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I have VCDS lite, but not the paid for version, so I dont think can read out those values as you suggested ?
On the other hand, I do have OBDII reader, and I just went for a short drive, and measured the MAF values with that. This is what I found :
At idle, with AC off, 4g/s.
At 2200 RPM, standtstill, approx 13g/s.
At full acceleration, value did got to approx 120g/s.
Isnt these values a bit low ? On my 165 HP engine, shouldnt I have a value of more liek 200g/s at full acceleration ?
Thank you for all advices.
Vegard
The guide claims the peak output of the sensor in g/s should "Roughly" be 80% of the rated engine horsepower "At Sea Level" so in your case the highest value of 132g/s vs. the 120g/s you have is 12g/s under and possibly a significant value of concern at 9.5%, but as noted before and mentioned in the guide that this difference could be the result of a vacuum leak, the other bit worth mentioning is the real time values on OBDII readers instead of using VAG diagnostic tools if it even applies here.
I'm hoping someone jumps in with more knowledge as I'm also interested in what else should be mentioned.
Last edited by jcman; 02-19-2016 at 04:27 PM.
Reason: WOT in second gear?
Just to jump in quickly with a question. What if the readings on VCDS are higher then it should be? Guess I have also a MAF sensor problem and I was following your instructions how to test it today. I have the same engine, 2.4L 165HP and I get a lil bit over 170g/s when in second gear and I was testing it 300 meters from the sea, so the level is maybe 2 or 3 meters above sea level. Is it time for me to replace the MAF sensor?
I also have a fault code on the MAF sensor but the best would be if I add a picture to this text. would be very thankful for any kind of help
Just to jump in quickly with a question. What if the readings on VCDS are higher then it should be? Guess I have also a MAF sensor problem and I was following your instructions how to test it today. I have the same engine, 2.4L 165HP and I get a lil bit over 170g/s when in second gear and I was testing it 300 meters from the sea, so the level is maybe 2 or 3 meters above sea level. Is it time for me to replace the MAF sensor?
I also have a fault code on the MAF sensor but the best would be if I add a picture to this text. would be very thankful for any kind of help
Out of the four codes you have it would be clear that the 16846 G70 fault is causing the others, I'd check the connection to the MAF also its possible the MAF is dirty "tricky to clean" or on the way out if its the original part.
Thank you very much for the reply Jcman. I have also been watching the Ross-tech video about fuel trim and how it actually works and the way I have understood it, a vacuum leak could be causing a error in the fuel trim. Is that right? Is the vacuum being generated just in the air hoses or also in the whole engine? The thing is that I know for sure that I have a oil leak from the Cam Chain Tensioner gasket and the way I have seen it today, looks also like I have a leak around the valve cover gasket. could this everything be causing the errors in the fuel trim. Soon I am gonna order those gaskets and replace them but it is very hard to find them in a complete set and even harder to replace them. Hope that this makes sense to somebody. Greetings from Norway
Thank you very much for the reply Jcman. I have also been watching the Ross-tech video about fuel trim and how it actually works and the way I have understood it, a vacuum leak could be causing a error in the fuel trim. Is that right? Is the vacuum being generated just in the air hoses or also in the whole engine? The thing is that I know for sure that I have a oil leak from the Cam Chain Tensioner gasket and the way I have seen it today, looks also like I have a leak around the valve cover gasket. could this everything be causing the errors in the fuel trim. Soon I am gonna order those gaskets and replace them but it is very hard to find them in a complete set and even harder to replace them. Hope that this makes sense to somebody. Greetings from Norway
Yes a vacuum leak will cause fuel trim problems however the crankcase vent system is somewhat separate from the intake manifold vacuum system by a Crankcase Pressure Valve, so if the CPV is bad it can cause a bit of an over-pressure condition "In the Crankcase" leading to gasket leaks in the VC and cam seal but keep in mind they will leak with age and I doubt this is your problem mainly because the MAF code you have don't suggest this.
Now that we understand what the MAF sensor is doing and no vacuum leaks exist so all indicators are pointing to a failing part or bad connection.
interesting that you mention that because I know for sure that the previous owner has changed the valve cover gaskets two days before I bought the car. Some other guy was coming to look at the car before me and then they have noticed the burned oil smell in the car and the owner did not want to sell it before he finds out what the problem is and fix it. car had a service book from the first day and all until I bought it. so, is it then a bad sign that the valve cover gasket has started to leak after maybe 6 months? and it has been done in a Audi service shop. I was also looking thru the service book and I can not find any note that the MAF sensor has been replaced and the car has 169000 miles behind him
02-16-2016, 01:46 PM
Normal MAF values ?
