Upcoming Emission Test - Do I avoid additive(s)?

[just1guy]

Hey guys,

I've got 2 cars (Mazda6 and Ford Focus) with emissions tests that are due this month. I ran Techron through both last month (at least 2 gas tanks ago) which greatly smoothed things out on the Focus. I am also planning on changing the oils before the tests and was going to add half a quart of SLOB as well. However, after reading up that some additives can cause deposits to leave through the exhaust, I'm not sure about SLOB until after the tests are completed. Any guidance or clarification from you experts would be greatly appreciated.

Thanks in advance...Just1Guy

 

[Quest]

SLOB would only affects your emissions if your engine is burning motor oil.

I would simply go like this:

(1)after running FIC such as Techron,etc. change the motor oil with something fresh.

(2) check and inspect your ignition timing, spark plug conditions, PCV valve (replace it if it's deemed questionable)

(3)fill your tank with good quality gasoline, any octane is fine so long as it meets your minimum octane requirements.

(4) take your car on a highway drive for at least 30mins or so, this is to bring your motor oil, cat converter temperature up over an extended period of time.

Drive to the testing facilities and then go through it w/o turning off your engine.

Good luck!

Q.

 

[just1guy]

Thanks a lot for the itemized "to-do" list. I greatly appreciate it.

 

[psudaytona]

Don't use any fuel adds during the emissions run. Many contain chemicals that will cause the hydrocarbon reading to go up(the kerosene in many adds will cause this to). Before mine I was heavily dosing MMO,lucas, regane, and a couple generic ones from wally world. But I ran that tank down to nothing and refilled the day before the exam with just plain old 87 octane. I aced the test with 37ppm at idle when 220ppm was the limit, and 30ppm at 2500RPM. Considering I drive an old dodge daytona with 183K miles, thats very impressive. Guy at the testing station even mentioned it to me that it was an amazing score for a car like mine.

 

[ewetho]

If they tailpipe your cars then Quest is just about right. Some have seen good results on cars that are borderline with a couple bottles of heat. Not best running but they pass.

 

[andyd]

93 octane burns cooler if NOx is an issue. It is the only time I use it. I passed MA emissions with 1/2 the max allowed NOx on a BMW 528e that had 330kmiles on the engine and the cat.