11-13-2019, 01:12 AM | #1 |
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CAI>CEL>high LTFT>low Vacuum?
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. |
11-13-2019, 10:16 AM | #2 |
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Drives: 2020 X2 M35i, 2005 Volvo V50T5
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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? |
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11-13-2019, 03:33 PM | #3 | |
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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. Quote:
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11-14-2019, 07:15 PM | #4 |
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Drives: 2020 X2 M35i, 2005 Volvo V50T5
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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. |
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11-14-2019, 11:58 PM | #5 | |
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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. Quote:
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