If there are oiled K&N filters on the car, the MAFs can get ruined very fast.
Also with the stock paper intake air filters, a tiny hole or leak past the seal will cause MAF trouble.
If there is oil present in the plenum chamber (the part on top of the engine where it says "M Power"), that can destroy the MAFs fast too. Take the lid off the plenum chamber and look. (Most often oil in the plenum chamber is from one of the oil separators, either directly or indirectly when a voanos is leaking oil into its drain, and this drain overflows and pushes oil back up into the oil separator drain)
Further, the symptoms described can also be a vacuum leak somewhere in the engine vacuum tubing.
Have a look at the first post in this thread. I´ve updated it with info how to test the MAF separately using a voltmeter. Use that procedure any you will know for certain if one or both MAFs are contaminated.
No K&N oiled filters. I read your comments about these before
I went to the dealer today to pick up my BMW Sauber Formula 1 child seat (just got a daughter last week ), and had them attach the car to the computer. Cam position sensor failure, and an error on cylinder 4. Cam position sensor is ordered, and will be installed on Tuesday. They said to wait and see what happens with the cylinder problem...
Finally got around to doing the fuel flow test. At WOT, in 1st and 2nd gear, the BEST fuel flow numbers I got with your NEW MAFs are as follows. This was after about 35 different tests:
104 L/h
170 L/100km
I am at 7000 feet altitude. Temperature was 72 degrees fahrenheit. Humidity 14%. Barometric Pressure 30.17"Hg (F) (1021.67 millibars)
I'm still getting the SES light ever since I installed the MAFs..
I just realized something. Doing this test requires you to hit the rev limiter. Every time you hit the rev limiter, the fault gets stored in history. What happens if the engine blew up on an unrelated incident and the dealer claims it's not covered under warranty because of driver abuse due to the fault codes? I am reminded of previous stories like this, such as templeM5's blown engine.
Hitting the rev limiter causes a fault? Never heard of that. I *have* heard of improper downshifts causing overspeeds that are recorded, but not simply hitting the limiter. Do you have any documentation of this behavior?
Hitting the rev limiter causes a fault? Never heard of that. I *have* heard of improper downshifts causing overspeeds that are recorded, but not simply hitting the limiter. Do you have any documentation of this behavior?
Nope. I wouldn't mind being wrong on this one, but I'm not sure if the ecu can differentiate hitting the limiter on downshifts vs an upshift; I would think both actions cause an increase in revs and thus gets recorded.
I picked my car up yesterday, with the new cam position sensorS. It turned out to be 2 failing sensors. I have the impression that the tech at the dealer really knows what he's doing. When I brought the car in a few days ago for inspection, I told him I thought my MAFs were bad, and I said I knew they couldn't see that just by downloading data from the ECU.
His reply was: "That's true, we can only see it when they're completely dead. But we can see if something is wrong, by looking at the fuel consumption."
Ok, looks like he knows more than the average tech...
Anyway, got the car back, and it runs perfect. Big smile all the way home. I even went out for a late night drive, just because the car was driving so smooth (yeah yeah, still late night drives after owning the car for more than a year )
I picked my car up yesterday, with the new cam position sensorS. It turned out to be 2 failing sensors. I have the impression that the tech at the dealer really knows what he's doing. When I brought the car in a few days ago for inspection, I told him I thought my MAFs were bad, and I said I knew they couldn't see that just by downloading data from the ECU.
His reply was: "That's true, we can only see it when they're completely dead. But we can see if something is wrong, by looking at the fuel consumption."
Ok, looks like he knows more than the average tech...
Anyway, got the car back, and it runs perfect. Big smile all the way home. I even went out for a late night drive, just because the car was driving so smooth (yeah yeah, still late night drives after owning the car for more than a year )
Glad to hear you got your Beast running as normal and your experience with the techs was good, seems somewhat of the exception than the rule these days. BTW, were the two failed CPSs the intake or exhaust ones (I'd think the intake)?
2Likes
), and had them attach the car to the computer. Cam position sensor failure, and an error on cylinder 4. Cam position sensor is ordered, and will be installed on Tuesday. They said to wait and see what happens with the cylinder problem...
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