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Question regarding TQS sensors

Discussion in 'A3/S3 Forum (8L Chassis)' started by sprushty, Apr 3, 2013.

  1. sprushty
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    sprushty TQS Collective

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    [Apr 3, 2013]
    I have a AJQ engine, how many lambda sensors does the TQS have? Also where is the intake air temperature sensor and Map sensor located? My car is giving me **** mpg, 100 miles to a half tank, no vag com errors either.
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  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Apr 3, 2013]
    I believe your car (99 tqs isn't it?) has one lambda... its narrow band and just past the flexi in the down pipe

    Intake air temp sensor is in the inlet manifold next to where the throttle body is bolted on

    Map sensor will be in the top of the SMIC located drivers side behind the bumper

    If you have no fault codes in VCDS then there is no point looking at these sensors as they generally don't go wrong (and if they did they would produce a fault code either directly or indirectly)... my money is on the CTS... check engine temp in VCDS as there are two sensors in the CTS, one for the ECU and one for the dash... not unusual for one to go and the dash to show normal temps while the ECU is still on cold start or warm up...

    Maybe worth doing a little logging, check the fuel trims in block 032... you can also check lambda voltages etc to see what idle and cruise are doing but as its narrow band you can't log WOT fuelling... also see what the airflow is like as a poorly MAF will affect MPG on narrow band cars

    <tuffty/>
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  4. sprushty
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    sprushty TQS Collective

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    [Apr 5, 2013]
    Tuffty, I changed the CTS about a month ago, new unit from ECP. I had to do a motorway run yesterday and the temp needle took a very long time to reach 90 then while running at 70~mph the needle would occasionally drop a little bit below 90 which I thought was odd, maybe the thermostat? I will do some VCDS logging soon and update this post, cheers.
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  5. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Apr 5, 2013]
    If you haven't changed the stat then its worth doing but tbh I would use an OE one... have also had issues with ECP sensors failing...

    <tuffty/>
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