Flat spots over 5,000rpm since RS2 turbo fitted?!

[DarrenM]

Right, sorted!! I got car plugged into VAG-COM and re-set the codes (inc the airbag code -airbag light has been on the last week from where i changed the 4 spoke wheel, light has now gone out).

From the quick blap home via a few bypasses, car is now pulling & boosting a treat all the way to the red TBH Im surprised this simple quick fix has sorted it tho so im keeping my fingers crossed!

Thanx for all the advice..

[Rusty]

How queer...

[DarrenM]

Now this is weird...havent driven the S2 for the last week, changed the Div valve back round to normal at the w/end tho fired her up and car was not only showing airbag light on but also got the same probs again with it stop start boost after 5,000rpm....it also boosts stupidly in 4th gear, heading toward the 2 BAR mark..

It maybe coincidence as obvoulsy just changed the Div valve round wouldnt do this.......BUT WHY and WHAT is making it do it?

Got the monkeys at local garage to plug in their VAG-COM equivilant, got rid of the air-bag light ok but still having the on off boost and flat-spots...

Getting well p*ssed with it now...any more ideas..??

[S2central.net]

Next time the monkeys clear some fault codes - have them tell you what they were - that might actually help in a somewhat scientific / organised / commen-sense approach to finding the root of this problem.

I know the s/w is good... Only edit for you was MAP scaling but its the same boost profile.

Get the garage to measure your fuel pressure... and also let us know the voltage at the pump terminals.

What wastegate spring is in there out of interest ?

I think the airbag light is a red herring (i/e unrelated) unless there is a general voltage or earth problem on the car - the airbag controllers are picky about that.

[S2central.net]

Just another thought - check that you haven't disturbed any loose wiring when fiddling withe the TBV/DV.

Is the WGFV fresh ?

If the WGFV is sticking it could cause grief.

[DarrenM]

Just another thought - check that you haven't disturbed any loose wiring when fiddling withe the TBV/DV.

Is the WGFV fresh ?

If the WGFV is sticking it could cause grief.

Yeah, its a brand new one when the turbo went on a few weeks back, thats what i had narrowed it down to. I had re-positioned one of the pipes leading into it slightly as it was looking tight (and i thought possibily starved) to the Samco that attches to bottom of DV. Thats the only area I've worked on over the w/end.

I will get a proper VAG-COM on it and see what that reveals. The only other local'ish garage I know that I trust hasnt got a proper VAG-COM but a Snap On version so poss limited in their findings. For obvious reasons not to keen on going to Audi dealership either..

[Rusty]

I know it's a little distance but All Audi have diagnostic equipment and are pretty savvy with S2s, give them a call and speak to Alex (Chen on here).

[andyg plym]

Standard ABY S2's at the mo. i know RS2 manifold,injectors,IC etc would get optimum from it but thats all to be collected and go on later in year. Why, do you think symtoms are current injectors maxing out??

what kind of power can you make with the standard aby setup + rs2 turbo and pauls chips? not touching anything else?

[Rusty]

I think it's reliant on the injectors so 320 or so? Not a huge amount more than the k24 can do amd more laggy but it's all about what it's capable of with the right mods...

[DarrenM]

It was going on a Maha r/road this friday to get an accurate figure but will have to cancel if cant sort before.

Just had a nice hour or so blast but boost & flat-spots still on/off top end...crap!

[S2central.net]

Andy is right - this setup is injector limited... its really only a stopgap to full RS2 setup.

Been looking at chips again (especially after a new temperature related finding to improve Andy's setup further) and something *might* have been lost in translation on the turbo map from original 3bar application to your 2.5bar one. I can't be certain right now, and its odd that the car ran fine for a while with this setup. We need to determine why it was bad, then good, then bad again - with same software.

To completely remove any doubt on the turbo chip... If you can source a 3bar MAP/VMAP I will fit it for free and swap in the one that I have absolute faith in... Please post back the other chips as well cos I'm running a bit low on extras here.

Nothin like a bit of debug in public ehehh ?

Paul

[Rusty]

This is a strange one. IME if the car doesn't cut out then it's usually a small boost leak causing the problems but no idea why it would be up top. SOunds WG related to me, if thde WG can't open far enough then you'll run into trouble, the same goes for the reverse.

[DarrenM]

Yep, new plugs from service at MRC not that many miles ago and recently checked all are were tight.

When it went on vag-com (well, snap on equvilant) when started having these probs didnt bring up any codes for fuel pump.

Keep the ideas coming tho coz will put it to them when i pop in later this week.

[S2central.net]

There are no codes for fuel pump !

The only fuel related codes that you can get are in part-load / adapted conditions if the ECU cannot adapt to a fuel related problem. But at WOT it ignores all the adaptation stuff and runs off the map... If your fuel system isn't delivering the right amount (and its critical here) then you get grief.

Two workaround possibilities before a 3bar VMAP gets to you...

1 - Run on K24 software which won't be stressing your fuel system
2 - Fit a variable FPR and increase pressure until the misfire goes away (and hope to stay within adaption limit)

[DarrenM]

Hmmm, these options are starting to get a bit more expensive than i thought, i was under impression RS Turbo and map "should" be fine, obviously not getting the most, but still a good reliable 300+ bhp.

At another few hundred for a 3BAR Vmap i think i'll try a variable FPR if anyone got any reccomendations??