Stupid I/m monitors

[swathdiver]

I don't have the shop manual for your generation but you might want to see what it says for your truck. Disconnecting the battery brings you back to zero. So if it enough driving was almost done to trigger it, such progress has been erased.

 

[kitttransam]

This all started because I had the catalyst efficiency code. I replaced the cats. The code is gone as I erased it after the repair but wonder if something is just causing it to not go to ready. That video hit close to home but they went months trying to get it to set. Funny thing is I checked my 99 Silverado 2500 which I barely drive and all it’s monitors are set. My dads 04 he has to unplug his battery after hauling a trailer because it acts up and he said his monitors come back rather quick. Maybe this pcm is looking for what the old cats was doing.

 

[kitttransam]

Well see what happens. Get my permit and take another drive.

 

[mattt]

My brother has had problems with his I/M readiness tests completing in his 01 Silverado. One thing that somehow comes into play with the I/M tests is having the A/C running. I don't know why, but my brother fought an I/M readiness test for over a year. At that time his A/C was inoperable. As soon as he got his A/C repaired, the last incomplete I/M test completed. Just thought I'd mention this as it isn't something you'd think would come into play, but it did on an 01 Silverado.

 

[kitttransam]

Ok I think I know why I’m having such trouble setting the catalyst monitor. Well as I’ve stated I replaced the cats. Well I bought the whole ypipe assembly. And my only option since I live in good ol California where options for a new catalytic converter is limited because of our ca approved cats. I bought the ca approved maganaflow cat assembly. Well this one was slightly different. It has small precats towards the manifold flanges. The old assembly did not have this. Guess what those little precats are before the front o2 sensors. I think it’s causing some weirdness with the o2 sensors. Yeah other thing also is I have a federal vehicle. But I don’t think these new cats are even a original design in the first place.

 

[kitttransam]

Well I’m just gonna punch out the material in those precats that wasn’t made for this car in the first place. I’ll let you guys know if this fixed the problem.

 

[swathdiver]

Well I’m just gonna punch out the material in those precats that wasn’t made for this car in the first place. I’ll let you guys know if this fixed the problem.

That's what I was thinking. I did the opposite. Mine has California emissions and I put on Federal Cats. The only difference that I could discern are the lack of CARB numbers for my GMT900.

 

[kitttransam]

Guess what I punched those precats out yesterday. Drove it this morning and catalyst is ready on the monitors. Just goes to prove the wrong parts can cause some mayhem.

 

[mattt]

What did you do to "punch out" the cats? Did you remove them and replace with straight pipe or something else? Nice work....congrats!

 

[swathdiver]

What did you do to "punch out" the cats? Did you remove them and replace with straight pipe or something else? Nice work....congrats!

Probably a long extension and a hammer!