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Originally Posted by mars

My 92 Civic VX D15Z1 49 state(with EGR) failed smog @ 25 due to high HC. Here are the results:
15mph RPM 2474 CO2 14.3, O2 0.1, HC max 96 meas 28, CO max 0.59 meas 0.03, NO max 859 meas 689 Pass

25mph RPM 2319 CO2 8.7, O2 7.7, HC max 79 meas 146, CO max 0.51 meas 0.02, NO max 798 meas 382 FAIL

Replaced sparkplugs, O2 sensor with new OEM Dealer, ECU P07(eBay- used) Retested

15mph RPM 2452 CO2 14.4 O2 0.0, HC max 96 meas 37, CO max 0.59 meas 0.04, NO max 859 meas 434 PASS

25mph RPM 2209 CO2 9.0, O2 7.3, HC max 79 meas 123, CO max 0.51 meas 0.02, NO max 798 meas 516 FAIL

For both above tests, Timing is 14 BTDC according to smog Tech

I removed the brand new installed spark plugs after about 200 miles and #4 (close to the distributor) looks white and nice, #3 & 2 partially black, and #1 completely black.
Any help is appreciated.

Run a couple of cans of Chevron techron through the fuel system and see if the plugs look better. Fixed a low speed miss in my Sentra in 19 miles. Pretty cheap at Wally World.

regards
mech