Audi s4 Falling on its face going into boost

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rguil
MS/Extra Newbie
Posts: 7
Joined: Wed Nov 30, 2016 1:33 pm

Audi s4 Falling on its face going into boost

Post by rguil »

Been running a ms3 pro on my b5 audi s4 for about a month now and i love it so far compared to the stock ecu. I am lost for words on this one, i dont usually post asking for help but i have no clue what is happening on this issue and any advice would be appreicated.
Details about the car, forged internals, 2.8 heads, cams, bigger turbos, DBC throttle body conversion, fueling ect.

My issue is when i try to go into boost, the car completely stumbles flat on its face like the ecu is cutting spark and fuel. Even though i am at WOT, the car acts like it is going into overrun.
My turbos are set to just waistgate pressure (20psi) but i can barely coax it above 10psi by trying to be light on the throttle before the issue is prevalent.
Other than this issue the car is running great, just no boost. :evil:
Attached is a small log of the issue.
Any help would be greatly appreicated.
93supercoupe
Master MS/Extra'er
Posts: 581
Joined: Sat May 10, 2014 4:57 am
Location: New Haven, Ct, USA

Re: Audi s4 Falling on its face going into boost

Post by 93supercoupe »

Post up the tune too. Maybe its hitting boost cut
BootlegTuned
elaw
Super MS/Extra'er
Posts: 2926
Joined: Fri Oct 16, 2009 6:20 am
Location: Wilmington, MA

Re: Audi s4 Falling on its face going into boost

Post by elaw »

I was thinking the same thing, but according to the status flags neither fuel nor spark is being cut?

I'm wondering if the problem could be weak spark, due to wrong dwell settings or some electrical issue.
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking

Be alert! America needs more lerts.
93supercoupe
Master MS/Extra'er
Posts: 581
Joined: Sat May 10, 2014 4:57 am
Location: New Haven, Ct, USA

Re: Audi s4 Falling on its face going into boost

Post by 93supercoupe »

Yea it could be but the PW follows along with the lean spikes so it may be legit and the VE table needs help.

Hes at over 115% at only 150kpa. I guess that could be accurate, but idk.
BootlegTuned
Matt Cramer
Super MS/Extra'er
Posts: 17507
Joined: Thu Apr 16, 2009 8:08 pm

Re: Audi s4 Falling on its face going into boost

Post by Matt Cramer »

I'm thinking it may be running so rich it is misfiring and giving lean spikes.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
rguil
MS/Extra Newbie
Posts: 7
Joined: Wed Nov 30, 2016 1:33 pm

Re: Audi s4 Falling on its face going into boost

Post by rguil »

I have attached my msq, sorry for the delay. I am using VW/Audi r8 coils with a dwell rate of 1.8. Changing the dwell time does not effect my issue. New plugs gapped to .26 ngkbrk7e heat range 7.
Thank You.
rguil
MS/Extra Newbie
Posts: 7
Joined: Wed Nov 30, 2016 1:33 pm

Re: Audi s4 Falling on its face going into boost

Post by rguil »

Fixed as per the advice of others.
It was just running so rich under boost it was bogging down severely.
I used the auto fuel VE table generator and it was way off from what i needed.
Goes fast again! :yeah!: :yeah!:
Thank You everyone
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