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Anyone know how to read/translate a VAGCOM Log???

Discussion in 'A3/S3 Forum (8L Chassis)' started by Nilz, Sep 2, 2010.

  1. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 2, 2010]
    As the title says really.

    Did some logging on the car tonite as im having a slight misfire/hesitation on acceleration.

    Just wanted to know if anyone on here can explain what it means, if I was to put the log up.

    Let me know and I will add it accordingly.

    Thanks
    Nilz
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  3. jojo
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    jojo Looking for Boost! Staff Member Moderator

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    [Sep 2, 2010]
    I'd like to know too. :laugh:
    #2
  4. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Sep 3, 2010]
    what have you actually logged data block wise?
    you checked Ross-Tech: Home site out first yea for how to use the software?
    #3
  5. S3 TAM
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    S3 TAM Pocket now empty

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    [Sep 3, 2010]
    Just read the thread yeah put them up.
    #4
  6. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 3, 2010]
    Sorry guys, how do i put them up here??
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  7. S3 TAM
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    [Sep 3, 2010]
    did you save the log to a txt file?

    If so just copy and paste the txt out of the file.:thumbsup:
    #6
  8. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Sep 3, 2010]
    Screenshot in excel.... best way is to freeze the top rows with the header info in, scroll to the part of the log where you started the run and screen shot that... below is an example from one of Sandips's logs he sent me...

    [​IMG]

    <tuffty/>
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  9. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 3, 2010]
    Cheers Guys, I will do that shortly, its been saved as a CSV file.
    #8
  10. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 3, 2010]
    [​IMG]

    Is this ok??
    Last edited: Sep 3, 2010
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  11. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 3, 2010]
    [​IMG]

    Got this one too....
    #10
  12. jojo
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    jojo Looking for Boost! Staff Member Moderator

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    [Sep 3, 2010]
    It was a 15-20 minute log by the way guys, as it was my first time logging. I did 2 logs, the 2nd one was 5 minutes or so, but I have put a few markers in the logs, but alas, I don't know how to use the data.
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  13. S3 TAM
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    [Sep 3, 2010]
    looking at the first one. it looks like your MAF is playing up.

    Engine load to how much air the car is sucking in. looks wrong in some places
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  14. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 3, 2010]
    Jag, thanks mate, how did you work this out, what is it you are looking for, excuse my ignorance, we are newbies to this and just sort of went for it really!!! LOL
    #13
  15. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Sep 4, 2010]
    I can't really see the pics but I would change your coolant temperature sensor. Unless you done this test when your engine wasn't at operating temperature your readings are wrong. Your temperature readings are a lot lower than they should be so your ECU will be throwing in more fuel as it thinks its still in the warm up phase.

    Nathan
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  16. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 5, 2010]
    Hey Nath, thanks for your comments, what bit are you looking at to get that info, as the car was running at normal temp and was showing this on the log as well.

    The 1st log showing 73 was done on the motorway, and the 2nd one was just shortly after leaving the house and is showing 79 i think.

    Would that be causing the issue im having??
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  17. Welly
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    Welly VX220 SC Driver :)

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    [Sep 6, 2010]
    Should be 85 - 90 at all times during normal running....
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  18. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 6, 2010]
    Ive noticed on mine for quite a while now that after a run on the motorway, it does go down to between 80 and 85.....
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  19. S3 TAM
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    [Sep 6, 2010]
    sounds like you defo need one then it should sit on 90 all the time. mine don't budge from 90 once there. but i don't think that is causing the problem your having. i never had the problem when my temp sensor was broke.
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  20. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Sep 6, 2010]
    Nilz mate, drop me a pm if you are still stuck and give you my email addy to email the csv's so I can have a butchers

    <tuffty/>
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  21. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Sep 6, 2010]
    the fact that the temperature drops when driving quickly (ie motorways) indicates to me the Thermostat is faulty, rather than the CTS.

    Change the stat first.

    At no point in your logs do you actually take the car up the revs? You've also not logged throttle angle, so we cant really see when you stick the boot down.
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  22. S3 TAM
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    [Sep 6, 2010]
    Yes i agree You need to change the Thermostat. Mine was the same fast driving did the same thing to temp on mine before i change the Thermostat.
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  23. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 6, 2010]
    Whats a CTS??

    I will look into the temp sensor and thermostat then and see if its this causing the issue, although as mentioned, you guys dont think its this causing the issue.

    Is the MAF easy to disconnect, also my car is an AMK, if I was to test with someone elses, does it have to be an AMK engined S3, or will any do??
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  24. S3 Nattie
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    [Sep 6, 2010]
    CTS - Coolant temperature sensor. If the temp gauge is 90 degrees but your vag com readings are quite a bit less then its your sensor at fault but if your temp gauge goes down when your on a motorway etc then your thermostat is at fault.

    Do a log from 2000 rpm to redline in 3rd while logging block 003, 031, 115 for the MAF, Lamdba and boost figures and upload your data.

    Nathan

    Edit, was reading the wrong vag com data. Was readings sandips.
    Last edited: Sep 6, 2010
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  25. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 6, 2010]
    Aaah cheers dude

    That makes sense....

    Will have a go at logging when the main man is free again.

    Cheers
    Nilz
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  26. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 9, 2010]
    Had a go at some more logging last night, did blocks 003, 031, 115.

    Please see the log below and let me know what you think.

    Thanks in advance.

    Nilz

    [​IMG]
    #25
  27. Welly
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    Welly VX220 SC Driver :)

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    [Sep 9, 2010]
    @ Nilz,

    Air flow readings are a bit down on what I would of expected to see on that log dude - what map is on the car?
    #26
  28. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 9, 2010]
    Cheers for the quick response Welly, its on a standard map mate, nothing at all done to it.
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  29. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    [Sep 9, 2010]
    Your logs look fine to me for a standard map. Your MAF values are good and your lambda is doing what its asked and your making the boost your ECU is requesting.

    Nathan
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  30. Welly
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    Welly VX220 SC Driver :)

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    [Sep 9, 2010]
    LOL, that would explain the air flow then. In fact, it goes the other way, that's good figures for a standard map. Whats the engine code? BAM I presume?

    Anyway, what is the problem you're trying to fix here? The hesitation on acceleration?

    If so, I would say you are more likely to be the victim of a good old fashioned mechanical problem rather than software. I would be looking for a vac/boost leak somewhere if it were me.

    I would also be looking at your fuel trim data on block 032 rather than 031. 032 tells you short term (left) and long term (right) fuel trims. Can you have a look at that block and tell us what the figures say there?

    Trap for new players here is to NOT reset your fault codes before doing this - it will reset the data in block 032.
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  31. Welly
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    Welly VX220 SC Driver :)

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    [Sep 9, 2010]
    ^^ I agree, spot on.
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  32. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 9, 2010]
    Hey guys, thanks again.

    Its actually an AMK 210bhp Engine....are my figures good then?? :)

    So everything seems to be ok then guys, from an electrical POV yea??

    Whats the fuel trim thing you talk about, we can log that when we get a chance and put that up if it helps??

    And yes it is the hesitation on acceleration that im trying to get sorted.
    #31
  33. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 9, 2010]
    Oh forgot to ask, what the best way of looking for a vac/boost leak.

    Think my thermostat needs doing as well, as driving about last night the car temp on the dash was dropping down to about 80 after a decent run.

    Would that have an effect/cause this??
    #32
  34. Welly
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    Welly VX220 SC Driver :)

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    [Sep 9, 2010]
    best way is to visibly check all the hoses - especially around the inlet manifold.

    Temp..... Potentially yes - the ECU reading temps of ~80 will make it think the engine is colder than it is - putting the fuelling all to cock.
    #33
  35. Welly
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    Welly VX220 SC Driver :)

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    [Sep 9, 2010]
    Figures are good from a 210. I guess you must have some small mods here and there?

    Max G/S on the log is 184.72. This, using the VAG COM BHP Calc method...., equates to 184.72/0.8 = 230.9 BHP.

    Fuel trims are the ECU's adaptation to the engine's fuelling requirements. Simply, the ECU uses the Lambda to review the gases coming out of the engine. Based on what it sees, it either puts fuel in if the mixture is lean, or takes it out if rich. It makes a log of this in block 032 and this data is what you will be seeing.

    There isn't anything to log with regard to the fuel trim - look at Measuring block 032 and make a note of both figures. Then post them. Ideally, both should be as close to 0% as possible. Figures in that block can be both positive and negative depending on what the ECU is doing.
    #34
  36. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 9, 2010]
    OK cool, I will do that this weekend and see if i can change the stat as well, is it the green one that im meant to be going for??
    #35
  37. Welly
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    Welly VX220 SC Driver :)

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    [Sep 9, 2010]
    Ummm, I think there may be a spot of confusion here.

    The coloured things - i.e Back/Green - are the coolant temp sensors. They live on the right hand side of the head in a plastic pipe. This sends the ECU data on the coolant temperature.

    The thermostat on the other hand, is over by the alternator, between the block and another plastic water pipe. The thermostat is a wax based valve effectively, that opens when the coolant reaches the correct temperature.

    By the sounds of your problem - i.e temp dropping on the motorway, it is in fact the thermostat, not the Coolant Temp Sensor (CTS). Basically, the thermostat is opening at the wrong temperature. Common 1.8T fault. Thermo stats can be bought here: Audi - Euro Car Parts UK. Not easy to fit however - very fiddly. Guide here: Thermostat replacement procedure..>> - AudiWorld Forums. Not for the S3, but same procedure.
    #36
  38. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 9, 2010]
    Oh cool...woohoo, im pleased with those figures, honestly, nothing has been done to the car at all.

    I will have a look at those figures and let you know what they say in a few days when we get a chance to get it on VAGCOM again.

    Really appreciate your help and advice guys.

    Nilz
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  39. Nilz
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    Nilz Defo worth the wait :)

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    [Sep 9, 2010]
    Yea i was getting a bit confused with those two...lol...DOH!!!

    OK cool, will look at that this weekend and see if it makes a difference.
    #38

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