Today I went for the dreaded Emissions test and failed. I was smart enough to record the session though. HC failed by 36, CO failed by .26, and NO failed by 261.

The NO is what is puzzling me.

Last year it was really high until I fixed the EGR, so I figured the EGR might not be quite right again. When I looked at the datamaster run during the test, the EGR DC only went as high as 68.6 and this leads me to believe that the EGR was not commanded fully open.

This would seem to me to be a glitch in the programming but after reviewing the options in Tunercat Im not sure what to change.

Any Suggestions?

 

Was it cool (around 40*F or less) when you tested and do you have a relocated MAT? If so, one problem may be you need to lower the "EGR Enable Temp". Stock, it set to disable around 40*F. No one really knows the true "algorithm" for this particular temp setting (it's not standard) so just set the "counts" to something lower.

Also, set the TPS% enable/disable lower. This will will help engage the EGR sooner and more completely. At the stock settings, I found the EGR could go into "partial" operation if I was cruising at light throttle under 6% TPS.

 

It was cool, about 32 Deg. Also, the TPS was right about 6%. Ill try your suggestions. Thanks!

About the MAT, Im not sure where Its supposed to be, But I think its on the bottom (rear?) of the plennum.