air flow meter replaced.. do i need to reset ecu

jpresto · 29-08-2009,01:18 PM

after recently replacing a faulty air flow meter (diagnosed by main audi dealer) my car is now driving like when the problem first occurred, do i need to reset the ecu before my drives properly again?

**toff** · 29-08-2009,01:35 PM

I'm no expert but I believe If you have no engine management warning light showing, then NO - the car should just start working with the readings from the new MAF straight away.

If you do have an engine management warning light showing then error codes will need to be cleared first. In your case, there seems to be something else wrong.

There could be quite a few things causing rough running / flat-spots (I assume you are experiencing something like that?) Possible causes are faulty EGR pump, split air hoses, sticky N75 valve etc.

Please describe the problem with your car and let us know what you're driving, 1.8T / 1.9 TDI etc?

Cheers
Al.

jpresto · 29-08-2009,03:24 PM

my car is a 1.8t quattro, i had no warning lights for the bad maf, i recently had the code p0411, i had two vacuum hoses replaced and the code was reset, my turbo boost is very limited, the car hesitates on fast acelleration, also i cant hear the turbo whistling, its causes havoc with the steering aswell, keeps going heavy.. any ideas..?? thanx

**dufferum** · 31-08-2009,01:03 PM

sounds like leaking air intake pipes, check for smears of oil around joints

jpresto · 31-08-2009,03:42 PM

ive jus noticed the 2 way pipe that connects to the cylinder head is melted, think it leads down to the oil fliter one way and the diverter valve the other way, would that effect perfomance? i think the car keeps going into limp mode..

**dufferum** · 31-08-2009,05:34 PM

its all part of the vacuum system, if you loose pressure in any pipes its bound to affect performance, i have had similar issues, its always worth replacing them first to eliminate them.

**toff** · 01-09-2009,12:27 PM

If unmeasured air is getting in to the system behind the MAF, the ECU will think the engine is getting less air than it actually is, so the fuel / air mixture will be wrong and the car will run rough.

The Lambda probe(s) will detect that the stoich / fuel mix is wrong by sniffing the exhaust gasses and will flag-up the engine management light / possibly send the car into limp mode.

I believe all modern engines have knock sensors (to prevent pinking). Your ECU may be retarding the ignition timing becuase too little fuel mixed with too much air leads to detonation (pinking) and that would definately flag-up the engine management light.

Let us know how you go once those pipes have been replaced.

Al.

**wmccann** · 02-09-2009,02:52 PM

When you replace your MAF you need to unplug the battery for approx 30 mins. When you plug back in, the system will have lost all previous settings and will use the standard settings.

After a period of driving the system starts to adjust itself to correctly match the readings from the new MAF.

BTW if you have a vacuum leak then the above won't help. on my A4 V6 one of the pipes was incredibly brittle (under the engine cover) and shattered in my hands due to being made of plastic and being in constant contact with the engine - how stupid can Audi be???

Walter.

jpresto · 17-09-2009,07:24 PM

the melted hose turned out to be the oil breather hose, it had tottaly kinked as was full of black gunk, after replacing it the car ran perfectly for about 3 days then starting losing power, when i turn the car off and on it drives better, but not perfect. I also replaced the pressure regulator valve (dump valve) because that was also gunked up, still not running right, i also replaced all 4 spark plugs.. i noticed oil round the 4 plugs opposite spark plugs.. im not sure what they are.. pls help!!

**TullyAGS** · 18-09-2009,09:35 AM

[QUOTE=i also replaced all 4 spark plugs.. i noticed oil round the 4 plugs opposite spark plugs.. im not sure what they are.. pls help!![/QUOTE]

Do you mean the coil packs (you pull them out from on top of the spark plugs)? was there any oil on the spark plugs or in the wells. If so your cam cover gasket has failed, not too difficult to replace. Also have you checked that the coil packs are working properly, not getting any misfires or anything?