Hi guys, I have a 2006 Mazda 6 MPS with a few basic mods.
I am asking for help in diagnosing an issue that I am currently having, as many of you OZMPS forum members have a lot more experience with this platform than myself. Please excuse me if something I write or try to explain doesn't make sense, this is one of my first posts and I am relatively new to the wonderful world of car modifications.
I am experiencing a lean issue when going WOT (see 3rd WOT to 5000rpm datalog). This issue occurred in my current map and also in a Cobb OTS tune stage 2(95 DP, SRI, TIP) that I trialed to see if the issue was due to a tune for a slightly different MAF housing. The Lean AFRs occur in all gears. The Measured AFR is varying quite a bit from the commanded AFR, (around 12.3-12.7 measured vs 11.3-11.7 commanded)
I was running the S-OTS tune for 5000km plus without any issues, except for a bit of a boost spike which I guess is normal for an OTS tune.
The issue first came about when I recently installed my CS Air box (ecu was reset due to having to remove the battery), as soon as this was installed the AFRs became lean.
I have also noticed the AFR became rich after letting off the throttle or during shifts. (see datalog 1)
3rd WOT to 5000rpm.csv
Cruising.csv
datalog1.csv
Mods:
-Cobb AP runningS-OTS stage 1 95 tune
-CS SRI,TIP and Airbox
-Custom 3 Inch dump pipe with 100 cell hi flow cat
-Autotech hpfp
-ITV22 Sparkplugs
-JBR 80a Rear and Transmission mounts
-JBR short shift plate
-VVT and timing chain replaced as a preventative measure
Troubleshooting/Fixesalready tried:
-MAF sensor cleaned using "CRC mass flow sensor cleaner"
-MAF sensor o-ring replaced. Ensuring MAF sensor is correctly in place when reinstalling.
-Very carefully reinstalled the intake system. Thoroughly checked all clamps,ensuring they were on correctly, and all hoses leading to waste gate,boost solenoid, crank case and BPV (can't think of any others off the top of my head). Also checked for any cracks or excessive wear marks in any hoses/pipes. Spent a total of 4 hours going over everything.
-Tried running the car without the Air box to see if the issue went away, but was unsuccessful.
Otherpoints of interest:
-I use Nulon 10w-40 HTFF oil and change it regularly.
-I only use BP 98 fuel, or United P100.
-I am currently experiencing a small amount of smoke from the exhaust after idling for a while, or while in slow moving traffic. The lean AFR were occurring well after the smoke started appearing. I realise the cause of the smoke is my stock turbo has oil leaking past its seals. (plan on upgrading to a bigger turbo soon)
-The dump pipe I had fitted was from Best Mufflers in Sydney, the bloke does amazing work. I had this fitted approximately 5000km ago and have never had any CEL or issues with it. He showed me a lil extra he had fitted to the 2nd O2 sensor, which he explained as altering the signal for the emissions side of things. He said it shouldn’t alter any AFRs or affect the actual running of the vehicle ( I presume these things would be controlled by the primary O2 sensor)
-The MAF housing has no air straightener
-EGR plug is disconnected following RAYDs guide
-Have not had any CEL, except from the EGR plug.
Summary:
So basically everything was working perfectly (or near enough to it) for awhile,then when I fitted the air box things went a bit not so perfect. This could merely be a coincidence.
I am starting to think whether my BPV might be leaking and in need of an upgrade, or maybe if my MAF sensor or primary O2 sensor has messed up. If it was the latter however I assume that my MAF and AFR readings would be fluctuating greatly, and the car would run like poo, or plain not even start.
So I am asking for the help of those of you with more experience and a better understanding of these cars, to help resolve my little issue.
Thank you for taking the time to read my thread, any feedback/help offered is greatly appreciated.