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Author Topic: Me7.1 limp mode  (Read 168 times)
Jugoo
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« on: June 05, 2018, 05:48:08 AM »

Hi!

Does anyone here know all or the most common causes in S4 B5 stock C-Box for limp mode?

  • Bad maf reading?
    • N75 duty cycle?
      • Actual vs ordered boost pressure not matching = boost leak
        • EGT reading too high?
          • what else....?

          • I thought that this forum is the Place to ask this question, because knowledge about me7.1 coding.

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adam-
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« Reply #1 on: June 05, 2018, 07:44:16 AM »

Why does it matter?  Read the code and know exactly.
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nyet
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« Reply #2 on: June 05, 2018, 08:55:15 AM »

The most common cause is the one that tells you the problem.
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ME7.1 tuning guide (READ FIRST)
ECUx Plot
ME7Sum checksum checker/corrrector for ME7.x

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience.
Jugoo
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« Reply #3 on: June 05, 2018, 10:27:37 AM »

Why does it matter?  Read the code and know exactly.

I wouldnt be asking this if any DTCs would be left.
After WOT boost drops from 1bar to 0,5bar. No DTC even read limp mode and car running. C-box is not showing EGT values in vcds. Boost leak test is made.

This is why I ask this question.
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nyet
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« Reply #4 on: June 05, 2018, 10:28:29 AM »

Provide logs.

Do not post VCDS logs. Use ME7Logger.
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ME7.1 tuning guide (READ FIRST)
ECUx Plot
ME7Sum checksum checker/corrrector for ME7.x

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience.
Jugoo
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« Reply #5 on: June 10, 2018, 04:42:20 AM »

Hey nyet, heres graphs from logs. I attach also the .csv files so if you could look at them also.

Thank you.

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nyet
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« Reply #6 on: June 10, 2018, 09:41:23 AM »

Looks like positive deviation limp (underboost) and/or i-max trim limit reached.

Would have to log i-limit and associated trims to be sure.

Make sure you don't have a boost leak

Check LTFTs to make sure they're sane

Increase IMX
« Last Edit: June 10, 2018, 09:44:55 AM by nyet » Logged

ME7.1 tuning guide (READ FIRST)
ECUx Plot
ME7Sum checksum checker/corrrector for ME7.x

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience.
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