So about a week ago, I blew the head gasket and replaced it along with all other seals needed to be replaced at the same time. It is 95 dx civic with a d15b8 engine (bought it like that). I took it to get smog today and I failed horribly.

This is the results of the test

%CO2 %O2 HC (PPM) CO (%) NO (PPM)
Test RPM MEAS MEAS MAX GP MEAS MAX GP MEAS MAX GP MEAS
15 mph 1629 9.5 7.5 97 288 138 .59 2.09 .34 731 1992 2574
25 mph 2771 9.7 7.4 62 238 74 .59 2.09 .17 798 1792 2254

On top of the new gasket, I did the usual, new plug, plug wires, oil change. I also only pump 91 and I added octane booster to my tank the day before. Before I took it to get test, I warmed up the cat by driving on the freeway for half hour and when I took it to the smog place, I did not have to wait.

What else can I do to get this thing to pass smog? New cat? New o2? any other ideas?

 

have you tried spraying carb cleaner into your throttle body while someone revs it. it will bog but dont let it die. that'll clean out the engine some. always worked for me. even when smogging a JDM b16 in my 93 GS-R. try it if not get a new cat.

 

That wont hurt any of the sensors? Would that be equivalent of using seafoam? I will give that a shot. Any other ideas?

 

Is the ignition timing set to spec?

 

Yes ignition timing is within spec, it was 17 BTDC. Which I can retard it a little and I will do before I take it to my next test. I dont have a timing light so I did it by ear and I say I did a pretty good job.

 

Well I threw on the new used cat and went to get it tested. I passed. The tech let me use his timing light to adjust my timing.