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1.8tqs project help needed

Chrisp_1 Jan 7, 2018

  1. Chrisp_1

    Chrisp_1 Registered User

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    Hello folks,
    bought my TQS from a friend last year, so far its had:
    - full Mehle suspension arm kit.
    - new suspension springs.
    - new cambelt and water pump.
    - full service oil, sparks, gearbox and diff oil.
    - dash pod repair due to pixelation.

    The car has been running sweet since March 2017 but not left my drive. Recently let the battery go flat and after charging it started fine but lumpy and cutting out.

    I noticed the vacuum hose running across front of the engine from manifold to PCV? (next to turbo) was taped up - I did this to get it to run when I first got it - so I've replaced that with new pipe/clips and also the small one from manifold to fuel rail. I'd also noticed the air box had been butchered in the process so replaced and rebuilt that including a 2nd hand purge valve (directly behind air box) as that was split too. This was all complete yesterday. When I started her up, she ran fine then died after about 5 minutes and then became progressively more difficult to start/run.

    Today I've had throttle body off, done a proper job including cleaning the temp sensor and inlet pipe. Started beautifully and ran for 10 mins then died.

    If I leave her for a while and disconnect battery then allow throttle body to adjust before starting she starts fine but after a while struggles and dies (runs for longer the longer I leave her sat).

    I'm thinking I may have a fuel pressure issue,.. anyone else got any ideas?

    I'm not sure if I had the fuel filter done with all the other jobs, I'm guessing that's next but without a code reader, and being SORN) I'm a bit stuck. Help me please.
     
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  3. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    I think you need to go and actually drive it. Messing about idling a car for hours on a driveway is not good for it.

    It might be a coolant sensor issue if it dies once it warms up. I've also seen crank sensors fail when they get hot. Not convinced its a fuel issue.

    You also NEED a fault code reader. These cars dont have an engine management light, so it might well be telling you exactly whats wrong with it, but without a fault code reader you cant see it. Buy the cheap VCDS lead off ebay for a tenner, and use the freeware software to get started.
     
  4. Chrisp_1

    Chrisp_1 Registered User

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    Thanks for response, I'm not sure it is 100% temp related as once it starts to struggle it needs to be reset by disconnecting battery before it will run normally, albeit temporarily.
    I'd like to drive it but its not insured/taxed and its not running well enough now lol. I was hoping to get winter out of the way before fitting new wheels.
    I agree on the code reader, only reason I haven't invested is lack of time to investigate WHAT to buy.
    Can you provide a link to your suggestion please Aragorn.
     
  5. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    ok so given what you've said, and guessing based on limited info, what might be happening is that the lambda is giving incorrect readings.

    The ECU has something called fuel trims, it monitors the fuel mixture using the lambda sensor, and adjusts the fuelling based on what the lambda says. If the lambda says "rich" it will lean out the mixture, and if it says "lean" it will richen the mixture. These values are over time "saved" to the ECU, so it compensates for slight differences in different engines and fuel systems etc.

    Various faults can cause the lambda to read incorrectly. The lambda itself might fail, or and exhaust leak might be present which lets excess air into the downpipe. The ECU then acts on these false readings, richening or leaning out the mixture trying to correct them. Eventually it can get so rich or so lean that the engine simply wont run.

    Removing the battery (i think) resets those fuel trims back to zero, and so you start again from scratch.

    Bad or failing MAF sensors can also cause similar issues.

    Diagnostics will let you read out the fuel trims and see if they are showing excessive adjustment.

    VCDS lead looks something like this:

    http://www.ebay.co.uk/itm/USB-OBD2-...555255?hash=item25dc48e737:g:MpgAAOSwOt9ZfKJa

    There are many vendors all largely selling the same thing. You can then download VCDS-Lite from RossTech and use it to connect to your car.
     
  6. Chrisp_1

    Chrisp_1 Registered User

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    Thanks Aragorn. I've ordered that cable, hopefully you chose wisely. I wish I had an old laptop to use for the software, will have to use my new one - can you run VCDS lite through any set-up, I remember in the days folks used to recommend a laptop with no other programs installed?

    Interesting thoughts on lamda sensor, I sort of ruled out MAF as I haven't changed it but might be worth trying with it unplugged as I think they revert to factory map? What you think?
     
  7. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    yeh i use it on my windows 10 laptop just fine.

    Unplugging MAF might help, but might not actually be the fault. Without the MAF the ECU will drop into a safe mode and likely switch off fuel trims. So if it were another fault, it might mask it.

    I would maybe try unplugging the lambda sensor, then the ECU will just stay running with the default settings.
     
  8. Chrisp_1

    Chrisp_1 Registered User

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    I'm glad I left the undertray off, definitely worth some unplugging as might rule out the fuel supply issue that's been bugging me (if it runs without the sensors that is). hopefully won't take long to get VCDS operational. could do with a local experienced user to give me a tutorial lol.
     
  9. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    lambda is accessible from above, its plugged in at the bulkhead behind the coolant bottle.
     
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  10. Chrisp_1

    Chrisp_1 Registered User

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    there are three connectors side by side from memory? I'm sure I'll be able to follow the lead from from exhaust to the correct one. Do you need to lift or remove the expansion tank from your experience? Not an issue just curious.
     
  11. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    yeh just unscrew the bottle and move it forwards, no need to disconnect the pipes. The lambda is the biggest connector, there are three smaller ones which are crank and knock sensors, then a big one for the lambda. The sensor is clearly visible in front of the cat, just beside the airbox, so you can easily follow the cable.
     
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  13. Chrisp_1

    Chrisp_1 Registered User

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    Well the cable just arrived but it's fouling the ashtray lid when I try to get it in the port FFS,.. is there an easy way to remove ashtrays lid (before I break it off in rage) as it should be good to go if I can, why they make it so tight back there is beyond me, it's a pretty standard connector!
     
  14. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    the ashtray just pulls out, with the lid attached. just pull straight up.
     
  15. Chrisp_1

    Chrisp_1 Registered User

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    sweet so it does, took a good tug mind. I also need to trim the tab on the connector, nothing straightforward! I shall have a poke at the cable after work (I work at home on Fridays if your wondering). No doubt I will have questions tomorrow when i've downloaded the software.
    thanks for sharing a of the above you are a real gent.
     
  16. Chrisp_1

    Chrisp_1 Registered User

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    OK so I got absolutely hammered last night and spent most of the day half asleep. Eventually I did manage to get out and got VCDS Lite up and running,.. it's definitely gonna needs some 'playing' with to figure out everything Lol.

    I've scanned most of the modules I can talk too and written down the fault-codes (see below), before clearing them. Tomorrow I'm going to fire her up (hopefully) and see what happens before scanning again, I didn't look into the details of when each fault was recorded (I see you can do this somewhere) so want to be sure everything is 'current'. Here is what my scans came up with:

    01 - Engine:
    00561 Mixture Adaptation (MAF, Fuel Pressure, Intake/exhaust leak, injectors)
    16500 P0116 Engine coolant temperature sensor (G62) implausible signal (wiring or sensor)
    16716 p0332 Knock sensor 2 (G66) too low (short/open circuit, improperly torqued, damaged senor or module)
    16711 p0327 Knock sensor 1 (G61) too low (short/open circuit, improperly torqued, damaged senor or module)
    16486 P0102MAF sensor (G70) too low (wiring or sensor)

    02 - AUTO-TRANS (not present)

    03 - ABS (No faults)

    08 HVAC (comms error)???

    09 CENT.ELEC. (No response)

    15 AIRBAGS (skipped that one)

    16 STEERING WHEEL (skipped that one)

    17 INSTRUMENTS:
    00771 Fuel level sensor open or short to plus
    00128 cannot find this code???
    01176 Key fob battery low
    00779 Outside air temperature sensor open or short to plus

    18 AUX. HEATING (no response)

    19 CAN GATEWAY (no response)

    22 AWD (no response)

    25 IMMOBILISER (No faults)

    35 CENTRAL LOCKS (9 alarm events or various kinds)

    37 NAVIGATION (no response)

    45 INTERIOR MONITOR (no faults)

    46 CENTRAL CONV. (no response)

    55 XENONS (no response)

    56 RADIO (no response)


    Any thoughts on the above? It seems most guesses above were 'on-target'. I could really do with working out if one or more sensor error could be causing the other but then again I need to see what comes back tomorrow (I will try and learn how to copy the scan results into notepad tomorrow).

    Also, would you recommend 'registering' VCDS lite, now I'm up and running, as I wanted to do a throttle adaptation but noticed its locked on shareware version. My car definitely doe the self adaption with ignition on, but despite starting smooth after first time I did it still stalled after 5 min.

    Cheers
    Chris
     
  17. Andy avant b5

    Andy avant b5 Registered User

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    I am thinking of getting one of these less as well all I have is a obd reader but not that good
     
  18. Chrisp_1

    Chrisp_1 Registered User

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    for the money it is a no brainer, although you do need to file off the edge of 'tab' on the one linked above,.. also I'd download VCDS direct from Ross-Tech. I will probably go registered and maybe even upgrade to a genuine cable eventually.
     
  19. Andy avant b5

    Andy avant b5 Registered User

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    Did you buy the one on the link
     
  20. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    Were all the codes active or flagged as intermittent?

    "intermittent" means the code was there, but isnt any more.

    Best thing is to clear the codes, then fire it up again and see which codes return.
     
  21. Chrisp_1

    Chrisp_1 Registered User

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    yes mate,.. came in 2-days too. I just used a fine file to take 1mm from each ide of the tab.
     
  22. Andy avant b5

    Andy avant b5 Registered User

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    OK cool thanks
     
  23. Chrisp_1

    Chrisp_1 Registered User

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    that's the plan for the morning,.. left it too late starting today due to the hangover ;-)

    I will jopefully have a better attention span tomorrow as I don't recall seeing any active/intermittent flags lol.
     
  24. Andy avant b5

    Andy avant b5 Registered User

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    Let me know how it goes a tomorrow interested in doing this to mine
     
  25. Chrisp_1

    Chrisp_1 Registered User

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    Ok so I've started the car this morning after clearing all codes yesterday. Starts, runs for a few seconds then dies. Tried it 3 times same difference.

    Plug in VCDS and do auto-scan, no fault codes. How bizarre.

    DO I NEED TO GET REGISTERED ON ROSS-Tech and do throttle adaptation to be sure it's not that (following recent dead battery)?

    Just to confirm my car does make the noise from the throttle body with ignition on door/open as described above, what is this doing if not 'adapting'?
     
  26. Chrisp_1

    Chrisp_1 Registered User

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    ok so I've had a unplug and try session finally,..

    disconnected the MAF and bingo, running outside now. hopefully it will stay running so I can get upto temperature - update, confirmed upto temp, turns on/off no problems. I guess I need a new MAF, have one from an A6 lying round so gonna try that although slightly different part number from memory.

    Still interested in your thought on 'adaptation' questions above. Cheers.
     
    Last edited: Jan 14, 2018
  27. Andy avant b5

    Andy avant b5 Registered User

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    I've ordered one of them cables just need to find my laptop lol
     
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  28. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    part number of the maf needs to match exactly
     
  29. Andy avant b5

    Andy avant b5 Registered User

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    Hi have got the cable today and a disc what's the next step to do
     
  30. Chrisp_1

    Chrisp_1 Registered User

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    sorry. swapped phones hence no notifications!
    Download software from ross-tech
    http://www.ross-tech.com/vcds-lite/download/index.php

    insert disk and download driver.

    prep cable (file tab edges) to get it to fit socket as required.

    connect laptop to car with cable open software and test. needs to be com port 1 to 4. if not change setting on device manager.

    once connection has been verified you can run auto-scan. ignore the register message and select copy to paste into notepad.

    good luck
     

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