my S4...1st impressions!

[fletchie55]

I took the car for a quick run with the diagnostic software running. recorded groups 3 and 5.

My g/s mass air flow never got higher than 176, is this bad or to be expected? Ive been trying to attach the full spread sheet so someone might be able to give some advice but it doesnt seem to want to accept it.

[maxxximus]

Nah thats not good- stock motor should be reading a peak air flow around 212g/s.

Need to get it looked at.

[oliew]

try unplugging the maf plug, its the black thing that comes from the airfilter housing.
see how it goes then?
Ol

[fletchie55]

176 was the maximum achieved on only 2 of the runs, the rest got 171, 173!! would this be adversely effecting the performance of the car?
well I guess the good thing is that I might have discovered a problem, the bad thing is its even more expense!
there were no fault codes after the runs

[oliew]

hi,
when i first got my car i had the same problems, split hoses, both DVs were knakered, and a TBB split, also a knakered MAF i recon mine was the same , and if you look back on my posts about september 2005, mine sounded just like yours. lack of power, couldnt understand why the car wasnt as fast as i expected, a trip to MRC sorted all this in about an hour!
HTH
Ol

[fletchie55]

cheers oli!
so what was the total cost to sort that long list out? am I correct in thinking that the 710s are better than the standard DVs and therefore dont fail so frequently? ive seen these for about £17 each I think.

how much is a TBB and what is it?!
and a MAF? doesnt sound like a cheap part

finally, is it possible to fit them yourself?

[JonnyX]

I took the car for a quick run with the diagnostic software running. recorded groups 3 and 5.

My g/s mass air flow never got higher than 176, is this bad or to be expected? Ive been trying to attach the full spread sheet so someone might be able to give some advice but it doesnt seem to want to accept it.

Any error codes?

That looks like a very bad MAF to me. Explains your high MPG as well.
I wouldn't boot it if I were you, you are probably running very lean on
WOT.

[oliew]

hiya,
it cost me 2 DV's like you say about £20 each these 710s are stronger, not too hard to fit, 2 clips on each and a vacuum hose.
TBB = throttle body boot, where the 2 pipes come into the engine at the front its under the BITURBO cover this splits on the join mostly, bit harder to fit.

http://www.audiworld.com/tech/eng19.shtml

MAF are about 80/100 quid or something all these can be fitted yourself but i would definetly get down to MRC and let them check for boost leaks, you cant really do this yourself unless you get a compressor + other bits, you wouldnt believe the amount of hoses that can leak on these cars
the reason i say unplug the maf is that the ecu will use its own pre-set tables for setting the fuelling and yo ushould be able to tell if the maf is knakered, mine was more than 1 problem so it took a while to sort out!.
parts i would say budget £200 and then fitting costs, depends how many other problems there are
Ol

[fletchie55]

If I unplug the MAF and this is the problem (or the main problem) what difference will I notice?
I think il order some new DVs anyway seeing as theyre cheap and even if theyre not bad now theyre bound to die eventually.

what do you mean my high MPG? I thought my MPG was pathetic!! the average doesnt go above 25 even if im driving like a saint 72mph motorway etc

thanks for the help guys

[oliew]

if you unplug the maf the ecu will not use the air flow readings to adjust the fuelling it will use its own preset fuelling so the car should run nearly as normal!
my mpg is not too bad, i average 21/22 and about 28 on motorway i recon thats ok for a twin turbo v6
hope that helps
Ol

[davs4]

When my MAF was dying (it turned out to be the clip into it was broken and not making full contact)this gave me hardly any revs,whereas when unclipped it was free revving.Not advised for prolonged use though!!

[fletchie55]

where exactly is this clip I need to undo then? I have found what I think might be it! drivers side, attached to a part of an air pipe that says air sensor or similar, is this the one? Dont realy want to unplug the wrong thing!

[MCB]

The plug is here

[fletchie55]

excellent, thanks for that. It was the plug I thought, but thought I better check just incase!

There are no error codes at all on the car either before my run or after.
going to go out for another slightly more gently run and see if removing the plug makes any difference.... watch this space!

[maxxximus]

A few peeps on Audiworld run in 'Speed density mode' without ill effects. Emmissions/economy may be out the window but maybe safe to do so.

Dont know if id recommend it but in short term im sure youll be OK.