Smog Check

[joesregalproject]

That doesn't sound right. The numbers sound way to jumpy to be accurate. I would run a bottle of stp fuel system cleaner through the tank (available at pep boys), and take it to a different insp. station. It sounds like that station might have faulty testing equipment.

 

[AlanB]

High NO is generally due to high combustion temps. It could be caused by things like a lean condition, high engine operating temp, carbon buildup, poor EGR, advanced timing.

It just seems really weird that you would be such a big variation between 15 mph and 25 mph, particularly since you improved on the 15 MPH results and the 25 MPH results got worse. Is there another test facility you can try? Is the tester leaving the car in drive, i.e. is there a chance he is at a higher than normal RPM at 25 MPH by leaving the car in low gear? Is it possible that you have a partial EGR blockage, so that you get just enough at 15 MPH, but when you need more flow at 25 MPH you cannot get enough EGR? Could it be that the car is tested first at 15 MPH, which builds up heat in the motor, so that it fails at 25 MPH?

I would definitely check timing to see if it is advanced, and even if it is on, retard it some to see if it helps. May be try a cooler stat, and let the car sit and cool off before pulling into the lanes. Detonation, even if mild, would raise combustion temps in a hurry. Premium fuel might help if that is the case, so would retarded timing.

 

[ve3oky]

Vacuum leak?? With the numbers moving around might be a hole or leak thats growing/shrinking with the engines moment under different throttle responses.

 

[pontiacgp]

how long do you run the car before the test and what grade of gas are you using?

 

[85GPLef41]

how long do you run the car before the test and what grade of gas are you using?

that and what grade cat did you replace the original cat with? I had issues with my old durango passing smog only on NOX with a cheap *ss cat i put on.. the guy i sold it to put a name brand cat and passed! Also is the air pump working along with the CCC system?

 

[714slugger]

I run mid grade 76 fuel and the test shop is only 5 minutes away from my house that got me thinking though about him maybe running it at a lower gear because my shifter is very loose when you pull it down it goes into 2nd gear and you have to move it up one so it can be in Drive how would i go about a vacuum leak to the egr. o and the cat is a magnaflow

 

[pontiacgp]

run low grade fuel for the test, it burns easier so you get less raw fuel in the exhaust and make sure the car is nice and hot when you do the test.