Passing emissions with F.A.S.T

Night Train

Member
Joined
Mar 19, 2002
Has anyone passed the dyno emission test with a FAST? If so what were your settings? I have a cat only used for emissions runs, 65# injectors, blocked off EGR. I set the A/F ratio to 14.7 and timing was at 18. Here were my results:

Reading Limit

HC 5.85 2.00
CO 50.97 30.00
NOx 3.97 3.00
CO2 440.73 NA

I think the NOx wiil be fine, once I get the HC and CO under control.
 
Just speculating, since my car doesn't have to pass emmissions, but I would first change the temp setting for the fan to come on much later, like around 195 or something. Then make sure it is running in closed loop, and lean out your target A/F. It would be helpful if you have someone that will let you toy with it a little while it is on the dyno. OK, that is just my guess.
Now sum of the smarder peeple, let's here from yous.
 
Night Train said:
Has anyone passed the dyno emission test with a FAST? If so what were your settings? I have a cat only used for emissions runs, 65# injectors, blocked off EGR. I set the A/F ratio to 14.7 and timing was at 18. Here were my results:
Reading Limit
HC 5.85 2.00
CO 50.97 30.00
NOx 3.97 3.00
CO2 440.73 NA
I think the NOx wiil be fine, once I get the HC and CO under control.

As mentioned you want to run the engine hot, so set the fans for at least 195 if not 205.

I'd try about 22d timing at idle, and then ~36d in light cruise conditions.

Then add a can of the guarantee to pass emission fuel tank additive.

Oh, and a fresh change of oil and filter.
 
put 2 cats in series, it will be cleaner than a new car, ask me how i know? :eek:
 
I was wondering if two cats in series might help. Thanks for the tip. I also thought about getting the temp up, but didn't think about increasing the timing. We'll make a few changes and see what my free follow-up test does.
 
In addition to the tips already mentioned I always make sure there's only about 5 gallons of gas in the tank then add a quart of denatured alcohol right before I go to the emissions station...
 
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