When to replace MAFs?

4.2 V8 40v biturbo - 450 bhp
4.2 V8 40v biturbo - 480 bhp (plus)
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Shoppinit
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Post by Shoppinit » Mon Feb 08, 2010 8:16 pm

Very easy. Have a look at the spark plug sticky.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

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Shoppinit
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Post by Shoppinit » Mon Feb 08, 2010 8:40 pm

You could also get some ignition inhibitor from Audi and spray it aroudn the engine bay to see if any unmetered air is being sucked in and where.

Engine leak detector spray part number G 001 800 A1
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

paul_23
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Post by paul_23 » Tue Feb 09, 2010 8:23 am

I dropped it back at Audi dealer today for front brake pads and I asked them to check the vac system considering they changed the vac hoses when the airbox was off while they did the MAFs. Will keep you posted.

paul_23
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Post by paul_23 » Tue Feb 09, 2010 9:30 am

Trying to rule out possibilities for it being lean - if the intercoolers are leaking then could they let unmetered air into the system ???? When on boost the air should be escaping but when cruising maybe they can suck in air???

I don't think this is the cause as I had a look at mine a few months back and there was no obvious signs of oil residue on them and we dont have salty roads to corrode them. Also, there was no fault code before the MAfs and the vac hoses were changed...

paul_23
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Post by paul_23 » Wed Feb 10, 2010 8:14 pm

Got my car back from the dealer and he said he has ordered MAF O ring seals as he thinks they are not air tight. The bottom seals were replaced last week so I said that if the top ones are leaking how can unmetered air be getting in as the air would pass thru the MAF. Anyway, they are on order so will take it back in next week to get it sorted.

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Shoppinit
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Post by Shoppinit » Wed Feb 10, 2010 11:13 pm

Are you having fun yet? :? I bet you'll be glad when it's all sorted.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

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