Quoting b00st33d:
I just failed my smog test today....
below are the numbers:
idle (815 rpm): HC 139 PPM (120 PPM max), CO 0.26% (1.00% max)
2435 rpm: HC 77 PPM (140 PPM max), CO 0.45% (1.00% max)
I am looking for some tips and what to test to lower the HC's on idle. The car has new spark plugs (BPR6ES) gapped @ .030. Engine oil is between 1500-2000 miles synthetic. The car has tubular O2 housing and 3" catback (aftermarket cat converter). TIA
Do you have a logger?
Knowing the fuel trims would tell a tale, as would knowing the raw o2 values.
... anything else is just "guessing".
Absent any real information, if I had to "guess", I'd say it's possible you have a small vacuum leak ... perhaps the injector seals at the base of the injector, or around the biss screw ...
but guessing won't fix a damn thing.
Gathering the pertinent data will allow you to make informed decisions/changes.
Quote:
You affect the timing through the safc as well. It's part of the air delivery curve when you trick the ecu to see different airflow rates it switches timing maps along with. so leaning it out retards timing in the ecu.
adjusting an safc/piggyback device in an attempt to "lean" it out advances the timing.
... and since the ecu will be in closed loop, it will automatically compensate the afr for the lie you're telling it, leaving you back where you started on the afr ... but with advanced timing.
... that will not help your situation.
My suggestion would be to log the vehicle, paying close attention to the o2 values
Post up what you find.
especially the idle values, (you may not be cycling at idle)
I'd also check/verify/adjust your biss settings and actual timing (go to vfaq for the procedures)
You're idling under the target values for a vr-4, and that won't help your situation.
And finally, I'd check/verify the tps and maf functions (especially the baro and iat)
If the car is even close to stock, it *should* easily pass your emission standards without any fudging if everything is working order.
Depending on the level of your modifications, even heavily modified cars will pass if the tune is correct.
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If you're running a factory vr-4 e-prom ecu, it's set to idle at 850rpm.
It's a little known fact that the ecu tosses additional timing at a low idle (in addition to moving the iac,) so your low idle speed is hurting you much more than you would think.
... find out why it's idling at a lower rpm, fix that problem, and you're probably golden.