Data Logging Results - Anything to worry about?

[42TT]

Took advantage of a nice cool night to take the car for a few runs on the freeway with the Vag-Com connected logging the following paramters:

Data Log 1

MB 002 (RPM, Load, Bank1 g/s, Bank2 g/s)
MB 006 (RPM, Load, Trans Temp, Lambda)
MB 115 (RPM, Load, Req Boost, Actual Boost)Data Log 2

MB 031 (Bank1S1, Bank1S2, Bank2S1, Bank2S2)
MB 020 (Bank1C1, Bank1C3, Bank1C5, Bank1C7)
MB 020 (Bank2C2, Bank2C4, Bank2C6, Bank2C8)From the log's I noticed a few variances between the Bank1 and Bank2 Mass Flow readings (shown in variance) and the Req. Boost vs Actual Boost has a few variances mainly below 3000rpm.

Just wondering if others have done the same and can comment on the data and if there is anything not right.

Please note that i wasnt able to upload the data log's with a .CSV extension so when you view it be sure to replace the .PDF with .CSV

Thanks in advance
42TT

[O.CT USA]

Took advantage of a nice cool night to take the car for a few runs on the freeway with the Vag-Com connected logging the following paramters:

Data Log 1

MB 002 (RPM, Load, Bank1 g/s, Bank2 g/s)
MB 006 (RPM, Load, Trans Temp, Lambda)
MB 115 (RPM, Load, Req Boost, Actual Boost)Data Log 2

MB 031 (Bank1S1, Bank1S2, Bank2S1, Bank2S2)
MB 020 (Bank1C1, Bank1C3, Bank1C5, Bank1C7)
MB 020 (Bank2C2, Bank2C4, Bank2C6, Bank2C8)From the log's I noticed a few variances between the Bank1 and Bank2 Mass Flow readings (shown in variance) and the Req. Boost vs Actual Boost has a few variances mainly below 3000rpm.


Just wondering if others have done the same and can comment on the data and if there is anything not right.

Please note that i wasnt able to upload the data log's with a .CSV extension so when you view it be sure to replace the .PDF with .CSV

Thanks in advance
42TT

Hi

I was looking at your logs and it seemed like there was some correction going in your car. Blocks 020 and 021 showed over 6 CF which isn't safe. Boost wise I don't see any leaks present.

[42TT]

OCT USA: Thanks for your reply. What could cause this? I only ever use high grade fuel.

Could this be and the measured air variance problem be linked? by say a blocked cat on bank1

Thanks alot
42TT

[O.CT USA]

OCT USA: Thanks for your reply. What could cause this? I only ever use high grade fuel.

Could this be and the measured air variance problem be linked? by say a blocked cat on bank1

Thanks alot
42TT

What octane are using? What mods do you have?

[42TT]

OCT USA: Fuel here is 98 Octane and there are no mods to the car apart from the rear mufflers being replaced with resonators for a exhaust note.

[skiwi]

up to 12cf is fine. you have nothing to worry about. over 12cf would indicate issues with the knock sensors or fuel. one think to look for is variance between the sensors.

otherwise, all looks fine. the varance between your g70 and g246 air mass sensors is quite high - but up to 20% variance is "within spec". as a rough rule of thumb, your peak air flow at redline should be 80% of your horsepower.

[42TT]

SKIWI: Thanks had me worried it was leaning out there for while. I have just done some new logs to try and see if the variance can be attributed to a blocked cat so I did the following

Log on cold start (MB002,046,047)
Log on operating temp (MB002,036,037)
Log on operating temp (MB002,046,047)

Unless I am readind the data incorrectly the variance seems to come and go and varies by a significant amount.


I have attached these as a workbook. Again please remane the file to .xls for viewing

Thanks
42TT

[skiwi]

your variance between maf sensors is too high. 1 looks like it might be on the way out...

[42TT]

SKIWI: Yes they are a fair way off. And the problem seems intermittent but I have tried swapping the maf sensors around and it didnt change anything Bank1 still read low also swapped filter elements around. Is there anything else that it would be?

Also should I be concerned about the Measures Boost vs Request Boost log as the Measured Boost seems low in the mid-low rpm range? Or is this a side effect of the MAF variance problem?

To correct my earlier post only mods are aftermarket DV's and removale of rear mufflers for exhaust note.

I greatly appreciate your help on this

[O.CT USA]

up to 12cf is fine. you have nothing to worry about. over 12cf would indicate issues with the knock sensors or fuel. one think to look for is variance between the sensors.

otherwise, all looks fine. the varance between your g70 and g246 air mass sensors is quite high - but up to 20% variance is "within spec". as a rough rule of thumb, your peak air flow at redline should be 80% of your horsepower.

Anything over 6 CF can indicates timing being pulled back or knock. In this case there were no spikes of timing retard ,but constant as you can see on 4 of the cylinders are doing. So say for example the number is 0 means that for each of the cylinder boxes indicates NO timing retard is taking place at all. To sum it up there is no timing that has to be removed by the computer as it senses knock. Most of the time 020, and 021 can be the factors of high egts or other factors such that the ecu will pull back timing.

[42TT]

OCT USA: Thanks for your reply. Does this mean that Bank1 is the 4 cylinders you mentioned that are having timming pulled?

Is there anything else that I can check or log to give you more information to try and find the the problem?

Thanks

[O.CT USA]

OCT USA: Thanks for your reply. Does this mean that Bank1 is the 4 cylinders you mentioned that are having timming pulled?

Is there anything else that I can check or log to give you more information to try and find the the problem?

Thanks

Mmmm well to see if those numbers go down, one of the test I do is to put higher octane and see.

[42TT]

Well the only higher octane fuel up from this is race fuel. What are your impressions on the maf readings?

[O.CT USA]

Well the only higher octane fuel up from this is race fuel. What are your impressions on the maf readings?

I need to log block 002 on my car and see. The only logs I have on my car that is MAF related is 003 though.

[42TT]

OCT: Well according to ELSA the variance should <20% and from my data i have a variance>20%. I have been told it could be a vacum leak all the way through to a blocked cat or dying turbo.

As far as the ecu receiving knock and pulling timming. Is there any way to log actual timming vs requested timming and see at what rpm/load the ecu is pulling timming?

Not sure if this is related but a few weeks ago i had a DTC for Bank1 Exh. Temp Sensor - Implausible reading but after being cleared that hasnt come back again.

Thanks
42TT

[Radiation Joe]

This is from an TT S4 dyno run, but gives you an idea of what you can sample. I don't know how to gather the info, though.

sample parameters (http://www.flwse.com/images/steve/Audi_Tech/ECUx/4runs_compare_graph_chris.htm)

[skiwi]

if you have swapped the maf's around and the values don't move with the maf, then you can discount them. ditto the air filter elements.

that leaves vacuum leaks. the maf seals would be the obvious place to start. have you checked those?

[42TT]

Will do so today and report back

Thanks
42TT

[42TT]

I have checked the maf sensor seals and they look fine. I also tried building up the bottom of the maf that sits against the seal to see if it made a difference and it didnt.

I will start looking at other possible areas of vacum leak starting the the air injection system. Once thing I did notice is that the exhaust temp sensors may be back to front. Bank1 uses Brown and Bank2 uses black from memmory is this correct? If it is somehow mine are back to front

42TT