air mass sensor

[marco_jr_86]

my 98 jetta is running real rough, and is eatting alot of gas and sounds real bad. i brought it to a mechanic and he said the air mass sensor needed to be replaced. my dad then brought it home took the sensor off and the hose that is connected to it had oil in it. if anyone could help me i would appricate it. thank you

marco

[boschmann]

Which engine?

[marco_jr_86]

it is a 2.0

[boschmann]

It might have been contaminated by the oil. Check the plastic valve at the top of the valve cover, the rubber hose coming from it & the plastic pipe going into the engine block, all are prone to fail & can cause oil build up as stated. A mass air flow can totally fail, setting the light w/a MAF code or more usually get out of calibration & eventually set air/fuel ratio codes. Checking the mass air flow for being out of calibratiion requires a scanner capable of reading datastream & the knowledge to know what you're looking for. Your symptoms seem like a possible temp sensor issue, did your mechanic investigate this possibility?

[marco_jr_86]

thank you for the reply. i brought my car to auto zone and the computer said there was two things wrong with it:

# crossed: P0172 which states that "the fuel system for bank one was too rich."

# crossed: P1127 which states "exhaust not warm."

if you help me i would really appreciate it.

[boschmann]

It does sound like the MAF, to fully diagnose you would have to be able to read certain measuring blocks using a VAG-COM scanner or equivalent. They're widely available and fairly inexpensive now, so it may be easier to just replace it. One other posibility is the coolant temp sensor is bad, causing the engine to run rich. It is located in the cooling hose flange at the back of the cylinder head. It has a blue & brown/blue wire. Unplug & test with a Ohmmeter. Resistance on the sensor pins should be 2000-3000 Ohms w/engine cold & go down to 200-300 Ohms at operating temperature.

[edspecR]

you can also try cleaning the maf by putting it in a ziploc bag and pouring in some rubbing alcohol. getting a new maf is best, but if its just a dirty maf (from the oil) cleaning will help. also check your exahust o2 sensor

[boschmann]

I've heard alot about that working, although it hasn't on any I've ever tried it on. Just make sure you dont use checp alcohol. Use at least 90%, available at most pharmacies.

[Noble61304]

there is a breather that goes into the engine block that helps regulate the air into the Engine, if that is bad an clocged it will send oil back into the Mass Ait tub and clog the shit out of it, check that.... i had that same problem an that was what it was

[marco_jr_86]

the car is running better now after i have cleaned the mass air flow censor. but now i have ran into another problem; when i stop while the air conditioner is on the car stalls. when i start the car up again and leave it running without moving and put the AC on the rpm's go up and down and sometime it stalls. please if you could really help me i would appriciate it.