[paulosportz]

Hi all.

Need some help/advice before i return my BMS CAI.

Since ive instaled the CAI, i keep getting CEL so i bought a scanner to see what's going on.
The below freeze frame shows LTFT at ide of 25%. When driving the LTFT drops to 0. Vacuum at idle is -3 which is very low? This doesnt change when driving.

I don't have any other engine mods and car is less than 3 years old.

Is the CAI causing the high LTFT and low vacuum readings?




Freeze frame report generated by Torque for Android
================================================== =======

Vehicle VIN: WBAHS720605E81068
Vehicle Manufacturer: BMW
Vehicle Calibration ID: 3BDD3A98
ª

Freeze frame information:
------------------
Fuel Status = 0 byte
Engine Load = 10.196 %
Engine Coolant Temperature = 39 °C
Fuel Trim Bank 1 Short Term = 3.125 %
Fuel Trim Bank 1 Long Term = 25 %
Intake Manifold Pressure = 13.198 psi
Engine RPM = 831.5 rpm
Speed (OBD) = 0 km/h
Timing Advance = -3 °
Intake Air Temperature = 21 °C
Mass Air Flow Rate = 3.02 g/s
Throttle Position(Manifold) = 14.902 %
Run time since engine start = 55 s
Fuel Rail Pressure = 1,665.033 psi
Fuel Level (From Engine ECU) = 17.647 %
Barometric pressure (from vehicle) = 14.359 psi
Voltage (Control Module) = 14.32 V
Engine Load(Absolute) = 19.216 %
Commanded Equivalence Ratio(lambda) = 1.001
Relative Throttle Position = 4.314 %
Ambient air temp = 20 °C
Absolute Throttle Position B = 14.902 %
Accelerator PedalPosition D = 14.51 %
Accelerator PedalPosition E = 14.902 %


End of report.

[//TMT]

Is the car running poorly? What is the CEL code?

Reason I ask is because some of the numbers really look odd. It's a freezeframe from a cold engine (39C) at idle (831rpm), so that in itself is a little bit nonrepresentative. But some of the others are really far out of whack:

- LTFT 25% - should pretty much never be that high, and then it drops to zero, LTFT is LONG TERM fuel trim which changes slowly
- Manifold vacuum -1.2psi - (13.198 MAP - 14.359 Baro) which is normal at idle but far off the value you show in Torque
- Fuel rail pressure 1665psi - yowza

I'd be inclined to not trust these readings without digging deeper. And I absolutely don't think the CAI could cause them to be so extreme.

Have you tried reinstalling the original intake to see if they change?

[paulosportz]

Car runs fine. TBH, if it wasnt for torque, I wouldnt suspect anything is up. The CEL was for P0171 - System too lean.

LTFT definitely drops immediately once there is load. But pops back up to 20%+ on idle or closed throttle. What would this mean?

Isnt vacuum suppose to read over -20 mmHg?

I will put back stock intake tonight and see what the results.

Originally Posted by //TMT

Is the car running poorly? What is the CEL code?

Reason I ask is because some of the numbers really look odd. It's a freezeframe from a cold engine (39C) at idle (831rpm), so that in itself is a little bit nonrepresentative. But some of the others are really far out of whack:

- LTFT 25% - should pretty much never be that high, and then it drops to zero, LTFT is LONG TERM fuel trim which changes slowly
- Manifold vacuum -1.2psi - (13.198 MAP - 14.359 Baro) which is normal at idle but far off the value you show in Torque
- Fuel rail pressure 1665psi - yowza

I'd be inclined to not trust these readings without digging deeper. And I absolutely don't think the CAI could cause them to be so extreme.

Have you tried reinstalling the original intake to see if they change?

[//TMT]

My suspicion is that the MAF location might be affecting the air metering. But I still think those values in Torque are semi-bogus. Will be interesting to see if the behavior changes back with the intake.

Vacuum can vary in a wide range, there is no real floor or ceiling with a turbo engine. But note mmHg is not what Torque is displaying.

[paulosportz]

I think you are correct. The location of the maf in the new housing is not positioned in the same spot as stock. I took the filter off last night and put the box back in. Drove it this morning and LTFT dropped to under 3-5% at idle/low load and under 10% at high load.

Such a pity because the intake is awesome.

Originally Posted by //TMT

My suspicion is that the MAF location might be affecting the air metering. But I still think those values in Torque are semi-bogus. Will be interesting to see if the behavior changes back with the intake.

Vacuum can vary in a wide range, there is no real floor or ceiling with a turbo engine. But note mmHg is not what Torque is displaying.

[//TMT]

That's a shame. Can you post a picture of each, showing the possible difference? Maybe there's a tweak, it doesn't take much.