How to tell if it's the MAF or MAP?


happydog500
10-04-2010, 01:29 PM
I still have my problem in the higher RPM's as posted here http://www.automotiveforums.com/vbulletin/showthread.php?t=980404 I have a different question about the same problem. I went up the same mountain pass (6 months later). I got the same code.
Car runs with no code 6 months. I go up the long hill and get a code, but car runs the same. 6 months with out a code. When I go up the same hill, I get a code. Code goes away when I get back home.

I would think a MAP/MAF Sensor" would eather work or not. What makes it work but not up hills at 60mph?

Also, the code I had is for a "MAP or MAF Sensor. How do I tell which one it is?

For 6 months I had the original problem, I got no code. How come it doens't run right, but no code? When I get a code, nothing chages? Anyone know enough about sensors who can explane these things to me? Anything else I'm not mentioning you can tell me to help me understand?

Thank you,
Chris.

enslow
10-04-2010, 11:27 PM
A contaminated MAF can cause a lean condition and other drivability problems including shifting problems. A lean code can also be caused by a clogged EGR system, but I don't hear about this condition too much on Buicks.

You could try removing the MAF sensor and cleaning it. Some people recommend only using MAF sensor cleaner, others recommend using carb cleaner. In my experience, MAF sensor cleaner doesn't do a proper job of cleaning. I've confirmed this using voltage checks on a Ford type sensor. Carb cleaner did clean the sensor properly, with no damaging effects. A GM dealer service tech also recommended carb cleaner, so I was confident it would be ok.

Bottom line is, it's cheap and easy to clean the MAF sensor and will restore your milage and performance. It may even get rid of the codes. If you cannot find a procedure for cleaning the MAF sensor, I or some one else here might be able to post something.

happydog500
10-07-2010, 07:12 PM
I already cleaned it with MAF Cleaner. Didn't do anything. After 30 (or is it 40) starts without the problem the code goes away. I think I'm at or past that by now.

Might not be the MAF Sensor. Can I clean the MAP Sensor with MAF Cleaner?

Chris.

enslow
10-07-2010, 09:13 PM
You may wish to try carb cleaner on the MAF. Notice that I found MAF did nothing to clean my MAF, but carb cleaner did. On my Mercury, you test the MAF by measuring voltage. It is supposed to be 0.6V at idle. It was 0.8V and failing Aircare. MAF cleaner brought the voltage down to maybe 0.75V and I still failed AirCare. I tried carb cleaner and it brought the voltage down to 0.6V.

The MAF is tested differently on Buicks because it works on frequency rather than voltage. Frequency at idle should be near 2000Hz to 10000Hz at maximum engine load, or 4-7 g/s at idle to 100g/s at WOT.

I'm not saying that this is your problem, but don't assume that because you cleaned your MAF it is clean. It may, in fact, still be contaminated.

happydog500
10-11-2010, 03:48 PM
I will try Carb Cleaner on the MAF and post back. Do you know if I can spray Carb Cleaner in the MAP Sensor?

enslow
10-11-2010, 06:47 PM
I will try Carb Cleaner on the MAF and post back. Do you know if I can spray Carb Cleaner in the MAP Sensor?

I'm sure some one on here knows how or if the MAP sensor can be cleaned. I sure wouldn't touch it yet. Because the MAP sensor measures air pressure, it will work completely differently from the MAF sensor.

happydog500
10-19-2010, 02:45 PM
I asked around and most say never put carbcleaner on a MAF. That's why they make special MAF Cleaner, because you can wreck a MAF easily. From what I can see, it may work right away, but later it fails with carb cleaner.

I figure I could do it, but if anything goes wrong, I can't fix it because of no funds.

I took off my air cleaner box (another problem) and found some antifreeze. This is after my new UIM - LIM Job.

Can this be my problem?

http://i995.photobucket.com/albums/af78/happydog500/intake-1.jpg

I would hate to do this job again.

Chris.

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