VCDS logging suggestions on what to log.

[Westy]

I'm planning on doing some logging this Saturday morning (if I can drag my lazy **** out of bed!) to try and diagnose a possible boost leak/failing MAF. When I get my toe down I can hear the turbo and it sounds like normal but the car seems to have lost the kick it had before.

I plan to log the following blocks and wondered if anyone had any others to add to the list:

- Block 1
- Block 2 = MAF
- Block 20
- Block 31
- Block 115 = Boost
- Block 118 = N75 Cycle

All of the above should give me an idea of boost, MAF, Fueling, rough power figure etc.

If anyone has any other suggestions please post here.

 

[s3dave]

http://www.ross-tech.com/vag-com/m_blocks/

 

[Westy]

Thanks for that link Dave but I was more after peoples experiences of logging to diagnose power issues. I'm kind of hoping my MAF readings are low and by unplugging the MAF will confirm its the MAF. It's an easy fix then.

 

[J B]

I am very much in the same boat, think my MAF has given up the ghost but was wondering how to confirm it with VCDS!?

 

[badger5]

std 210/225 should read 180g/s and remapped 200-210g/s approx

substantially less and its goosed
also check (not log) block 032 and see what fuel trims are at (before erasing any faultcodes, as that also resets adaptions on 032)

 

[Westy]

Thanks Bill. How long do MAFs tend to last on a remapped car in your experience? My MAF is nearly 3 years old!

 

[J B]

Im not aware that my MAF has ever been changed lol! I had a peak of 138g/s this afternoon and thats after fitting Bills 3" TIP & a big old JR cone! think I will be giving audi a call then

 

[Westy]

JB have you got an S3, it looks like it from your pic? If you unplug the MAF and re-do your logging your car should use the default values of the ECU instead of the MAF reading (as its unplugged). If you've got a more powerful car, you know your MAF is fecked.

This is a cool spreadsheet to use to get a rough power graph: http://www.ross-tech.net/vag-com/examples/Block_120_Tutorial.xls

 

[J B]

Yeah its an AMK, I might give this a go in a minute then I have just ordered a MAF from audi anyway hopefully this will just confirm! Is there anything I should log whilst doing this?

 

[badger5]

remembering back to the RR day we did... there was an S3 on that day which had barely over 100g/s from his MAF - it happens.. quite often

 

[Westy]

I might unplug my MAF for the drive home to see if it feels any different!

 

[Westy]

Just logged my boost, MAF, and power on my way to get my exhaust fixed. Anyway I had a quick peek at the maf reading while logging and the max I saw was 188 on a stage 1 S3!!!! That might explain my lack of power. I'll have to check the boost readings when I'm home to see if there's a leak but somethings not right!

 

[Westy]

Went to Audi and got a new MAF which has made the car feel so smooth but something is still wrong as I'm getting the same reading on the new MAF! Heres the results of Blocks 2 (MAF), 115 (Boost), 120 (Power):

Old MAF:

MAF = 188g/s
BHP = 244
TRQ = 270lbft
BOOST = 22PSI

Unplugged MAF:

MAF = N/A
BHP = 245
TRQ = 260lbft
BOOST = 22PSI

New MAF:

MAF = 187g/s
BHP = 229
TRQ = 268lbft
BOOST = 22PSI

HELP! WTF is going on? If the MAF readings are that low with a new sensor and on a car that is holding 22PSI what else could the problem be??

Any help appreciated.

 

[Westy]

Just noticed that this error is reocurring:

17963/P1555 - Boost Pressure Control: Upper Limit Exceeded

Possible Symptoms

• Reduced power output
• Limp mode

Possible Causes

• Boost Pressure too High
• Hoses/Pipes incorrect connected, disconnected, blocked or leaking
• Charger Pressure Control defective
  • VNT (variable nozzle turbo): nozzles stuck
• Solenoid Valve for Boost Pressure Control (N75) defective

Possible Solutions

• Check Hoses/Pipes to/between Components
• Check Solenoid Valve for Boost Pressure Control (N75)
• Check / Clean / Replace Charge Pressure Control
  • Check / Clean mechanism for variable nozzles

I think i'll go away and log the N75 cycle and see if thats the culprit.

 

[Westy]

Right i'm going to log the N75 duty cycle this evening and just want to make sure i'm on the right track.

From my understanding I should be logging block 118 along side 115 to show the boost as well as the N75. The N75 should hit around 96% to show spool up then wind back while it achieves its requested boost. Anyone else done N75 logging before?

 

[s3dave]

I dont think they go past 95% as a safety measure...irc

 

[Westy]

Ok I logged the N75 and it seems fine as it's peaking at 94.5%

Soooooo, what could my problem be? What else would cause low MAF readings if the MAF is brand new? Small boost leak possibly?

 

[finesse]

1 . 002 115 119

2. 032 (both values, when idling)

 

[Westy]

What's block 119? I have a file of 002, 115, & 118 to show MAF, Boost & N75

What does block 032 show?

 

[Westy]

Also does anyone know what the "charge pressure control" is?

The code above says to try the following:

Possible Solutions

- Check / Clean / Replace Charge Pressure Control

 

[finesse]

What's block 119? I have a file of 002, 115, & 118 to show MAF, Boost & N75

What does block 032 show?

032 adaptations made because of vac leaks etc



Boost pressure control

Duty cycle boost pressure control valve vs Boost pressure before throttle valve

 

[finesse]

Fault Code: 17965 Charge Pressure Control - uk-mkivs

 

[Westy]

Thanks Finese but still doesn't explain what or where the charge pressure control is to clean or change it.

I'll log 032 tomorrow and see whats occuring. Cheers

 

[Sandip]

Your maf reading are very similar to what i got a few months back, what map are you running?

I had loads of leaks when i got 188g/s. Most of my pcv hoses were split plus my cylinder head was cracked

 

[Westy]

Your maf reading are very similar to what i got a few months back, what map are you running?

I had loads of leaks when i got 188g/s. Most of my pcv hoses were split plus my cylinder head was cracked

That's not what I want to hear! My PCV system was changed in the summer when I fitted my catch can, maybe there is a leak in my new system? I'm running a ChippedUK map from "Chip n spin".

I logged block 32 as suggested above but not sure if it's the right block as it's showing Lambda 1.3% & -0.8%

 

[finesse]

results are fine

Easiest way is to check block 032.

There are two fields in the block, and both belong to fuel trims.

Left hand one is short term adaption, right hand one is long term adaption. Left hand one is the one to look at in this instance.

Make a note of these two figures. Reset the fault codes (even if there are none), as this will clear the fuel trim data back to 0% for both blocks.

Then start the motor and log block 032. If the value in the left hand block steadily climbs to or past the 3-4% area, it's normally a good indication of a leak.

 

[s3dave]

Charge pressure control would be the actuator....

 

[Westy]

Ahhh nice one cheers. So the above is an indeication of leaks within the FRP if it is measuring fuel trim?

So it looks like my next port of call will be PCV and boost hoses.

 

[Westy]

Charge pressure control would be the actuator....

Any way of using VCDS to log what the actuator is doing? I'll try to post up my boost graph in a minute.

 

[badger5]

032 adaptations made because of vac leaks etc

and other scenarios like maf under reading, and lambda correcting afr

 

[s3dave]

could try the hose from n75 to actuator, sometimes are loose on the actuator

 

[Westy]

and other scenarios like maf under reading, and lambda correcting afr

Bill, If my boost readings seem fine, and so do my Lambda but my MAF (brand new) readings are low where would you start hunting for problems?

 

[Westy]

Ok here's my graph showing boost on the old MAF and the new MAF. The lines will be slightly different anyway as the runs were logged on 2 different stretches of road. As you can see the boost seems to tail off pretty quickly, could this be a tired actuator??

 

[S3KO4]

I have logged the the above mentioned blocks:

I have got the following:

gs= 202
BHP = 202/0.8 = 252
torque= 325nm out of a possible of 435!
psi= 23.3

why is the torque down so much. I would have thought it would be near the 400 mark! and the bhp is down by 10

test was done using 3rd gear with shell v-power, both oil and coolant temp were both 90C

 

[s3dave]

I would think the torque is enough.....maybe slightly down on the g/S readings...

 

[Westy]

I have logged the the above mentioned blocks:

I have got the following:

gs= 202
BHP = 202/0.8 = 252
torque= 325nm out of a possible of 435!
psi= 23.3

why is the torque down so much. I would have thought it would be near the 400 mark! and the bhp is down by 10

test was done using 3rd gear with shell v-power, both oil and coolant temp were both 90C

Put your torque figures into this spreadsheet to get lbft:

http://www.ross-tech.net/vag-com/examples/Block_120_Tutorial.xls

You've got to remember that the readings are all from sensors and not a true representation of your actual Torque if you were to get on a RR.

 

[s3dave]

Put your torque figures into this spreadsheet to get lbft:

http://www.ross-tech.net/vag-com/examples/Block_120_Tutorial.xls

You've got to remember that the readings are all from sensors and not a true representation of your actual Torque if you were to get on a RR.

Unfortunately a lot of RR arnt true representations either....lol

 

[Westy]

Unfortunately a lot of RR arnt true representations either....lol

haha very true.

 

[S3KO4]

There is only one way to find out. a side by side drag race..

 

[S3KO4]