Running Lean

S

Stockmzr

Greenie N00B Member
2008 Mazdaspeed 3
240k km or roughly 150k miles

DTC's: P2187, P2006, P2009, P0401

Modifications: COBB SRI, COBB TIP, CPE HPFP, EGR DELETE, VTCS DELETE. Stock Exhaust

Tune: Stock tune, Stage 0, Stage 1+ sf ots

Concern: +20 LTFT at idle, 14.7 AFR at idle but on acceleration AFR's stay around 14-15.

Recent Repairs:
-Cleaned injectors, GB seals, OEM Pcv valve, NTK O2 sensor, OEM purge valve, OEM IM gasket, Fel pro TB gasket, Cleaned PCV breather hose, Valve cleaning, Cleaned MAP sensor, cleaned MAF sensor

Before the flaming starts yes I know I need a pro tune. I don't drive this car hard at all. I've never even gone WOT yet. Main argument is it was running fine a month ago even with the same shit Cobb tune. So I'm ruling out that being the cause. Also my V2 AP sucks balls and won't connect to my computer so I got to spend a lot of $$$ on a whole new accessport and pro tune. Saving up for that.

The car has always had the p2187 lean at idle but it never effected anything outside of idle, before during a pull I would watch STFT go negative and AFR's go to like 10-11 which what I've read is normal.

But now when accelerating STFT goes way positive and AFR ranges from 14-15 which i feel is very lean for pulls even though I'm not going wot.

Did smoke test, found no leaks, vacuum is at -9.8 to -10. When I smoke tested exhaust I found a leak near where the stock dp meets stock catback but that's after the sensors so doubt it's an issue.

Unfortunately no datalogs possible because of shitty V2 accessport not connecting to computer.

Things that I think could be culprits:

-MAF sensor not replaced
-HPFP spill Valve not cleaned
-PRV test tops out at 1624psi

Anyone dealt with something similar? What did it end up being?.
 
Last edited:
It's hard to say without a proper tune for the car. The maps you're running are generic base maps without proper MAF calibrations.

The MAF sensor is going to set the air flow calculation for what's coming into the engine.

Try capping the purge solenoid off and see if that makes a difference in your idle trims.
 
JRR1992 said:
Same problem for me exactly the same
Click to expand...
May be the case, but the reason for the issue could be different requiring different diagnostic and testing. Best to start a thread for your car and give us some info to go on.
Use this template in your own thread...
ENGINE/DRIVABILITY

Year/Make/Model:
Mileage:
Location:
Concern:
DTC's:
Modifications
ECU/Tuning Software:
Tuner:
Is the concern intermittent?
Can you duplicate the concern?
Recent Repairs:
Correction:

Also include logs of the issue

Here is an example of this filled out

Year/Make/Model: 2007 Mazdaspeed 3
Mileage: 156000
Location/Alitutude: Charleston, SC (Sea Level)
Concern: No Boost, engine bogs/misfires once turbo starts to spool, high KR reading of 3.5, fuel trims around -6%
DTC's: P0300, P0301, P0302, P0303, P0304
Modifications: AEM Intake, CS Turbo Inlet, BNR S4 turbo, Turbo XS exhaust/Downpipe, CS HPFP, Treadstone TR8 IC, CX Racing FMIC piping, Turbosmart BPV, XS Power Manifold, Tial EWG, Generic 3 port MAC valve EBCS
ECU/Tuning Software: Cobb Accessport V3
Tuner: Freektune
Is the concern intermittent? No
Can you duplicate the concern? Yes
Recent Repairs: Performed spark plug replacement with generic Champion spark plugs, gap set to .080
Correction: Replaced plugs with proper NGK/Denso Plugs gap set to 0.026
 
UPDATE: So I've been running a "high flow" open filter from Amazon on my Cobb Sri this whole time. I decided today to try putting the old original Cobb filter back into the intake as well as a mesh cover that goes on top of the cone to make it waterproof and it seems to have solved the high fuel trims and lean AFR. Might've been getting too much air before.

But I can't say if this is it for sure though because I only figured it out tonight so will update after driving a few days.

Another thing I did was throw a bottle of marvel mystery oil into a qaurter tank yesterday and ran through it with some hard driving, not sure if that might've also contributed.
 
Well this is weird. So it was working fine but then I switched ots tunes, the fuel trims are still settled at idle but AFR is hanging around 13-15 on pulls again now. Ugh I should've just left it how it was.

But I'm now convinced it's most likely a tune issue. So time to get a new accessport and protune.
 
You must log in or register to reply here.
Back
Top