99 z34 code question
#2
P0102 - Mass or Volume Air Flow Circuit Low Input
Symptoms
- Engine stall
- Engine running rough
- Excessive fuel consumption
- Excessive smoke
- Engine Light ON (or Service Engine Soon Warning Light)
Possible causes
- Dirty mass air flow sensor
- Dirty mass air filter
- Mass air flow sensor harness is open or shorted
- Mass air flow sensor electrical circuit poor connection
- Intake air leaks
- Faulty mass air flow sensor
Tech notes
Before replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with low compress air or mass air flow sensor cleaner. Reset code and drive vehicle. If the code comes back, it may be necessary to replaced the mass air flow sensor.
P0171 - System Too Lean Bank 1
Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Excessive Fuel Consumption
Possible causes
- Intake air leaks
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Faulty Mass Air Flow (MAF) sensor
- Incorrect Positive Crankcase Ventilation (PCV) hose connection
Tech notes
Dirty air filter of faulty air flow sensor are common causes for the P0171 code of the problem.
Symptoms
- Engine stall
- Engine running rough
- Excessive fuel consumption
- Excessive smoke
- Engine Light ON (or Service Engine Soon Warning Light)
Possible causes
- Dirty mass air flow sensor
- Dirty mass air filter
- Mass air flow sensor harness is open or shorted
- Mass air flow sensor electrical circuit poor connection
- Intake air leaks
- Faulty mass air flow sensor
Tech notes
Before replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with low compress air or mass air flow sensor cleaner. Reset code and drive vehicle. If the code comes back, it may be necessary to replaced the mass air flow sensor.
P0171 - System Too Lean Bank 1
Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Excessive Fuel Consumption
Possible causes
- Intake air leaks
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Faulty Mass Air Flow (MAF) sensor
- Incorrect Positive Crankcase Ventilation (PCV) hose connection
Tech notes
Dirty air filter of faulty air flow sensor are common causes for the P0171 code of the problem.
#5
Also try just unplugging the MAF sensor...and see if it runs any better or different....
I noticed you didnt post how its running or performing....
(I have the same vehicle)
Last edited by STUMPMI; 03-21-2012 at 09:38 AM. Reason: typo
#8
A quick check to see if it is the MF......unplug it and then start it up and see if it idles and stays running.....
If it fixes the shuttering and stahling......then you know the MAF is bad... If it is.....try cleaning it with MAF cleaner.....I ended up replaceing mine......as it was bad after 130,000 miles......
If that wasnt the cure...I would check your fuel pressure at the fuel rail...
Could be its time for a new fuel pump....
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Tadcaster
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01-07-2014 10:34 AM