Passing Smog Test

[78 Big10 454]

I know in the past, many Board Members have passed along tips on how to prep your Square for a smog test/inspection. I've searched the Forum with no luck. All the required components are in place. Any helpful ideas are greatly appreciated. Thank you!

[83burban]

If the truck has cats: Drive it for over 30 mins before the test and drive it hard right before to ensure that it is as hot as possible. This will lower some of your exhaust gas values

Change your oil right before the test, will remove some of the carbon from the engine and reduce outputs as well

Make sure that your timing is set right, and de-tune the engine a bit by leaning out the jets just a little bit and retarding the timing (double check - not sure on this one personally)

Add some alcohol to the gas tank about a week before the test and drive it like that - will clean reduce some values as well

If your truck fails after this, then run some seafoam through the engine and repeat the steps - will help to clean it up further and might help it to pass

[solidaxel]

[Add some alcohol to the gas tank about a week before the test and drive it like that - will clean reduce some values as well

[/QUOTE]

What ratio gas to alcohol?

[87chevy.com]

my truck had a hard time passing becuase of the tune. all emissions were way below value with the exception of nox... the tune has high advance and there was no way for me to adjust it, so I just waited till the truck was dead nutz cold and retook it. passed no prob. If you fail, post your readings and we can tell you what you need to do to get the #'s down to pass. As an inspector myself, you have a certian number of days for a 2nd free retake
clint

[78 Big10 454]

Many thanks, 83burban and 87chevy. Those were the tips I was looking for.

[sixshooter798]

I recently passed with my 77 350/350.

As stated above, drive the crap out of it before you go in for the smog test. I replaced the spark plugs, wires, cap, and rotor before going in.
Also, make sure all of your emissions stuff is there and you have the timing and such set correctly.
I did not add alcohol to the tank, and I passed with flying colors.

[78 Big10 454]

That's good news sixshooter. This smog test has me so worked up, I may be drinking the alcohol to get over the pre-test jitters.

[tucsonjwt]

I always change oil, air filter, breather element before going to emissions. Also, new spark plugs are cheap and worth replacing before you go through emissions. I just got 16 Champion platinum plugs on sale for $0 with rebate - I keep a couple of sets on hand since I only drive city and they get carboned up quickly - usually change them out before emissions every year.

[solidaxel]

Originally Posted by tucsonjwt

I always change oil, air filter, breather element before going to emissions. Also, new spark plugs are cheap and worth replacing before you go through emissions. I just got 16 Champion platinum plugs on sale for $0 with rebate - I keep a couple of sets on hand since I only drive city and they get carboned up quickly - usually change them out before emissions every year.

.............. Who has Champions for that price in Tucson ?

[78 Big10 454]

OK, fellow Board members, today is my truck's 33 birthday and had her smogged. Due to the helpful tips that I received, I passed with flying colors. Thanks to all of you, my truck and I will have a very Merry Christmas!

[78 Big10 454]

I used STP Gas Treatment in lieu of the alcohol. Dumped three bottles down the carb and two more in a full gas tank. Really blows the bad stuff out of the engine.