Check Engine/Clean MAF/Clear Codes

A couple of questions, I have a check engine light on. Codes P0171 & P0174.

This guy said that he was able to clean the two wires on the MAF, and all was well...

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Is this something that can really work?

Secondly, he got the OBD-II codes, and I suspect used the reader to clear those codes? Is there any risk of the do-it-yourselfer in clearing those codes? I suspect if I did that on my car, the check engine light would quickly come back on with the same problem if I didn't correct that problem.

There are a few fairly cheep OBD-II readers on Ebay, any risk in getting a cheep one?

thanks,

Reply to
Mbt6
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Search this group and you'll find plenty of evidence it does work.

It, sometimes, also clears up driveability problems that havent yet set the CEL.

Why it's so... The MAF sensor circuit works by passing a current through those thermistors... the current passed will change as air passes over them, so the amount of current indicates the volume / temperature of the air.

If there's a film or dirt on those thermistors, that will act like a 'jacket' and the computer will think there's less air inducted than there actually is, thus injects less fuel

Since the MAF input sets the baseline on the air/fuel map, when the O2 sensor indicates it never sees a rich condition, the codes are set.

And here's a simple test to see if your MAP might be causing driveability problems:

Warm the car up, turn off the engine and disconnect the MAF harness.

If it starts and drives better, you have a dirty or bad MAF. If it gets worse, there's a problem with another sensor.

Finally...there are two misconceptions about cleaning the MAF

  1. The sensors are extremely fragile

- Wrong, A crystal wine goblet is extremely fragile. Comparatively, the sensors are like a mason jar

Just dont bang against them or drop any of them

  1. Electronic parts or contact cleaner aerosols are needed

- A soft toothbrush or unused paintbrush plus rubbing alcohol, dip, brush gently, rinse, repeat several times and you're in great shape.

Of course, there's risk... research the tool on the mfr site and using google and google groups

If you dont plan to spend a lot of time under your hood, it might not pay

See:

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Reply to
Backyard Mechanic

A vacuum leak will act the same way. Bob

Reply to
Bob

Thanks for the tip. I'll try this on thursday this week. I don't know if diconnecting the MAF will make the engine start or run better, it starts and runs great now.

Reply to
Mbt6

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