ZeroNZ
Greenie N00B Member
Year/Make/Model: 2006 Mazdaspeed Axela
Mileage: 205,000km/127,000 miles
Location: Invercargill, New Zealand.
Concern: DTC lamp and black smoke from exhaust under boost/fuel economy
DTC's: P2178 - System too rich off idle
Modifications: HPFP, High flow turbo, FMIC, aftermarket exhaust, running 100 octane (91-94 US octane).
ECU/Tuning Software: Versatune - Purchased with locked tune and no local tuners
Tuner: N/A
Is the concern intermittent? No, but it can take a day or two after code clearing to return.
Can you duplicate the concern? Yes.
Recent Repairs: None.
Correction:
For context I am an Auto Electrician and have carried out a few tests to see if I can determine faults.
Carried out a smoke test to see if there is a leak, none found. Monitored live vehicle data with scan tool and found fuel pressure to be within spec, most data seems to be correct for idle according to known good data I have found.
Only thing I can fault is the MAP sensor may be faulty but scaling seems to be correct. MAP sensor is reading 4psi at idle and 28psi at peak boost. With a calibrated vacuum/boost gauge the car is pulling between 20 and 22 inHg at idle, and peak boost is 18psi. It would make sense for the vehicle to be over fuelling if it is thinking there is 10psi higher boost than there actually is and is trying to compensate. The B1S1 O2 sensor is reading flat at -128mA. LTFT is sitting at -20% and short term fluctuates between 0- -20% depending on driving condition. I've checked all wiring and connections and eliminated everything bar replacing parts.
Does anyone have any good data on MAP sensor voltages at pressure readings? Or have any other ideas of what I could check? I can just replace suspected parts but I would much rather eliminate by testing.
Thanks guys!
Mileage: 205,000km/127,000 miles
Location: Invercargill, New Zealand.
Concern: DTC lamp and black smoke from exhaust under boost/fuel economy
DTC's: P2178 - System too rich off idle
Modifications: HPFP, High flow turbo, FMIC, aftermarket exhaust, running 100 octane (91-94 US octane).
ECU/Tuning Software: Versatune - Purchased with locked tune and no local tuners
Tuner: N/A
Is the concern intermittent? No, but it can take a day or two after code clearing to return.
Can you duplicate the concern? Yes.
Recent Repairs: None.
Correction:
For context I am an Auto Electrician and have carried out a few tests to see if I can determine faults.
Carried out a smoke test to see if there is a leak, none found. Monitored live vehicle data with scan tool and found fuel pressure to be within spec, most data seems to be correct for idle according to known good data I have found.
Only thing I can fault is the MAP sensor may be faulty but scaling seems to be correct. MAP sensor is reading 4psi at idle and 28psi at peak boost. With a calibrated vacuum/boost gauge the car is pulling between 20 and 22 inHg at idle, and peak boost is 18psi. It would make sense for the vehicle to be over fuelling if it is thinking there is 10psi higher boost than there actually is and is trying to compensate. The B1S1 O2 sensor is reading flat at -128mA. LTFT is sitting at -20% and short term fluctuates between 0- -20% depending on driving condition. I've checked all wiring and connections and eliminated everything bar replacing parts.
Does anyone have any good data on MAP sensor voltages at pressure readings? Or have any other ideas of what I could check? I can just replace suspected parts but I would much rather eliminate by testing.
Thanks guys!
