So I can't seem to get my truck to pass emissions due to the fact the catalyst and evap systems come up as not ready.

My truck is a 2004 that originally came with a 4.8L but now has a 6.0L. I also have aftermarket cats which I put on over a year ago. I haven't had any DTC's since I changend the cats so I don't think they are causing any problems.

I have completed the GM drive cycle many times as per the recommendation but I still won't pass.

Any suggestions would be greatly appreciated.

 

I believe you are allowed to have one rediness check "not ready" and still pass. I would just properly delete all of the catalyst efficiency codes and rear 02 codes and be done with it.

Tip for the Evap rediness that helped me--fill up to the brim with fuel and do as many short trips to operating temp as you can with a full cool down inbetween. If there are no pending codes, you just didn't hit the correct amount of hits or cycles.

 

do you have the tune??? or a log??

 

I am using CMR for the tuning so if you can read that I will send you a copy of the current tune.

 

I tried to turn off everything that had to do with the rear O2 sensors and they just came up as not ready. Which codes should I change to do what you are suggesting? It sounds like I went a little to far by turning everything off. Also what is the difference between putting a 1, 2, or 3 next to the code?

 

I thought you are using HPTuners?????


If you are you can send me your bin file to
calliedusty@sbcglobal.net

The 0,1,2,3 are report selections. 0 is report on first error, 1, is report on 2 error, 2, check but dont report, 3, is dont check.
you want them on 1 if it is all legal...

 

I only use HP for scanning and smoothing VE & timing tables. I then copy into CMR.

 

evap test will only run between 1/4 and 3/4 tank of gas.

 

Good to know. I am currently at a 1/2 tank with no results.

I have also heard that the tests might be done in a certain order. If one test isn't completed it won't complete any tests after. Not sure if that made any sense or not.

 

It's actually pretty tough to get the evap test to run, not only does the tank have to be between 1/4 and 3/4, but the ambient temp has to be between a certain parameter (something like 30 and 87*, can't remember exactly), and you have to drive a certain speed for a certain amount of time...it's amazing that evap monitors ever run lol.