S3 problem

[squale]

Hi all,

I have a problem on my S3. It is ABT chipped with a full catback inox exhaust. I have a problem, the resquested boost isnt reached when i log into vag-com. So the car feels slower and rev slowly in high gears (4, 5th and 6th)
I cant go to the max speed anymore.

I replaced the DV, the n75 & installed a samco induction hose. Nothing changed.

btw I checked the maf :

rpm load avg inj time MAF g/sec
6200 164.7 16.66 192.08
6400 151.1 15.98 186.39
6640 142.9 14.62 178.17
6800 135.3 13.94 179.33

Any ideas ? I have other logs if needed.

thx a lot !

 

[AL_B]

Hi,

Looking at the data there, 186, 192 g/sec looks a bit low for a remapped car. So it could be your MAF.

I'm sure others with chipped motors will post soon.

AL

 

[JamS3]

I have a similar problem in 4th 5th and 6th gear, you can hear the turbo and dv spin up. My boost gauge goes to about 18psi (accelerating from around 2000rpm) but there seems to be a hesitation between the boost spinning up and seeing it register on the gauge and actually feeling the power accelerate you forward, about a second delay??

Any ideas anyone?

 

[squale]

@AL_B : thank you, do you know how much it could be ?

@JamS3 : Yes i go the same problems, feeling like a step in power up.. not all the time.

If anyone could post maf & boost readings ?

thx

 

[JamS3]

I just bit the bullet today and bought a new MAF.

Seemed to have made the car rev more smoothly with the power coming on a bit earlier under very light throttle.

Think my old MAF was on the way out but not enough to throw a fault up on vagcom

 

[242spot]

Mate i had almost the identical problem two weeks ago. Turned out to be my fuel pump, the car was leaning at the top end. Get down to you local rolling road have the exhaust gas mixture checked.
I changed dv n75 cleaned injectors water temp inlet temp maf the list goes on... FEUL PUMP was the trick though.
email me im happy to share my Vagcom plots with you so you can compare,
scottwells@fastmail.fm

 

[claudefrog]

gosh.. i have the same prob in 4th 5th and 6th on my remapped car, it feels rather sluggish compared to 1st 2nd and 3rd

may have it checked out

 

[JamS3]

Tracked my problem down to the DV, see the post about Diverter Valve q's

 

[squale]

Tracked my problem down to the DV, see the post about Diverter Valve q's

Already put a new OEM one, didn't solved..

thx anyway

 

[squale]

After all, i am pretty sure that i have a boost leak, does anyone knows the best method to locate the leaks ?

thx

 

[JamS3]

Soapy water (somthing like fairy liquid) sprayed all over the hoses the air leak will cause bubbles to form!

 

[squale]

Finally i got some starting problems, sometimes when i start the car I do not hear the fuel pump starting (the 'bzzzz' noise) and the car doesn't start (especially when on the first start the morning), and i must retry one or two times to get it started. Changed the fuel pump relay but doesn't solved.
I guess to my performance figures explained upper are related to this problem ?

I am thinking about replacing the fuel pump itself, as it seems to be erratic, anyone knows how to check the fuel pump ?

thanks !!