I am trying to find out if there is a way to program our OBDII computers to get around the readiness issues for emissions tests. If anyone can help shed some light on this I would appreciate it.

 

I was also wondering about this as well. It seems like there are LS1's out there runing longtubes with out AIR and EGR. And they have passed emissions. But I havent been able to find out how they are doing this, or if it can even be done.

I would like to know. Because if there is a way to make my 97 formy to trick the pcm to go into ready mode for the egr and air, then I know others are going to want to know how to do the same thing.

Mike

 

There's no way to program around the tests. There are ways to pass the OBD2 testing by still passing the readiness tests.

Confused yet?

There are 5 readiness tests in the PCM. They include EGR, AIR, 02 heaters, catalyst, fuel system and cannister purge...I may be off on that last one but there are 5 tests.

First and most obviously you cannot have any active codes stored in the PCM or a lit SES light.

You'll have to have somebody else reconfirm this because I'm not 100% sure what the hear break is, but from 1996 to I think 1999, you must have any 3 of the 5 readiness tests set to "ready" to pass the emissions check. Starting in 2000, it is 4 out of the 5.

So, for example, I have AIR and EGR deleted but that still leaves me 3 of 3 to pass with. As for how the later year cars are doing it, I suppose you could keep the AIR system and just not have it hooked up, so the PCM would see it and think it was there and pass you on your readiness monitor.

The other thing I did was use rear 02 simulators rather than just turning them off in the PCM with LT1 edit. This way the catalyst function and 02 heater tests still run, otherwise they would not.

But there is no way to fool the PCM or reprogram it to say "ready" on all the tests...you have to work around it to get the 3 or 4 "ready" that you need depending on your year.

Here's a tech piece from the EPA that gives the details on the readiness tests.

 

sounds like a stupid question but could you pass emissions with air deleted by just pulling the pcm fuse and then running an obd2 test??

the reason im asking is because i threw away my bleed valve and vacuum solenoid for the air injecion system and now its throwing a code at me because i have the actual air pump connecte and running but those other components arent hooked up. I have to pass emissions tomorrow...

 

I have Casper Electronic 02 simms and I cannot get the readiness to go to ready for 02heat or 02 or catalyst. I checked to see how the computer interfaces with the heaters and I found out there is no direct interface between the 02 heaters and the PCM. On a cold start the PCM sends a bias voltage to the sensors approximately 450mv and as the heater heats the sensor the voltage will typically drop below 300mv but can go the other way. The time allowed depends on initial ECT and air flow. But the way I understand it 300mv-700mv is the threshold. I can't remember now but my simms switch somewhere around 400mv - 6or 700mv which may be why I never get the heater readiness. But I will have to hook up my scanner to double check the simm voltages. Anyone have any other ideas as to why I can't get them to ready?

 

By pulling the fuse or resetting it by removing power, or even clearing the codes with a scan tool will automatically reset the 2nd air sys readiness to not ready. As long as it is unhooked or throwing a code the computer can never complete the test so it will never change to ready. Hope that makes sense. This subject really gets under my skin because I drive my car very little probably less then 1000 miles per year and it will not pass emissions. I have a 72 camaro that polutes a lot worse than my 97 without cats and I can drive it anywhere and be legal. Go figure. I believe there should be some relief for cars that are not daily driven.

 

so your saying that you can actually fail one of the "ready" tests?

So if my egr is deleted from the pcm. And as long as the rest of the sensors are reading ready, then I'll be ok?

Because right now due to my longtubes I beleive the shop deleted the AIR and EGR codes from the pcm. Because I never get a SES. The egr is blocked off, but the shop still has the egr valve it self still sitting on the intake. So I dont know if they did that, just incase I was given a visual? Either way it dont bother me. I just want to pass next year with out problems.

 

yeah...unfortunately that does make sense. I guess I'll have to go buy the missing pieces or get it deleted from the pcm locally so it does say its ready.

 

do the Rear o2 sensors require that the AIR pump first be turned on before they'll report as 'ready' ?

 

One thing I have done in the EGR issue is to remove the valve and block it off, but keep the EGR solenoid hooked up. Then go in with LT1 edit and set the on/off parameters for EGR super high, like the MAP and RPM parameters.

That way the Solenoid...which is the only electric/electronic component in the EGR system, can have the readiness test run on it but the valve isn't physically there and will never run.

Only way I know of to delete the EGR and still pass the EGR readiness monitor.

 

Hey Chris ty for the info. Eventually I will get my webpage up and running. And I would love to pass on any OBD-II tips and tricks for passing emissions. So dont be surprised if I shoot you an e-mail in the future with some more questions

Thanks,
Mike

 

hey Mike, have you ever done the resistor trick for the air pump? Thanks for any info!

 

No I havent.

I'm not due for emissions till next year. But since I have the LT's and no emission stuff on. I want to be ahead of the game, and pass the first time. If im not wrong, you can pay like 20 bucks or somthing and take the test. And its not counted if your or pass. I may just do that now for the hell of it. I need to quit being lazy

 

well...i think i have figured out the resistor trick with the air pump and i already know how to do the egr (keeping the solenoid...just no hooked up). Not to sure because i dont drive the car...I've let it idel for about 45 minutes now. So far so good!

 

can you give me some info on the AIR resistor trick? I may need to do that next year.