I really need some advice.

I have a 2005 chevy tracker. It came from the factory with a 2.0 suzuki engine. It has failed emission 3 times for NOx.

6 months ago, had the top of motor rebuilt. Coolant is good, fan is running, car does not over heat.

1 time fail, changed the Cat Converter. I don’t remember the data for NOx

2 time fail, changed the EGR Valve. NOx 1000+

(when I picked the car up the check engine light was on for the 1st time, then the mechanic cleared the code that caused the light. He said it was because of the change of the EGR valve.)

3 time fail, don’t know what else to do. NOx 800+

If you what to pm me --- silence280@aol.com

Any advice you can give will be appreciated.

 

That is from running lean, mechanic have scanner or just code reader?

 

i am really sure he has a scanner. but i will ask him
*he has a scanner

 

Post what the O2 is reading,and when's the last time the MAF has been cleaned?

 

With New CAT Converter


Idle Engine under load


HC ppm 7 7
CO% 0.02 0.01
CO2% 15.2 15.1
CO + CO2% 15.22 15.11
O2% 0.0 0.0
NOx ppm 422 1021
Lambda 1.00 1.00


With New CAT and EGR


Idle Engine under load


HC ppm 3 1
CO% 0.03 0.01
CO2% 15.1 15.1
CO + CO2% 15.13 15.11
O2% 0.0 0.0
NOx ppm 829 365
Lambda 1.00 1.00


do you think it is the MAF? will a bad MAF produce high NOx? i unplugged the MAF while the engine was running and it did not stall, it ran a little better at idle. so i ordered a new MAF and it will be here on the 12th.