Mitsubishi Repair: Emission problem w Lancer, egr valve, carbon monoxcide

Question
Hi Anthony.

I have read your previous answers and you seem to know your stuff. So, here´s a tough one for you.

I have a problem with Lancer 1,5i (catalyzer)and manual tranny. I had the car checked in a shop and the HC value is too high to pass the exam.

The engine used to eat a bit of oil, but I had the valve guides replaced. This had no effect on the HC value. The engine has been regularly serviced and has quite recently been fitted with many new sensors, including the O2 sensor.

MPI adjustment (injector pump adj. and throttle housing clean, the MFI as it´s also known) has been made last time in the spring. My repairman has tried everything, even replacing the cat but that only made things worse, the HC got up.

Now we are at a loss. What could cause this HC to keep high? The engine should be  moderately "clean" so I don´t believe this could be the cause.

The car had a bit of octane clicking too, but I guess this cannot be helped since this model does not have a click sensor. One possible reason we found was the timing seemed to be off.
I believe the ignition timing should be btw 3-7 degrees bTDC, but this car had it in 15 degrees bTDC. This was adjusted but it didn´t help either.

My guess is that could it be so that the timing was (or is now) "180degrees off?" I have seen the engines work if it is but as a result the spark is so weak it has no capacity to burn all the fuel so in a sense the engine runs rich and that causes the elevated HC?
What do you think ? Could this be the reason?
At this point I am open to all suggestions?  

Answer
Arska,
Many times a bad EGR valve, fouled O2 sensor, and/or bad catalytic converter can cause excessive hydrocarbons. Though I would guess the EGR valve is to blame because it's whole job is to maintain the accurate HydroCarbons and Carbon-monOxcide concentrations. If the EGR valve is stuck open, unburnt fuel in the exhaust will continuously pass back into the intake and not be regulated. If that EGR valve never closes at all, your monoxide count will be low, but that can cause your hydrocarbons to increase. Have your EGR valve and EGR soleniod inspected and replaced if necessary. Clean your throttle body and upper intake manifold if you can. It may help.
Good luck!