thanks, further notes
My car is an automatic, so no EGR.
Test Results:
........Limit..03'...01'.....99'
HC....62....16....16.....23
Nox..456..695..618..342
In January 2003, the guidelines for the test were tightened on us. where 618 passed in 2001, under the new fudge factor I no longer pass!!!!!!! I found out this was changing last December, and should have done the test then :-(
My NOx jumped between 1999, and 2001 - during this period, I installed a "gutted" larger style MAF. I might be able to reduce by changing back, but won't likely give me what I need.
I am going to look for intake/PVC leaks, and try to see if I can determine any difference in the 02 sensor signal if I create, then stop intake leaks, this will tell me if I am making much improvement.
My 1995, with very low miles - that HAS EGR - read ZERO NOx.
From reading the "Ford Fuel Injection and Electronic Engine Control" book, I don't believe our cars have a 3 way catalytic; there is not air pump, to add air to the cats in our car, which looks as if it is the only visual difference.
Also according to this manual,Nox increases with spark advance above 20 degrees BTDC. Maybe pulling the octane plug and knocking the timing back might gain something as well, what do you think?
I really don't think 02's are going to make any improvement in this situation. Maybe I should swap CAT pipes with my 95....
Furthermore, I cleaned the injectors when I did the head gaskets.
Do you think "blow by" would have any impact on N0x? I suspect it would only show in HC's???
If I could get it to run a bit richer, I have lots of HC room to spare, maybe this is how I can pull the combustion temperature down a bit hmmmmm