Almost passed smog test, how to reduce HC in tuning?
03-14-2006, 01:02 PM
#21
Originally Posted by Terry Burger
Quick update: I pulled 4 degrees of timing out, and ran a 5% alky mix, and it barely passed the emissions test. Unfortunatly since I had reset my PCM none of the readiness tests were ready, and I need to bring back a Carb EO # for the AFR heads. This guy didn't seem to care about the PCV or anything else. I'll reupdate this next week when those stupid PCM tests run. It seems taking out timing helps HC (consistant with research I did on google).
T
T
03-14-2006, 01:05 PM
#22
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Well im glad it worked for you but it dosent seem to be very logical that removing timing helped get rid of some of the unburned fuel. Think about it the spark is sent out later so now all the fuel has less time to burn before it is sent out into the exauste stream. The alky is like putting in higher octane making the mixture harder to burn. Could you give me some of the sites that say that removing timing is a good way to lower HC? Did your CO go up with the taking out of timming?
03-14-2006, 01:38 PM
#23
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Well the theory is probably that if you wait until the piston is closer to DTC everything is closer together and will burn more completly. Maybe it doesn't work and this test was a fluke... 
I'll try to find those readiness DTC's today and retest.
I'll try to find those readiness DTC's today and retest. 
