robertbartsch

I have identified the following steps for reducing hydrocarbons for a sniffer emission test:

1. Reduce (adjust) L-trims to slightly negitive
2. Reduce ignition timing - across the board
3. Increase fan temperture settings so engine runs hotter than normal
4. Add fuel injector cleaner and (or) dry gas to the gas tank before the test

Question: Have I missed any obvious things?

Thanks..

wrencher

iTrader: (2)

It's more dependant upon cylinder pressures, & how complete combustion is.

Just remmember Hydrocarbons (HC) is unburnt fuel
Carbon monoxide (CO) is produced by partially burnt fuel (HC) that goesinto exhaust.

Too lean HC's go high, to rich both HC's & CO's are high.

The "right" fuel mixture produces the least emissions, this is what the O2 sensors help the PCM to keep it in fuel control.

Backing the timing off can increase HC's less timing lead in, less complete combustion.
Do you have the timing bumped way up w/edit? Cause then you'll need to back it off.

What exact kind of emission test is this ?

Dont they do OBD testing in NY???

Cal

iTrader: (1)

FWIW, backing off the timing also improves NOx emissions.

robertbartsch

Car is now 100% stock tune, I will tune it for the first time with Edit. Currently, Ltrims are high (+10, +11)

Car has 220/220, 564/564. 112LSA cam and LS6 ported heads @11.2 CR, LT headers with cats....

NY is sniffer test; all parameters except hydrocarbons are way below minimum standards...

Hydro carbons are 73 vs. allowed amount of 60, however...

robertbartsch

I checked the plugs and they have a very light coating of black carbon...nothing too alarming...

wrencher

iTrader: (2)

That 112 lca is prolly hurt'n ya.

Got any way to use a 4 or 5 gas analizer??

Turn your idle up that will help & go from there.