I am pretty sure there are thousands of posts about the same problem but any help would be helpful.

I have a 1998 Acura Integra Gs-R. I failed smog this past weekend (California). I passed CO and NO but not HC. I know that HC means unburnt fuel. Here are my results

HC (PPM)
15mph- MAX 61 AVE 9 MEAS 92
25mph- MAX 45 AVE 7 MEAS 50

The smog tech said to do a minor tune up. Spark plugs, cap, rotor, wires.
I know my thermostat may be broken because it takes a while to warm up.

My questions are:

1. will doing a minor tune up really drop my HC to a passing level?
2. can my thermostat be a MAJOR factor in HC readings?
3. what other options can I do to drop my HC readings?

Any kind of help would be great! Thanks.

 

stock or modded

 

if your stock then a tune up will help. Also check O2 sensors, and vacuum leaks.

 

Where is timing set? Try advancing timing to 18 degrees if it's not already. 91 octane and a bit of methanol if you can get a hold of some.

 

No#1 It can if you have something wrong like a fouled plug or worn rotor. A weak spark can cause HC too.
No#2 Yes. The ECU uses the ect to switch from open loop to closed loop. If it stays to cool it will never go into closed loop (Closed loop means responding to the sensors output)
No#3 Run a tank of injector/fuel system cleaner thru the system. Air filter could be plugged.
O2 sensor could be the culprit or an exhaust leak before the O2 sensor. Could be the injectors themselves. Could be to much fuel pressure. I could go on and on.

I would fix what we know is wrong before we jump to other stuff.