Browndog said:
I'm also getting codes 33 and 34. I'm sure one or both is related to me unplugging the MAF.
You're probably correct about the codes and unplugging the MAF. Unplug the orange wire near the battery to reset the ECM, then check for codes again. Does the 02 reading go up and down? At idle it should fluxuate as the ECM uses 02 volts to correct for rich and lean. The health of your 0-2 sensor may be suspect.
The popping and hesitation you describe can be caused by spark or fuel issues....You'll have to go through and check each of the system components if the codes don't point you in the right direction....It happens to the best of TR's
If you have a code 33-34 or 44-45 after resetting the ECM, the MALF info is below (since you're at work, you may not have this stuff at your fingertips).
lee
Thanks to Turbolink for the list below.
CODE 33
Trouble Code 33 indicates that the Mass Air Flow (MAF) sensor is reporting more air is entering the engine than makes sense based on RPM and TPS. The MAF sensor produces a frequency output; around 30 Hz at idle to 150 Hz under acceleration. The frequency varies proportionally to airflow. The ECM monitors the frequency and thus determines airflow into the engine. Typical idle MAF is 5 to 7 grams per second.
The conditions for setting this code are:
no Code 21 or 22 (TPS Error) present, and
the air flow reported is > 40 grams per second, and
TPS indicates < 10% throttle position, and
the engine speed is 1400 RPM or less, and
the above conditions exist for over 5 seconds.
Typical causes for this code include:
1) Faulty MAF-to-ECM connection
2) Exceedingly noisy spark plug wires
3) Poor routing of MAF harness (i.e. near coil packs)
4) Maladjusted TPS sensor
5) Defective MAF sensor
6) Defective ECM
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CODE 34
Trouble Code 34 indicates that the Mass Air Flow (MAF) sensor is reporting less air is entering the engine than makes sense based on RPM and TPS. The MAF sensor produces a frequency output; around 30 Hz at idle to 150 Hz under acceleration. The frequency varies proportionally to airflow. The ECM monitors the frequency and thus determines airflow into the engine. Typical idle MAF is 5 to 7 grams per second.
The conditions for setting this code are:
no Code 21 or 22 (TPS Error) present, and
the air flow reported is < 4 grams per second, and
TPS indicates 10% or more throttle position, and
the engine speed is 1800 RPM or higher, and
the above conditions exist for over 5 seconds.
Typical causes for this code include:
1) Faulty air ducting to or from MAF sensor
2) Faulty ECM-to-MAF connections
3) Poor routing of MAF harness (i.e. near coil packs)
4) Maladjusted TPS sensor
5) Defective MAF sensor
6) Defective ECM
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CODE 44
Trouble Code 44 indicates that the O2 sensor is showing a persistently high exhaust oxygen content (lean), despite the efforts of the ECM to increase injector on-time (thus increasing fuel delivered). Integrator and BLM numbers may indicate > 128 by a substantial margin.
The conditions for setting this code are:
no Code 33 or Code 34 (MAF Error) present, and
the O2 sensor voltage remains below 250 mVolts, and
the ECM is in Closed Loop control, and
the above conditions exist for more than 50 seconds.
Typical causes for this code include:
1) O2 sensor defective or lead shorted
2) Lean injectors (dirty or blocked)
3) Water in fuel
4) Exhaust leaks upstream of O2 sensor
5) Fuel pressure or volume too low
6) MAF sensor reading lower airflow than is actually present
7) Vacuum leaks
8) Incorrect or poorly calibrated PROM
Return to Chart
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CODE 45
Trouble Code 45 indicates that the O2 sensor is showing a persistently low exhaust oxygen content (rich), despite the efforts of the ECM to decrease injector on-time (thus decreasing fuel delivered). Integrator and BLM numbers may indicate < 128 by a substantial margin.
The conditions for setting this code are:
no Code 34 or Code 35 (MAF error) present, and
the O2 sensor voltage remains above 752 mV, and
the ECM is in Closed Loop control, and
throttle position is < 2 percent or > 20 percent, and
the above conditions exist for more than 20 seconds.
Typical causes for this code include:
1) O2 sensor defective or contaminated (if incorrect RTV sealant or too much RTV is used, this may happen)
2) Leaking fuel injectors
3) Fuel pressure too high
4) EMI interference from poor plug wires
5) Evaporative Emission system defect
6) TPS and/or EGR problem
7) MAF sensor reading higher airflow than is actually present
