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Chipped but only 12psi

Discussion in 'A4/S4 forum(B5 Chassis)' started by turbonutterb, Feb 14, 2009.

  1. turbonutterb
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    turbonutterb New Member

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    [Feb 14, 2009]
    Hi,I am only boosting 12psi insted of 15-18.Was fluctuating at 11/12 then hitting 15 with original diverter valve, so fitted n710. throttle response is now better, but I am only hitting 12 psi and no more.It will hit this level when floored in any gear, and just sit there, and it just doesent feel that quick ! Got a cheap vag com lead which showed 2 codes 16500 which was down to the faulty thermostat that I mentioned in a previous post, and 18010 which logs as "power supply terminal 30 voltage too low p1602", which I have know idea what that means.Anyway cleared the codes and went for a drive for 20 mins then re checked for the codes, which had not returned. Any ideas on the relativley low boost. I only have the shareware vagcom and am new to that so not quite sure what values/blocks to log and look for faults in. All input gratefully accepted.
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  3. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Feb 15, 2009]
    isnt it possible it was just mapped to that pressure?

    Power supply voltage is just that, means your battery voltage has been low at some point, either because the battery is a bit shonky, or that its been disconnected at some point.

    The only other possibility is the N75 valve being faulty. But the fact it quickly reaches 12psi then stays there would suggest thats what its mapped to.
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  4. turbonutterb
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    turbonutterb New Member

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    [Feb 15, 2009]
    Tuner says should be around 18psi. The battery had been disconnected, your bang on there.Hooked gauge up to turbo pipe b4 n75 to see what reading I got there, as opposed to from vacuum pipe, Only reading 10psi. Unhooked MAF plug, only 5psi and ran ****. Unhooked N75 and only 5psi as it should be on an open circuit.Is there a way to check the N75 and or Maf, or is it just a case of swapping them out ?Could a faulty lamda affect boost/fueling/SPEED....
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  5. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Feb 15, 2009]
    doubt the lambda could cause it tbh.

    Either the N75 itself is acting up, or the map is simply not requesting any more boost...
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  6. turbonutterb
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    turbonutterb New Member

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    [Feb 15, 2009]
    Is there a check for the N75 ?
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