bigblue15

Hey guys,

so the other day i took my car in for inspection, it took 3 times to pass. the first time it said that my o2 sensors and sensor heaters were "not ready", i just didnt know why because i had bought a MAC intake for it, and that brought on the check engine light because it knew too much oxygen was coming in, so i bought a tuner and cleared the trouble code because i figured the tune would fix it and didnt want to see the engine light anymore, did the tuner not fix that? because i went home after that and put the factory intake and tune back on, went back and the o2 sensors passed but this time the catalyst and evaporative system (whatever the hell those are- btw the guy at the inspection place didnt even know either, i asked him) didnt, so i drove it like 15 miles and took it back then the car passed inspection (thank god)

i would really appreciate some feedback as to why the tune didn't fix the o2 sensors, or what was wrong...thanks guys!

MustangBradley

All the O2 sensors do is tell the computer the oxygen content of the exhaust gases. The computer then makes all of the necessary adjustments. If you are getting codes that point to the sensors, they could be bad.

bigblue15

what about like a racing sensor or somethin? i've got a friend that has one and it works pretty well for him, they're just a lot of money

Detailer_Dave

You have to complete XX number of "drive cycles" for the computer to show "Pass" on a scanner, or in this case, inspection. If the drive cycles arent completed, the computer will give a readout of "Not Ready" and the reasons. Your car will fail inspection if "Not Ready" shows up.

JCstang01

Just a thought...

Did you have the battery disconnected at any time in the couple of days leading up to the inspection? Such as when you swapped out the CAI...

If so then that was the issue. When you disconnect the battery it resets the computer and as Detailer Dave stated you must drive the vehicle through a certain number of cycles for all systems to clear the "not ready" status.

The "cat" and "evap" systems are typical offenders of this when the battery has been disconnected or replaced.

bigblue15

nah i didnt, the inspection guy asked me the same thing but i didnt

Rocket Ray

Did you buy an inspection friendly tune? I thought I did but it still turns off the O2 sensors in the rear, and then fails inspection. I too have a MAC intake, but come inspection time I put the stock intake and stock tune back in, drive for 75 miles and then take it in, then after I get my sticker I put the MAC and tune back in.

bigblue15

hmm im not sure if i did or not, regrettably (i guess not, since it didnt pass)...im actually looking into purchasing a new tune from brooksspeed so ill have to get him to hook me up with one of those...and on another note, with your MAC intake do you use the stock MAF housing?...cuz i just bought the intake from a guy and figured it's the same thing, but i read recently that all the power comes from that, rather than the intake itself

Rocket Ray

The MAF housing is built into my MAC intake tube. From what I understand, the thing that makes this intake work is the plastic ring on the inside of the air filter, where it passes into the metal tube. My mass air sensor is the one that came with the car. I have a 93 octane tune from VMP. I am fairly happy with the performance, just not the fact that I have to take it off once a year to pass inspection, especially since I put the car up for the winter. I may try a tune from Brenspeed this spring if they offer one that will pass NY state inspection.

There was a comparison of most of the cold air kits on Mustang5.0 that can be found online. The MAC came in second place I believe.

Boss_Hotrod

The reason you didn't pass is because you cleared the CEL. When you clear it the computer not only deletes the DTCs but the readiness codes as well. Just putting on an aftermarket intake shouldn't have cause the CEL unless you had lean codes p0171 p0174. Which would most likely be due to a vac leak.

In the future when you need to set readiness codes for a NCSI (NC state Inspection) do this. Let the car warm up (get the cat good and hot) drive the car down the interstate at at least 50 mph for 2 minutes. That sets the codes (except evap since that takes forever to set.)