boost problems on full throttle

[maundy26]

hi all, im new on the forum after buying a s3 8l 210 bhp . mods done are Badger5 V2 Turbo Intake Pipe, Relentless / XS power 3" downpipe with decat into a 2.5" powerflow stainless decat back system. Stage 1 custom Rtech remap, forge 008 DV and a few silicone forge hoses that replaced broken standard ones. its at 265bhp and 275 ft lb.

the problem is sometimes in 4th then most of the time in 5th and 6th. along the motorway i would be doing under 3k revs put my foot down halfway / all the way then the boost would shoot upto 20psi then drop off to 10 psi untill i hit just over 5k revs. then hold at 20 psi and boost nicely as a 265 bhp car should, so any ideas with this? i have changed the n75, its got a induacton kit so its all clean. im pulling my hair out thinking what it can be. any help would be great.

cheers

 

[maundy26]

anyone?

 

[darren t]

Have you scanned car with vcds ??

 

[maundy26]

no not yet, im from south wales so if anyone knows for one local that would be great, I have a obd reader so I may try that see what codes come up and report back here to see if anyone has had the same problem.

 

[darren t]

Could be anything too be honest mate really need car scanned for fault codes first then report back you will get your answers on here mate no problem people can't diagnose anything until you post up some scan results /logs!

 

[maundy26]

ok cool nice one. I shall get them later and report back, im expecting a list as long as my arm.

 

[darren t]

Same hear money/money/money that's all I've done since I've owned mine lol

 

[<tuffty/>]

Sounds like its going into a soft limp... as said, get hold of VCDS (there are links and info on how to do this cheaply in the stickies) get it scanned and post the results... there is also a link to Ross Tech's wiki explaining what the codes mean so you can do a bit of checking up yourself before posting questions..

<tuffty/>

 

[maundy26]

ok guys I have pluged in my mac tools one its come up as mass air flow sensor (g70) signal too low : p0102. so I will try and clean it up see if that helps but I don't think it will be this as it boosts fine after 5k but put foot down before 3 it spikes to 20psi then drops to 10 ish. between 3k and 5k it holds at 10psi then as soon as im over 5k it boosts great at 20. cheers for the replys too.

 

[maundy26]

funny what a good search on here does, this is my car http://www.audi-sport.net/vb/a3-s3-...tomer-d-few-niggles-though-advice-please.html

problems still there so im thinking change maf.

anyone agree?

 

[darren t]

funny what a good search on here does, this is my car http://www.audi-sport.net/vb/a3-s3-...tomer-d-few-niggles-though-advice-please.html

problems still there so im thinking change maf.

anyone agree?

yes mate Get one from tps I got one yesterday too cure my high maf signal I used tps this time and it is a genuine bosh maf I thought my gsf was genuine but turns out it wasn't!!only lasted 6months!!

 

[maundy26]

i shall give it a go and report back, hope it works

 

[maundy26]

Still the same lads, fitted a gen bosh one, its still doing it. Any ideas?

 

[russwuss]

Mine was going into soft-limb mode, running full boost for a second then causing the overboost fault code.. I replaced N75 (F version I think) and also a brand new OE DV and that's solved the problem.

http://www.audi-sport.net/vb/a3-s3-...st-pressure-control-upper-limit-exceeded.html

^ that's my thread

I also read a lot on here that the Forge DV isn't the best DV to have (unless you just want bling under your engine bay) OE seems to be the best rated on here.

Not sure if that will solve the issue here, but it worked for me..

 

[maundy26]

i have done the n75 valve for genuine parts. so im stumped may try and see if i can find someone local nd try swaping the dv and see if thats the problem. its doing my ed in lol

 

[Buzzer]

Might be a leak in a pipe, especially when its in the higher gears under the most strain. Get a smoke test done.