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Thread: MAF readings discrepancies

  1. #11
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    From the tone of your reply I clearly must have missed something. Is that a forum rule not to talk about remaps, or have shown disrespect?

    Of course you don't have to reply, but my understanding is that MAFs readings in g/s as seen in VCDS are a calculation based on the signals sent by the MAF, so were you implying VCDS don't have access to these 'lower level' calculations, like a program on any computer don't have access to the underlying Operating System operation?

  2. #12
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    Quote Originally Posted by Larry Manton View Post
    CLASSIC, okay most mostly a TDI guy but As I see it. Cold engine might be tighter then as warms tolerances fade. That is making assumption each bank has its own MAF, could be wrong.

    Would be looking at compression check. As have no scan DON'T
    know mileage wear factor here?

    Would suspect one bank not as efficient as the other, just an opinion.

    Also post an auto scan as you will be requested to do so as were only as brite as the info we have?

    Good hunting

    LARIMORE
    Missed your post Larry, thank you. Yes I have 2 MAF, one per bank. Good point, but wouldn't that efficiency mismatch be seen somewhere down the line, I don't know like injectors duty cycles or lambda readings (the latter are perfectly matched by the way)?

    Regarding the full auto scan, I'll definetely comply to the rule (away from home for a week or so, but will be done on my return), but as the only engine fault code is this MAFs mismatch I though appropriate (probably wrongly) not to bother with the rest.

  3. #13
    NostraJackAss Jack@European_Parts's Avatar
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    Okay look at it this way.
    VCDS can only see what the controller permits it too.
    If hardware or in this case the ECU is remapped than the data that is or isn't displayed would be foolish to rely on.

    The RTFB is a guide for an unmodified vehicle, therefore care and specs of the mods would be wise to ref.
    There are no substitutions for actual mechanical or electrical tests.

    OBD data is a guide, not a single catch all for doing proper repairs stock or modified. A cross check of data or hardware is REQUIRED and advised when seeking proper repairs.
    European Parts Emporium/Performance / Immobilizer Solutions EPE
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    Above Magic! No Written record, AUTO-SCAN or Appointment = NO HELP!
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  4. Likes Classik liked this post
  5. #14
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    Quote Originally Posted by Jack@European_Parts View Post
    Okay look at it this way.
    VCDS can only see what the controller permits it too.
    If hardware or in this case the ECU is remapped than the data that is or isn't displayed would be foolish to rely on.

    The RTFB is a guide for an unmodified vehicle, therefore care and specs of the mods would be wise to ref.
    There are no substitutions for actual mechanical or electrical tests.

    OBD data is a guide, not a single catch all for doing proper repairs stock or modified. A cross check of data or hardware is REQUIRED and advised when seeking proper repairs.
    Thanks for taking the time, appreciated. So to be clear I need to double/tripple check with my mapper that the supposed OEM map is indeed correct before chasing my tail on this issue. Makes totally sense, but in my defense I wouldn't have even envisaged their OEM map could be faulty. Need to educate myself about the difference between switched map vs reflashed map, so take my former response with a full spoon of salt..

  6. #15
    NostraJackAss Jack@European_Parts's Avatar
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    Get real second factory test ecu or file than compare binaries to see if consistent with each other.

    You may enjoy this link.
    www.evc.de
    European Parts Emporium/Performance / Immobilizer Solutions EPE
    Certified Master Trained NY/BAR/BAD 7076062/ASE/SAE/NASTF Legal Factory Authorized/Licensed GeKo/FaZit # 403738
    Specializing in Custom Services IE: "welding-fabrication" / EPA-SMOG Update or Pass-Thru-Programming / Data Transfer / Immobilizers & OEM Quality Parts
    Above Magic! No Written record, AUTO-SCAN or Appointment = NO HELP!
    www.FixMyEuro.com <<<<<CLICK HERE! or vwemporium@aol.com ( JPPSG & Unverified members need not PM me & Please don't email or call facility for free tech support...use the forum )
    Getting you CONTROL again of your property - TAKE IT! In Conjunction with.........

  7. #16
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    Quote Originally Posted by Jack@European_Parts View Post
    Get real second factory test ecu or file than compare binaries to see if consistent with each other.
    www.evc.de
    I guess I'll start with the latter, thanks.

    Quote Originally Posted by Jack@European_Parts View Post
    You may enjoy this link.
    www.evc.de
    Confirmed, many things to learn!

  8. #17
    NostraJackAss Jack@European_Parts's Avatar
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    European Parts Emporium/Performance / Immobilizer Solutions EPE
    Certified Master Trained NY/BAR/BAD 7076062/ASE/SAE/NASTF Legal Factory Authorized/Licensed GeKo/FaZit # 403738
    Specializing in Custom Services IE: "welding-fabrication" / EPA-SMOG Update or Pass-Thru-Programming / Data Transfer / Immobilizers & OEM Quality Parts
    Above Magic! No Written record, AUTO-SCAN or Appointment = NO HELP!
    www.FixMyEuro.com <<<<<CLICK HERE! or vwemporium@aol.com ( JPPSG & Unverified members need not PM me & Please don't email or call facility for free tech support...use the forum )
    Getting you CONTROL again of your property - TAKE IT! In Conjunction with.........

  9. #18
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    I've just read the first 10 posts, sounds promising
    For that matters sai and evap are fully operational here, admittedly reduced cats (200 cells) but most of the time I'm running on e85, except when troubleshooting my MAFs discrepancies issue..

  10. #19
    NostraJackAss Jack@European_Parts's Avatar
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    I've just read the first 10 posts, sounds promising
    For that matters sai and evap are fully operational here, admittedly reduced cats (200 cells) but most of the time I'm running on e85, except when troubleshooting my MAFs discrepancies issue..

    So you have drank the Kool-aid......?

    The difference between "True Motorsports" and just delete or defeat devices is where you have to consider is the SMOG device really hindering an alleged performance characteristic or is it that someone can't tune or is lazy and they direct you to delete it & because they set a control table to ZERO?

    No real rocket science to setting stuff to zero huh, is that to be respected?


    I guess my question to you and any of the tuners is, if the engine is running allegedly more efficient after one of these tunes and with harmonious combustion, why would you have to delete the CAT or readiness monitors and if you didn't remove the physical CAT, why would the CAT exhibit shortly after such a tune & at a 99% failure RATE on an actual factory CAT & being completely damaged, restricted or plugged?
    Last edited by Jack@European_Parts; 04-20-2019 at 05:12 PM.
    European Parts Emporium/Performance / Immobilizer Solutions EPE
    Certified Master Trained NY/BAR/BAD 7076062/ASE/SAE/NASTF Legal Factory Authorized/Licensed GeKo/FaZit # 403738
    Specializing in Custom Services IE: "welding-fabrication" / EPA-SMOG Update or Pass-Thru-Programming / Data Transfer / Immobilizers & OEM Quality Parts
    Above Magic! No Written record, AUTO-SCAN or Appointment = NO HELP!
    www.FixMyEuro.com <<<<<CLICK HERE! or vwemporium@aol.com ( JPPSG & Unverified members need not PM me & Please don't email or call facility for free tech support...use the forum )
    Getting you CONTROL again of your property - TAKE IT! In Conjunction with.........

  11. #20
    Benevolent Dictator Uwe's Avatar
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    Quote Originally Posted by Classik View Post
    From the tone of your reply I clearly must have missed something. Is that a forum rule not to talk about remaps, or have shown disrespect?
    No, there is no such forum rule. That's just Jack being Jack.

    Now remaps do make trouble-shooting more difficult. I've seen it myself where a car with stock software ran pretty well, but "tuned", it was horrible, and the source of this was eventually traced to a small vacuum leak. So a "mapped" ECU can behave quite a bit differently. In addition, some tuners seem to think it's necessary or desirable to disable certain tests for faults...

    Quote Originally Posted by Classik View Post
    Of course you don't have to reply, but my understanding is that MAFs readings in g/s as seen in VCDS are a calculation based on the signals sent by the MAF, so were you implying VCDS don't have access to these 'lower level' calculations, like a program on any computer don't have access to the underlying Operating System operation?
    Those calculations -- turning analog sensor readings into something resembling real-world values like g/s -- are done by the ECU, not VCDS. Now the digital value that the ECU sends to VCDS may still not be g/s, but that conversion will be some well-understood formula that isn't likely to be wrong, especially on 2003 car.

    -Uwe-
    The engineering problems are likely insurmountable. It would be like proposing to land a rocket booster section on a barge floating in the middle of the ocean.

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