Alright,on November 6th, I installed berk tp's, install went great. About 150 miles later, I got cat codes, no big deal, got some spark plug antifoulers, drilled them out(but not all the way through) with a 15/32" bit (might be able to use 29/64" for hr engines to avoid Brillo? But that's another thread idea) and now I don't have a cat code problem.
This was done on the 10th with the first oil change in my hands with rotella t6(did a lot of research on oil) and a Mobil filter, half can of seafoam was run in the old oil for about 30 min before the drain, other half in the tank. Another bottle was run through the intake and soaked for a few hours before starting. Since then I had no problem, until Saturday the 17th, when the cel came back on(ran about 300mi from the 10th-17th) This time the light is for a P1273, b1s1 reading lean. I cleared it on Monday, came back yesterday, cleared it again, as its back again. It takes about 40mi with 2-3 cycles to come on. To me, it sounds like an O2 sensor, since it comes back so fast and is only one bank, and took so long after the test pipes and oil/intake cleaning. My uncle, whom I work with(I'm an apprentice), is a 23 year licensed mechanic says the tp's are more likely the cause.

I was wondering what you guys thought of this? I haven't really seen anything on here(searched last night) that had any information about the p1273 being associated with installing test pipes. However, I have heard about them running more lean than having cats, but nothing about lean codes.

Info on the car.
2005 35th anniversary edition, 6spd manual(rev-up)
It is an American car, I'm in Canada, only mods are the berk tp's and a k&n drop in. It has 71k miles,

 

Have you tuned it yet?

 

Woo you are from Pickering? Don't see many other Z's around here unless they are from Toronto and area.

I don't really have any input on your issue, I just installed Berk HFC's and I am not having any issues with them (about 1000mi later)

 

Its a toss up if they'll throw the codes or not but its very common with HFC and test pipes.
Uprev tune will fix it and make your car 100X more fun to drive

 

no tuning yet, hopefully that will be coming in the summer/fall
as i said, the code that im getting now is a lean code on bank 1, not a catalyst below threshold. tomorrow, im going to check the intake tube connection to the TB to be sure i reinstalled it correctly and it hasnt partially fallen off or leaked

im thinking about dumping the program in the computer and letting it relearn itself. was also thinking about swapping primary o2 sensors, if possible? from side to side to see if the problem moved with the suspected bad sensor.

another idea, that i dont really want to do(yet), is to buy an aem a/f meter kit and monitor each bank on separate drives in similar conditions


ps. yes, i am from pickering. i dont see many z's out here at all, either!

 

I'd reccomend you get a tune much sooner then that. Every car is different but without a tune your car could be running dangerously lean are certain rpms.

 

I know a tune would be best for it, of course, but only if both o2s are working correctly. As I said, it's only showing lean on the one side and it was fine for a week after I did the CPU dump, which is more than enough time for the computer to learn. I wanted to wait for the tune so that I could get all of my bolt ons prior to tuning and not have to retune.
If it was running lean, wouldn't it throw codes for both sides? :s it's only throwing bank one, over and over :s is really like to hook up the modis and go for a drive, monitoring the o2s, but I haven't had a chance and probably won't for a while :/
Tomorrow I might be able to swap the sensors side to side, hopefully this will confirm my susspision of the sensor, if code doesn't move, maybe I'll have to do a tune?

 

alright, so, i think i figured it out.

car is throwing lean codes after the carbon clean from the intake because of the test pipes. i read somewhere a great theory of the test pipes not being restrictive enough to "hang up" the unburnt fuel around the A/F sensors and making the ecu think that the car is lean. the ecu only thinks this AFTER the carbon cleaning because of the increased airflow through the intake. now, i dont know if my MAF is dirty, but i will be checking this tomorrow at work, to be sure that it is reading properly(i hope it is slightly dirty to clear up the CEL for good)

i did an ECU relearn last night and the care certainly feels more smooth and like it has more power than before(now i know what you guys love about the 2nd gear pull). i didnt think anything of the relearn untill i drove it afterwards; it feels like a whole new car. the code came back after a long drive, but no CEL yet(at least 4 cycles since the relearn). this may have helped clear the light for good, but i doubt it, since the code has come back once, already.

now, i also read a good theory on intakes, in general. it said that cars are tuned from factory to run slightly lean(im assuming for fuel economy) and that aftermarket intakes(short ram or JWT style) are sometimes designed to create turbulance around the MAF to "trick" it into thinking that the car is getting more air than it is and in turn dumping more fuel into the system.

in my case, all i have is a k&n drop in with a rev-up airbox which creates a very direct, low turbulance flow over the MAF. this direct flow with the added test pipes allowing the air to fly out of the cylinders and past the A/F O2 sensors, quicker than with stock cats, would make the computer believe that it needs to richen the mix to bring it back within specs.(id really love to put a wideband in, if i could, so the AEM uego is looking better and better...)

if the turbulent air theory is true in practice, then i may be able to correct my condition with a pop charger or of the like. i know that was a lot to read, but i was wondering what you guys thought of this? and before you ask/suggest, no, i havent tuned, nor do i plan on it yet. finances, with christmas and all, arent looking like ill be able to tune for a while, even though i know its a surefire way of eliminating the problem. im just hoping that this all makes enough sense in theory and practise to work.