MAF Problem possibly, advice needed

[sportquattro]

Apologies if this is going over old ground that's been asked before. I have a 1999 S3 210BHP with a Superchips remap, the car drives great but I have the feeling it should be better, and reading on the forum that in Vag-Com i should be seeing a g/s figure in excess of 200 I thought i would check things out. After several runs in 3rd and 4th gear the best reading i got was 171.94 @ 5880rpm. This would seem to be a low figure for a remappped engine. I have check for fault codes and there are none showing in VAG-Com, and I cant see anything obvious hanging off the car. I have unplugged the MAF but the seat of the pants test didnt reveal any appreciable change in how the car dove. Are there any suggestions as to what I should be looking for in other VAG-COM measuring blocks, or any suggestions as to what the problem might be? I was hoping the MAF unplug would have revealed the problem, but am loathed to change the MAF without good cause. If it helps, when the MAF was unplugged the car didn't like to idle, and is in standard form other than the remap and has 67000 miles FSH, & well looked after. In general the car drives well, and feels rapid, just not rapid enough. Any suggestions most welcome

 

[Y83OLK]

Try block 115 (on vagcom)
Required boost vs. actual boost.
171's low for a mapped s3, mine pulls 205+ all day long.

 

[sportquattro]

Try block 115 (on vagcom)
Required boost vs. actual boost.
171's low for a mapped s3, mine pulls 205+ all day long.

Thanks Callum, will try that tomorrow and post results

Nige

 

[leshkin]

171's low for a mapped s3, mine pulls 205+ all day long.

Well it is a Superchips map afterall

 

[sportquattro]

Went to log reqired boost Vrs actual boost today to find that the shareware copy of Vag-Com doesn't log block 115, or if it does I can't seem to make it do it, if anyone near Plymouth has a full VCDS and cable and is feeling kind, generous and helpful a few beers could be coming their way in return for them scanning my car. As an aside I have ordered a Forge 007p DV from Awesome GTI (£72.50 inc P&P) on the basis that the standard DV is a known issue on remapped engines. Hopefully a worthwhile change anyway, but also in the hope that if it is duff and leaking boost then it may just be the fix required.

Any other ideas welcome

Nige

 

[sportstractor]

im in barnstaple and have fully working vagcom, probably a bit far for you though. Possibly register your version?

 

[sportquattro]

im in barnstaple and have fully working vagcom, probably a bit far for you though. Possibly register your version?

Hi Sportstractor, thanks for the offer, I'll definately keep that in mind as an option if no-one closer has one and/or if the Forge 007p does not do the trick. I intend to buy a genuine VAG-COM cable and software in due course but have just had a walloping to the wallet from the tax-man so need to let the £££ recover first.

 

[sportstractor]

im having the same problem mate, im fairly sure its a boost leak, hopefully the DV is letting by. Not sure if it would make maf read low, but symtoms are a decline in MPG and down on power, also get a swooshing noise when accelerating. Im ordering the same DV tonight. If this does not work I will be looking for boost leak/ vaccuum leaks more thoroughly.

Is it confirmed that your maf will read low if you have a boost leak? as maf is preturbo this doesnt make sence.

 

[sportquattro]

im having the same problem mate, im fairly sure its a boost leak, hopefully the DV is letting by. Not sure if it would make maf read low, but symtoms are a decline in MPG and down on power, also get a swooshing noise when accelerating. Im ordering the same DV tonight. If this does not work I will be looking for boost leak/ vaccuum leaks more thoroughly.

Is it confirmed that your maf will read low if you have a boost leak? as maf is preturbo this doesnt make sence.

As its a closed loop system I'm thinking (yea hoping) that if the DV is not doing what it should the engine is not developing full boost, thus the overall airflow thorough the system is less hence the low reading, (That may of course be all ****** as I'm no expert) . The DV is a known weakness and for the sake of £70 odd its worthwhile upgrade anyway and could prove a simple fix. if not then it will be a full VAG-COM scan for boost leak and go from there.

Nige

 

[Mpathe]

im having the same problem at the moment aswel 99 apy s3 apr remapped and mine does about 155 maf and ive work it out to be running about 15 psi boost, also the load % is about 170 at 5500rpm. any help as to what to do now thanks mike

 

[sportquattro]

im having the same problem at the moment aswel 99 apy s3 apr remapped and mine does about 155 maf and ive work it out to be running about 15 psi boost, also the load % is about 170 at 5500rpm. any help as to what to do now thanks mike

From what I can gleen from here it's likely to be a boost leak, unfortunately my shareware VAG-COM doesent let me measure requested boost vrs actual boost, but as I'm still running the standard Audi diverter valve, I'm making the swap to a Forge 007p as a first step, I realise that this may not be the cause, but, it's a worthwhile upgrade anyway, and I'm an optimist.

if you have access to a full copy of VAG-COM try and log actual v requested boost. Also, have you tried disconnecting the MAF and see if it make any difference to how the car drives. Also check all your various hoses for potential boost leaks, a common issue with older S3's as the rubber perishes

There are a lot more savvy guys on this forum than me, so hopefully someone might have other better ideas.

Hope this helps
Nige

 

[sportquattro]

OK folks, latest on this problem. Fitted new Forge 007P and found the vaccum pipe to the DV had a small split so replaced that, along with the Cylinder head breather pipe which had also got a small split. Took car for a test drive and logged with VAG-COM - no difference whatsoever still showing 170g/s so, today had the car into a local fuel injection specialist to get him to log requested boost vrs actual boost, and he says everything seems normal in that respect, and he commented the car feels very quick. I have orderd a new MAF from Audi Plymouth which will be in on Friday, so were hoping it's just a tired MAF. Does anyone know if a MAF thats on the way out would produce thse problems? No fault codes, and unplugging it seemed to make no diffference. Will post again when new MAF fitted but any other suggestions welcome.

 

[Y83OLK]

Hi Nige.
I wish i knew your were going to change your DV earlier. As i have a spare here you could have had.
Ive even got a full Vagcom lol.
All (hotwire) Air mass meters will degrade after time, so hopefully this will cure your fault.

What fuel do you use? As when i run mine on 95 it runs like a nail, and i get knock from 3-6k.

 

[sportquattro]

Hi Nige.
I wish i knew your were going to change your DV earlier. As i have a spare here you could have had.
Ive even got a full Vagcom lol.
All (hotwire) Air mass meters will degrade after time, so hopefully this will cure your fault.

What fuel do you use? As when i run mine on 95 it runs like a nail, and i get knock from 3-6k.

Hi Callum,

Run on Shell Optimax whenever i can or Tesco 99 Ron Super unleaded if cant find a Shell station. I'll fit the new MAF Friday and see how it goes, if no joy I'll ping you back and nip over and return your Haldex Spanner and drop off the beers I have for you by way of thanks for the loan, and if poss get you to scan it with your full VAG-COM.

Cheers buddy
Nige

 

[Y83OLK]

No worries Nige, Ill be at home all next week... so no doubt ill be fettling with the car.

 

[Mpathe]

ijust thought i'd let you know how been getting on.
anyways so im having the same problem as above ie not running full boost so ive changed all my vaccum hoses, changed to a forge 007, changed the maf and still difference. so i was thinking n75 i think its called boost controller is faulty so i thought i would disconnect the pipe going to the actuator and just see what happens. when i relogged boost and maf i was getting
requested 2150 highest
actual 2450 highest
maf 207 highest

so do you lot think im right in thinking that its the n75 or not thanks mike

 

[sportquattro]

Well guys it's good news, fitted new MAF on the weekend and ran VAG-COM on it today and the beastie is now flowing a healthy 204g/s so a big thankyou to all those that offered help and advice.

Nige