One problem fixed, another created

[BuickMike231]

Ok so I just posted yesterday about the code 45 and failing on the NOX. I turned the fuel pressure down a little bit, back to the stock chip range and got rid of the code 45 so I figured I was good. I took it back to get tested today and it killed the NOX, it was way within the legal range but now my CO was too high and failed. Is there some type of sweet spot with the fuel pressure for this? The CO passed fine the first time when I was way over on NOX, now I'm way under on NOX and a little high on CO. Any thoughts?

 

[Danster]

I kind of went through the same thing about a month ago down here in TX. I failed the CO portion. I went ahead and changed out my 02 sensor since I had not done that but also put in about 12 ounces of Lacquer Thinner to about 1/2 a tank. Passed with flying colors.

Might want to try that. I left my fuel pressure in the 42-43 range.

Dannyo

 

[bmackinnon]

Varying fuel pressure (within reason) will make NO difference, as the ecm is compensating based on O2 sensor feedback via the BLM's/INT's. Make sure the car is good and HOT when you run the test.... makes the cat work much better.... if you have a 160 thermostat, swap it for a 180, drive the car on the highway several miles in 3rd gear on the way to the test to get the cat real hot, leave the car running when you get there, and give it another shot..... should do the trick....

EDIT: OH!!! and for christ's sake!, you can't run the stock chip with 42 lb. injectors!!!! Will make it run WAY too rich!!! Put the tweak back in, set the fp to 43psi, and do the above... you should pass w/flying colors....

 

[BuickMike231]

Sounds good and thanks for the heads-up on the injectors....kind of dumb on my part:redface: . Yeah I think that would make alot of sense. Thanks for the advice, I will let you know what happens!

 

[BuickMike231]

Ok I finally got it to pass, thanks for the advice guys! I put the TT chip back in, put fuel pressure back to around 43psi, changed the oil, and threw some Iso-Heet in there for good measure. The car passed no problem. Thanks again for the help!!