I live here in sunny California so I've got to deal with SMOG.
Well, my numbers up so I stopped messing with the car and put the stock intake peices from the kit back on with the intention of going to the local SMOG test shop to get it through the 2 year ordeal. I've got a SMOG sticker for it so I should be OK as long as they don't look too hard at my ARTech downtube and exhaust. I do have a CA legal CAT in place.
Car is a 91, currently has the stock GReddy manifold, intake piping (OE cross over tube) but the down pipe is a 3" stainless devorced tube from ARTech along with 3" CA Cat and exhaust.
Someone told me I should look at my timing before I brought the car to be tested so I checked it and I was set at about 6 degrees (I had set it to whatever the stock GReddy kit was supposed to be set at when I first installed it).
The same person told me I should set the timing to stock (without turbo) to pass smog so I advanced the timing until it was at 9 degrees figuring it was at the low end of stock but a little low to avoid knock. (I'm running premium gas - 91 octane)
I was driving the car on the freeway and I noticed that my Wideband was showing an AFR around 14.8-15.6 and my Check Engine Light was coming on. Then after a few minutes the CEL would go out and and my AFR would be around 12.3 (I belive that is where it should be)
I am running the stock ECU and currently fuel managment is using the stock Vortec rising rate fuel pressure regulator that comes with the GReddy kit (stock injectors etc).
The last time I checked the CEL flashes it came back with a code 17 so basically its saying the narrow band O2 is out of range. I changed the O2 a few years ago so I'm thinking that it should be OK.
When I first set up the kit my AFRs were fine. Since then I was working on putting in an intercooler and other things to get ready for some track days (eventually I'll add mega squirt, injectors, etc)
So, I've put it back to the stock kit but the only other changes are advancing the timing and installing the custom 3" ARTech devorced gasses down pipe and exhaust.
1) Should I set the timing back down to 6 degrees (Is that the stock GReddy kit setting)?
2) Do you suspect a vacuum leak? (why would it go lean then back to 12.3)
3) Do you suspect the narrow band O2? (Its not very old)
4) What else could I be missing?
I'm already passed my SMOG date by a 2 days but if I can get it to pass before the 20th I only have to pay the extra $21 after that I think they tack on another $10 every 10 days.
Any help would be greatly appreciated.