Author Topic: Failed CA smog. But no errors on stomp test (Read 3348 times)

Bfdm_mexi · « **on:** March 28, 2011, 08:38:36 PM »

All my numbers were under except the 15mph HC (max 124 / meas 167) and NO (max 815 / meas 1096). I changed plugs today and air filter tomorrow in hopes of bringing more air into engine and more spark to burn off any extra fuel at lower speed. Should I go out and buy an O2 sensor? I did the stomp test and it passed with a 1444. Should I do the stomp test after it's already warm?. I've seen other posts but none with numbers like mine. A little help is much appreciated. Btw I have a 318is coupe 1991.

DesktopDave · « **Reply #1 on:** March 29, 2011, 06:14:51 AM »

I've had a lot of 1444 readings...my favorite was when the car wouldn't start. Guess what it was? Yup...1444. Cold or warm shouldn't matter.

How old is the O2 sensor? If it's more than 4-5 years, it's time to replace it regardless. Check the car very carefully for vac leaks, they can lean out the mixture. Does the car warm up properly? Check the temp sensors (block & AFM), they're critical for warm closed loop running.

High HC might be due to the plugs/wires/coils. How'd the old ones look? High NO is usually due to a lean fuel mix. I'd suggest trying to clean the injectors with some Techron or SeaFoam.

a930rocket · « **Reply #2 on:** March 29, 2011, 10:36:41 AM »

Did you get it good and hot with some hard pulls just before you went in? I know a lot of guys suggest that.

Bimmer805 · « **Reply #3 on:** March 29, 2011, 10:35:51 PM »

well since these cars have no EGR valve it relies a lot on the cat. when i first got my car it failed for NOX and HC was just a little bit high. i changed my spark plugs, air filter, and oil change( this is only for HC). Now for your NOx more then likely your cat is the problem. But try to go get it smogged again but this time before you pull up to the station. rev it at 2500 rpms and leave it there for about 5 min then pull up and don't turn off the car. you want you cat to be nice and hot. my smogged guy was nice and heated up my cars hot and when he tested it again it passed with flying colors. good luck

dvmotorsports · « **Reply #4 on:** March 31, 2011, 05:15:42 AM »

Go to Kragen and get Guaranteed 2 Pass. Follow the instructions on the bottle. I used it on two separate occasions on my wifes old 318 and it worked both times. This was in California.

Bimmer805 · « **Reply #5 on:** March 31, 2011, 10:56:04 AM »

that G2P wont work if you have a bad cat. but that what the label says

dvmotorsports · « **Reply #6 on:** March 31, 2011, 02:07:47 PM »

Right. But by looking at those numbers, if his cat is bad, it's not that bad. The G2P will bring those down. He is barely over. When I ran it, my numbers dropped by the hundreds in some categories.