Emission test failed

kwren · #1 10-30-2008, 05:05 PM

Too much unburnt fuel out of exhaust.

Any ideas?

Blacky · #2 10-30-2008, 05:56 PM

O2 sensors come to mind first. MAF sensor perhaps?

SoCal LS-L · #3 10-30-2008, 08:19 PM

Run a good fuel system cleaner through a full tanks worth of driving, and if your plugs are old or you are unsure of their age/condition, replace them. Also check your air cleaner and find any possible vacuum leaks. Good luck

kwren · #4 10-30-2008, 09:50 PM

All great components suggested above. How is the best way to check for a vacuum leak... ?

Thanks to all,
Keith

XT6Wagon · #5 10-30-2008, 09:50 PM

also before you get tested drive it till its warm, then drive around for a few in a gear or two too low so the RPM's have to stay high. The point is to get the cats HOT HOT HOT so they work the best.

SoCal LS-L · #6 10-30-2008, 11:27 PM

A good way to check for vacuum leaks is to use about a 2 foot length of 1/2 or 5/8 inch hose and put one end to your ear and the other use to probe around your vacuum lines. If you hear a loud constant hiss, bullseye. Id also try driving a long distance at freeway speeds to burn out combustion deposits (if you do mostly local driving), and dont forget to run the fuel injector cleaner thru. Dirty injectors can cause too much unburnt fuel since they squirt instead of spray, causing incomplete combustion, or something is causing the computer to enrich the mixture too much, such as a vacuum leak or sensor malfunction. No check engine light on?

SoCal LS-L · #7 10-31-2008, 03:10 PM

Oh yeah, was it failed on idle or revving? Sometimes you can get a cool tech that will let you rev the engine slightly at idle up to the limit on the tester to pass you at idle if thats the problem. Not sure if your emissions procedure is the same as here though.....

ZMan · #8 10-31-2008, 04:25 PM

You might want to try this - I haven't used it, but you can read reviews at this site, all positive.

http://www.amazon.com/Guaranteed-Pas.../dp/B0007N1ZPY

wantafastsvx · #9 10-31-2008, 08:01 PM

Probably a silly question since you have emissions to test but is the exhaust factory? Still have all three cats? Just a thought again probably a moot point

kwren · #10 10-31-2008, 11:29 PM

Quote:

Originally Posted by wantafastsvx

Probably a silly question since you have emissions to test but is the exhaust factory? Still have all three cats? Just a thought again probably a moot point

Got it all!

kwren · #11 10-31-2008, 11:30 PM

Quote:

Originally Posted by ZMan

You might want to try this - I haven't used it, but you can read reviews at this site, all positive.

http://www.amazon.com/Guaranteed-Pas.../dp/B0007N1ZPY

Tried it twice

kwren · #12 10-31-2008, 11:31 PM

Quote:

Originally Posted by SoCal LS-L

Oh yeah, was it failed on idle or revving? Sometimes you can get a cool tech that will let you rev the engine slightly at idle up to the limit on the tester to pass you at idle if thats the problem. Not sure if your emissions procedure is the same as here though.....

2500 rpm.....

kwren · #13 10-31-2008, 11:33 PM

Quote:

Originally Posted by Blacky

O2 sensors come to mind first. MAF sensor perhaps?

new o2 sensors twice (subaru)

Cleaned 2 MAFs twice!

kwren · #14 10-31-2008, 11:35 PM

Quote:

Originally Posted by SoCal LS-L

Run a good fuel system cleaner through a full tanks worth of driving, and if your plugs are old or you are unsure of their age/condition, replace them. Also check your air cleaner and find any possible vacuum leaks. Good luck

I use fuel system cleaner about every 2-3 fill ups

kwren · #15 10-31-2008, 11:35 PM

Quote:

Originally Posted by wantafastsvx

Probably a silly question since you have emissions to test but is the exhaust factory? Still have all three cats? Just a thought again probably a moot point

exhaust system is factory.