Help with VAG-COM : Sluggish Performance

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My S3 has been pretty sluggish as of late. Feels like it takes ages to get moving and when you take your foot of the gas it feels like its' pulling back instead of just rolling. Also, on startup from cold the rev counter hunts from about 1100 until it makes its' way down to 900 - I'm pretty sure it didn't always use to do this.

I got the car checked for air leaks a few weeks ago. Any leaks were fixed up. The car was great after this for about 4 days and then back to sluggish performance.

Below are some figures from VAG-COM. Can anyone spot anything?

• My g/s levels are around 195. Whereas before they were 210. That a little under a 10% drop - not sure if they would cause the poor running?
• Boost looks ok I think?
• Hardly any correction factor either - there used to be quite a lot last time I logged.
• I couldn't find any info on how to interpret blocks 001. 031, or 118 for N75.

 

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Any ideas folks? I got the car checked for air leaks again - no leaks! Also got the throttle body realligned again and learned values wiped. But still not better.

The main symptoms are:

1) It takes a lot longer for the turbo to spool up than before....so feels really sluggish and dead in comparison to how it was.
2) When driving in higher gears and taking the foot of the gas you can feel some resistance, as if the car is pulling back, rather than rolling smoothly.
3) When driving in 1st gear, if you take your foot of the gas instead of rolling smoothly, the engine is jumpy.

None of these symptoms existed when I initially got the air leaks fixed. It pulled really strong from about 2.5k revs and it was totally smooth in first gear when lifting of the gas.

 

[Greig300]

Thing is you really need to take your car to an audi specialist. Because someone could tell you it could be one thing and it was another.....and your left to spending money on your car. Take it to someone who can see it physically and drive it explain your problem face to face. Then you can get it repaired. Hope this helps otherwise you could possibly be on here and researching for a while.

 

[s3_stig]

Could be the maf

 

[<tuffty/>]

Running very rich before it gets on boost... would imagine thats the reason why it feels a bit sluggish...

<tuffty/>

 

[metricspaces]

Running very rich before it gets on boost... would imagine thats the reason why it feels a bit sluggish...

<tuffty/>

Thanks tuffty. What would cause it to run rich do you think?

Which part of my logs show it is running rich - just so I know what to look for myself in future.

 

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Ah, a quick read of Ross-Tech: VAG-COM: Fuel Trim Info I think tells me that it is block 031 that tells you that I am running too rich.

This page says the following:

when we need acceleration, the mixture gets richer. Why? Maximum power is made between 0.85 to 0.95 Lambda (12.5 to 14.0 A/F with iso-octane). So, under acceleration, mixtures get richer. Sometimes you want to get even richer under acceleration to keep detonation (pre-ignition of the mixture from excess cylinder temperatures) away. The 1.8T has a relatively high compression ratio for a turbocharged engine, which especially under lots of boost, is very succeptible to detonation).

So my values for block 31 are definitely less than 0.85.

What would typical values be for a stage 1 S3 under wide open throttle acceleration in third gear? The quote above says you might want to have a richer mix than 0.85. So just wondering how far my values are off by?

 

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I just did some searching on the forum there. I saw some advice from Bill here about the values you'd expect in block 031. He suggests between 0.8 and 0.85 under boost. http://www.audi-sport.net/vb/a3-s3-forum-8l-chassis/86479-help-vag-com-data-graphs.html

From 1440 RPM all the way up to over 3000 RPM I am under 0.8. So I guess this is what you were referring to Tuffy?

Now my question is, what would be causing this? There's definitely no air leaks in the system and all learned values were wiped, yet it is still not performing like it did after I initially got some leaks in my breather hoses fixed (throttle body was realligned as part of this work, and learned values wiped).

 

[metricspaces]

Some more searching about common problems with 1.8T 1.8T Common Troubleshooting Guide on Audi, Seat, Skoda and Volkswagen Tuning Support Forum. provides me with this info:

Running Rich – Boost Leak, MAF, O2 Sensor, Coolant Temp Sensor

I think I can rule out a boost leak. So that leaves MAF, 02 Sensor. Coolant Temp sensor.

My MAF readings are down on what I have seen before. The max I could get this time was 197g/s. The max I got last year was 210g/s.

I've previously replaced the MAF and CTS. But I guess for peace of mind here, the simplest thing is just replace all three and getting logging again ? What you reckon Tuffty?

 

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I just checked block 032. Here are the values:

Idle Value = 2.1%
Part Throttle Value = -0.8%