I've failed for 3rd time. This time I had a cat in place. We tried to lean the mixture out as much as could be done safely but it had no affect on the hydrocarbons. In fact, the hydrocarbons haven't changed even after installing the cat. On the previous test, we had a richer mixture which caused the hydrocarbons to go up even higher. Do you guys have any advice on which way I can go with the tuning?

 

Not sure on the subject because we haven't had emissions here in Florida for years , but have you tried playing with the timing? I am guessing you have already checked out you EGR and AIR controls. Has anyone played with those to help pass?

 

I would try a few of things..

Increase the idle RPM.

Give the idle PE a try. This is where you set TPS to engage PE mode at 800-1200 rpm to 0% and then add the WOT blocker to keep the BLMs steady at 128. Just keep decreasing the variable in the PE chart at 800-1200 rpm till you are satisfied. I have found this to be around -18% or where the O2s are hanging down in the .05x mV range.

I guess a last resort would be to disable closed loop and then in the open loop AFR table try and lean everything out by 10 points(ex. 14.7 afr increased to 15.7 afr). Use extreme caution with this suggestion!

 

I just passed today. I also failed. Our limit is 220 I had 435.
With Ion's help I increased the idle to 850, increased the temps and locked it in open loop and adjusted the A/F tables for open loop.
I passed with 145 HC. I had my cutout open just a little both times.