i just installed a diablosport programmer on friday and i got a po420. i cleared it and run it for 10 miles and got the code again. i put the tune back to stock and been driving it for around 20 miles and havent gotten the code again. any ideas??? just get a dyno tune and call it a day?? im in california and all we have is 91 octane, any ideas???

 

P0420 is a catalytic converter inefficiency trouble code for bank 1 (drivers side)...

what mods do you have on your car?

 

all it has is a k&n fipk, 3.73s, and diablosport stock exhaust. any ideas???

 

I'm trying to track down the culprit because I am throwing this code now too. My thread is in the ls1 Newbie tech section...https://ls1tech.com/forums/new-ls1-o...eird-idle.html. It seems to be my stock cat, but other's have said post cat 02.

 

yep.. could be the cat itself that's bad, or the rear O2 sensor that's bad...

 

weird part in my situation is the light only comes on when i install the diablo tune. since i installed back to stock i been driving for 100+ miles and no ses light. as soon as i installed the diablo tune, the car runs fine, i get a ses light in about 10 miles. any ideas why that could be happening???

 

id get a hold of diablo IMO

 

What revision is onthis Predator?

There is nothing in the tune that would/could/should cause that code...

 

its a 9vr15. i just got it a week ago. i just ordered the usb connector so i can save my data logs.

 

Subscribed now. Any more news?

 

There was a recall on the cats going bad on the 2000 year LS1s. I know because my T/A had the passenger side cat go bad. Good news, it is replaced for free up to 12 years, 120k miles I think, not too sure. But what could be happening is that your cat is GOING bad, and is barely able to make it on stock tune, but the Diablosport is changing your fuel trims and dumping enough fuel to where the cat can't handle it on it's last leg. To absolve my issue, I installed O2 sims for about 2 months, then went LTs and ORY and had the rear O2s tuned out. But since you're in Cali, look for the recall (or whatever it is) on the cats turning sour. If the tune was really an issue, it'd trigger both sides. Hope I could help you out.

 

that sounds like a very good possibility, that car runs great and runs hard with the diablo tune!! i just get the code and dont want to drive it like that. im thinking of putting the tune getting the code, putting it back to stock, than taking it to see if they will replace the cat. i found the tsb. its 10 yrs and 100k miles. im also going to data log to see what it shows.