trax

Background about the LT1 OBDII PCM
The PCM makes use of two techniques to monitor your vehicle's emissions systems:
--DTC's (Diagnostic Trouble Codes)
--Readiness monitors

A quick glance in the Helm's manual (Page 6E-914, book 2) shows that the the LT1 PCM has 6 readiness monitors:
--Catalyst
--EVAP system
--HO2S
--HO2S Heater
--EGR
--AIR

Using LT1 edit, you can program out some DTC's like AIR. You can also do some basic tricks, like telling EGR only to open at 6700 or 6800 RPM, which basically ensures that the PCM will never try to use it.

However... you cannot program out the readiness monitors. This fact has been confirmed by Madwolf as well as the guys at Speed Inc... That's why you might be able to remove your EGR and AIR hardware, but a scan tool will show that those readiness monitors are not ready. Unlike the LS1 cars, there is simply no known way to hack them out of the PCM.


Illinois Emissions Testing
In Illinois, vehicles made between 1996 and 2000 are allowed to fail 2 readiness monitor checks. This allows you to take your pick of the ones above. Which brings us to the combination I chose...


A bit about my car
--Heads / cam
--No cats
--Hooker LT's w/ O2 bungs
--Mufflex Y w/ O2 bungs
--Rear O2 simms
--EGR simulator
--AIR pump
--EVAP
--Full dyno tune at Speed Inc.

It took some creativity, but I was able to adapt the stock AIR check valves to mount to the bungs on the Hooker's. Then I connected the front O2's to the bungs on the Mufflex, and got creative running some rubber hose to the AIR pump in the engine compartment. I'll have pics of this up shortly.


AutoZone Scan tool results with this setup
EVAO - not supported
O2S - ready
HO2S - ready
EGR - ready
Sec. AIR - not ready
Catalyst - not ready

It took three days of driving and roughly 100 miles for the monitors to show up. I took these readings five minutes before I rolled my car into the EPA facility. The car passed with flying colors.

Hope this helps some of you guys out.

stereomandan

Great info! Thanks for sharing. I'm surprised that it took 3 days and 100 miles of driving for the monitors to show up.

Dan

blind527

God I miss Illinois! Virginia sucks so bad.......I wish I could fail 2 monitor tests!

TCAL95Z

Does Illinois just do the plug in test or the roller too?

I used to live in Macomb, Il. In AZ anything OBDII just gets the plug in test and EVERYONE PASSES!
Which makes having a OBDI suck!

superkia8

Old post but hopefully someone can chime in here? Does anyone know how to get the tests to go to ready? I used my buddies hptuner to scan my car and my EVAP reads " N/A ", not really sure why and my catalyst reads " incomplete " which Im assuming means not ready due to the test not being completed? Anyone know what it is that makes these tests complete? Someone has to have some nowledge in this area, I hope!

H02S = COMPLETE
H02S HEATER = COMPLETE
SECONDARY AIR = COMPLETE
EVAP = N/A
CATALYST = INCOMPLETE
EGR = INCOMPLETE

The EGR has been edited out so I understand that and Im hoping if I change the parameters on its operation it will go to complete? Dunno!


If anyone could help it would be appreciated.

Thanks,
Rich

2cub49

If you need to have the one more monitor ready you could check out this thread for some information that may be helpful.

http://web.camaross.com/forums/showthread.php?t=366280

2cub49

Our cars don't have the EVAP monitor so that's why it's unsupported.
We only have to pass 3 out of 5 monitors ready here in ny.

jchevy

.


I hope to god thats true. When emissions comes around, im going limp my car to the place with my obdii computer in and a stock tune. My headers have emissions hook ups and all the smog equipment is still on my car. I should be good, but i am really worried about that visual and having moved cats. I need to rig up a ghetto y-pipe with some cats before i go.

romoranger

when i went to my emissions test in az they didn't do a visual test. they were like "nice car whats done to it" i told them it was cammed and i think they were in awe. then it passed and i was like holy crap how

jchevy

Last year when I went I had a much smaller cam and SLP shorty headers which retain the factory locations of the cats. They did the visual and as soon as they saw the headers i had like 4 guys going over the car with a fine tooth comb. And they werent checking it out or anything like it was cool, they never even said anything to me.

2cub49

My car passed with a Madwolf tune.
They only care about the monitors if all they're doing is an OBDII scan.
The tune won't make a difference as the test doesn't run anything to determine if it's stock or not.

truedualws6

Old post, but you would never pass in CA without cats.

MachinistOne

Anybody have more info on the ca smog situation, how extreame can we go? I am doing a new motor here soon and need to look into this more...

TCAL95Z

I know of many LS1 cars with OBDII passing with big cams, no cats ect as long as their tune shows no codes or problems when they hook up to your computer.
From what I have heard it's that way for all OBDII beacuse there isn't a roller test.

as far as I know the biggest Lt1 cam to pass in Phoenix is a cc306 in a LT1 with OBDI

jchevy

Im just worried about failing the visual, I know for sure I can pass their computer test.