether disabling a CEL code prevents the readiness monitor from being set.

The only thing disabling a cel does is it disable the light from showing up on your dashboard, nothing more nothing less. If people in ca passed with the cobb tune its because they had a cat.
 

NutBucket

Lifer
Aug 30, 2000
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Obviously you need a cat to pass the sniffer. I was only referring to what they check for when they plug into the ODB port.