1.8 BT problems.

[Audi body]

So I have two main issues. A little about the car. 1.8 stroked to a 2.0, fully built head and block. Hpx blow through maf, gtx 3076r, schrick cams, 70mm throttle body.
The first is the car stalls every time I come to a stop. So far I've cleaned the maf, replaced throttle body and crank shaft position sensor. Also no codes.
The second issue. Vvds is giving me no idle or part throttle feed back in channel 32. It stays 0. I replaced the o2 with a real oem sensor and get the same. Still no codes.

[B5carl]

Idk if this would be much help but I worked on a Subaru once and had the same issue but it wouldn't completely stall. The throttle body Venturi was really dirty so when the valve would shut to the no throttle position it would almost completely shut due to the amount of dirt and grime.

I know you said that you replaced it but wouldn't hurt to clean it if you haven't already.

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[Audi body]

Thanks for the reply but the new one is fully cleaned and the old one wasn't very dirty.

[EuroxS4]

What tune are you using with that setup?? Id be more curious how the tune is setup for the hardware your using. I would try a throttle body adaption and look at mvb 32 this will tell you fuel trim readings. Note every time you clear the faults it will reset STFT AND LTFT back to 0. The norm is always between -5 and +5% it should never be outside of that. Also list any other modifications that were done. Are you running a catch can?? whats the pcv system look like and so on. When the car stalls does the EPC light come on??

[Audi body]

What tune are you using with that setup?? Id be more curious how the tune is setup for the hardware your using. I would try a throttle body adaption and look at mvb 32 this will tell you fuel trim readings. Note every time you clear the faults it will reset STFT AND LTFT back to 0. The norm is always between -5 and +5% it should never be outside of that. Also list any other modifications that were done. Are you running a catch can?? whats the pcv system look like and so on. When the car stalls does the EPC light come on??

The tune is being done by a very respected tuner. Haven't changed much accept new adjustments to the file as we increase boost. About to go back 3 or 4 flashes to see if the problem presist. I've done a throttle body adaptation and the same issue. Now the issue with channel 32 is it never changes, as in drive for a couple days and it's the same thing, sitting at 0 in idle and partial. I even called vcds and they don't know why it wouldn't record that channel.
I've done the vacuum delete. Have a simple system tied into a catch can. I don't think the epc light comes on when it stalls.
I posted wrong in orginal post. I was referring to channel 32. Sorry

[PSI NRG]

I know it sounds basic but have you checked for vac leaks?

Also I had a buddy w a big turbo DSM that would want to stall out upon coming to a stop after driving and it was all in the tune. Once the tune got sorted out it was perfect. What software are you using?


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[Audi body]

I know it sounds basic but have you checked for vac leaks?

Also I had a buddy w a big turbo DSM that would want to stall out upon coming to a stop after driving and it was all in the tune. Once the tune got sorted out it was perfect. What software are you using?


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I've done a boost and vacuum leak test. Found a very small leak and repaired. No change.

[Audi body]

Problem solved. In the tuning the maf value was a tad but to high. Backed it up and all good. Thanks for any replies

[EuroxS4]

Glad you got it sorted out.

[A4SoftWalker]

Good to hear.

I just read through this thread and saw you were looking on the O2 side.
I was going to suggest the cold side of your turbo setup.
I recently (Jan 2021) had a problem with MAF scaling and intake g/s readings as well.