Symptoms of a dodgy MAF?

[Y83OLK]

Hi all.
Whats all the symptoms of a dodgy maf?.

Last time i VAG-com'd it, my maf was reading a little bit low (compared to "sportquatro's")
Peaked at 190g/s.....Stage 1 map.
Now, my fuel consumptions down to < 20mpg.

And at 5.5k rpm, its like hitting a brick wall.... Fuel cut?. (like when the esp comes in)

Ive got the new MAF here infront of me (impulse buy)
Just wondering if all of the above are common symptoms.

Cheers

 

[finesse]

Did you buy a genuine Bosch MAF?

Dodgy MAF - Rough Running At Idle, Cold Start Problems, MPG, Running Rich/Lean

Have a look; Diagnosing a bad MAF

 

[Y83OLK]

Cheers finesse... Pics been saved for future reference.lol
I think ill need to get a new battery in the laptop, and see what 006 is reading.

 

[sportquattro]

Hi Callum, Have you tried running it with the MAF unplugged? It wont Idle very well but, if it revs and performs as it should then you know it a MAF issue. Economy should be a lot better than <20mpg. If you want to do some back to back comparisons with mine on VAG-COM just shout and I'l pop over.

Nige

 

[sportstractor]

And at 5.5k rpm, its like hitting a brick wall.... Fuel cut?. (like when the esp comes in)
Cheers

could be loads of things, but sounds ignition related to me. Spark plugs coilpacks been changed recently? Some times if plugs are lacking power etc the spark can be 'blown out' at certain rpm and it feels alot like an engine limiter.

 

[Y83OLK]

Well, i braved the weather and stuck my new MAF on thismorning.
Just been out for a hoon.. And it goes like stink now.
Boost comes in just below 3k (before it was 3.5) boost runs out around 5k.. But still pulls well till 6.

Happy with that, just need to check the fuel consumption now lol.

 

[OllieH]

Interesting I might have to change my MAF. I can hear my turbo boosting up from 2.5k rpm but don't get the kick until 3,200 rpm+. I can't find any leaks and the plugs and coilpacks are all new. How much was your MAF?

P.s. Glad you got it sorted :icon_thumright:

 

[Y83OLK]

Hi mate.
I got it trade for £61.
But theres a £20 surcharge on the old unit.

RRP is £79.90 +£20 + Vat Through TPS

 

[finesse]

Interesting I might have to change my MAF. I can hear my turbo boosting up from 2.5k rpm but don't get the kick until 3,200 rpm+. I can't find any leaks and the plugs and coilpacks are all new. How much was your MAF?

P.s. Glad you got it sorted :icon_thumright:

Most/some people kick in from 2500RPM

 

[finesse]

Hi mate.
I got it trade for £61.
But theres a £20 surcharge on the old unit.

RRP is £79.90 +£20 + Vat Through TPS

Bosch?

 

[Y83OLK]

OE.. should imagine its bosch.
Partnumber 06A 906 461 MX (For a 2001 S3 AMK)

 

[OllieH]

Most/some people kick in from 2500RPM

Mine used to until I had a coilpack go a couple of months ago, and ever since the kick doesn't come in until 3,200+. Have since changed all coilpacks and plugs, have looked for boost leaks, so next thing will be MAF I think.

Sorry for stealing the thread :icon_thumright:

 

[finesse]

Mine used to until I had a coilpack go a couple of months ago, and ever since the kick doesn't come in until 3,200+. Have since changed all coilpacks and plugs, have looked for boost leaks, so next thing will be MAF I think.

Sorry for stealing the thread :icon_thumright:

MAF is relatively expensive so take vagcom logs to gauge the general health before replacing, if you do, make sure you get a genuine Bosch MAF; 06A 906 461 M


http://autotechrepair.suite101.com/article.cfm/mass_air_flow_sensors

and

http://wiki.ross-tech.com/wiki/index.php/Fuel_Trim_Info

Here's a good sanity check for the status of your MAF. Do a full-throttle run all the way to redline in a single gear (second works fine). Group 002 usually shows air mass in g/s (in many modern ECU's, consult your Factory Repair Manual for the specific group for your particular vehicle). Your peak airflow should be roughly 0.80 times your horsepower if you are close to sea level. So, if you have a stock 150 hp 1.8T, expect around 120 g/s. If you see significantly less than that, you MAF may be on the way out. Also note that airflow will be markedly different at higher altitudes due to reduced ambient air pressure, especially with naturally aspirated engines that do not have forced induction to overcome that deficiency. This still works if you are chipped, but "race" programs may make more power through timing, rather than airflow. Therefore, take all readings with a grain of salt.

Good Luck!

 

[StrmsekS3]

Hello, looking to pick someones brains, my 2002 S3 has twice now when started run rough (idles much higher than normal and is not steady idle) this has only happend twice once from cold start and other car had driven 2 hrs stopped for 4 hrs then started again and it happend, i dont use the s3 often but wondering if it may be the MAF?? dont have access to vagcom.

anyone had the same or know what it may be?

cheers

 

[sportstractor]

same thing was happening to me, started playing up after a smoke test i had done on it. Would only happen sometimes when starting from cold and would be erratic. When I changed the maf it all went away

 

[BuuBBa]

Could MAF be end of its life time even though the readings seems fine? Car has rough idle sometimes and is running rich. I unplugged the MAF and the engine coughed two seconds and then came back "normal". Couldnt find any boost leaks and the PCV check valve is new.