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Cooling + turbo question AAN Urs4

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  • Cooling + turbo question AAN Urs4

    Hello,

    recently buyed my first urs4. Car was standing stil for 5years so i dit a big maintenance. And i have 2 problems..

    I replaced the waterpump + 87c thermostat and 2 sensors (brown 3 pin)under the inlet manifold and one white on the back of engine.

    coolant temp gauge idle after 105-110c fan works.
    temp driving 100c.

    ecu same temp..


    boost : 1.9 bar reading on speedo meter but does not feel as 230hp... more like 180 or something.

    boostlines ok. Dv changed

    no faultcodes.


    all info welcome.

  • #2
    It sounds like you changed the MFTS sensor too that may be causing the issue, were the connections on it good?
    Greg

    S2Forum.com Administrator & Webmaster

    '93 Coupe with a few tweeks

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    • #3
      yes ive changed all the temp sensors.

      where all oem and wanted to change them to be sure after 25years.

      wires not checked but the fan turns on so i think there is nothing wrong with the wires? before the AC dit not work and after changing all sensors it works again.

      looked at the pin connections and there was nothing strange.

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      • #4
        If I remember correctly, the secondary fan is operated by the 2 pin switch in the coolant manifold, the same one which operates the after-run pump. Also, the MFTS does not interfere with boost on the UrS4, the white sensor in the back of the head does.

        If the thermostat is working fine, I'd turn to the viscous fan. The clutch dies with age and does not spin the primary fan properly.

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        • #5
          Tested the visco clutch.. and its death.. almost no resistance. 100c temp and was possible to stop it like it was nothing.

          orderd a new one and will see if the problem is solved.

          Comment


          • #6
            Pull the plug off the MFTS to check if that's limiting boost, although it sounds like the car is producing what it should. Mye you're just expecting too much from a heavy, old car?

            Make sure that the water system is fully bled and sealed, as air in the system and leaks cause the gauge to misread.
            Cheers'en, AndyC

            K24 Racing - K24R Products

            sigpic

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            • #7
              Originally posted by Doebie View Post
              boost : 1.9 bar reading on speedo meter but does not feel as 230hp... more like 180 or something.
              As a new UrS4/S6 owner, you need to be aware of the UrS Engine Bay Device Map. It used to be "live" but now it is "just" a diagram with over 50 pertinent links under it:

              The host server that held the live Engine Bay Device Map "died" and we haven't found a new host (yet)
              BUT we still have this (not live but the list of 50+ items and their hyperlinks is there below the diagram):

              http://forums.quattroworld.com/s4s6/msgs/22625.phtml

              Since the "1.9" bar on the trip computer display is absolute, i.e. only about 0.8 Bar relative boost, I am guessing that a hose between the intake manifold and the G71 MAP sensor has come undone.
              You need to read this:

              Moisture trap: http://forums.quattroworld.com/s4s6/msgs/20401.phtml

              And oh yeah, for an AAN, the MFTS has NOTHING to do with boost (unless it is very very hot out and you have the A/C on).

              F76 MFTS info: http://forums.quattroworld.com/s4s6/msgs/22584.phtml

              Hope that helps






              RS2'd 93 UrS4 5 spd sedan
              94 UrS4 V8 6 spd manual avant

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              • #8
                Originally posted by UrS4boy View Post

                As a new UrS4/S6 owner, you need to be aware of the UrS Engine Bay Device Map. It used to be "live" but now it is "just" a diagram with over 50 pertinent links under it:

                Hope that helps


                Thanks. appriciated

                On the moisture trap is everything oke.

                gonna disconnect the green vacum hose from ecu to moisture trap and test is with compressed air.
                Also gonna check all the vacuum lines again to be sure.

                maybe opening the ecu because i saw there is also a vacuum hose to the internal map sensor and looks like the same as my old tdi. It can also be damaged.

                what is the absolute and relative boost on stock/tuned stage 1 urs4

                is there nobody that converted it to external map?. I dit it on my old afn tdi with an external 3bar map and recalibration.




                Originally posted by Rusty View Post
                Mye you're just expecting too much from a heavy, old car?

                Maybe.. im driving a 200hp 480nm old tdi..

                Comment


                • #9
                  You need to read more of my links because the answer to your MAP sensor is there waiting for you:

                  http://www.efiexpress.com/catalog/pr...products_id=82

                  If your moisture trap connections are fine and MAP sensor hose is fine, then your issue is the Waste Gate Frequency Valve. Check that link out too.

                  RS2'd 93 UrS4 5 spd sedan
                  94 UrS4 V8 6 spd manual avant

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                  • #10
                    i mean external 3bar map.. not internal..

                    so al the vacuum hoses you can delete and just a 3bar map sensor from the 150hp PD tdi engines (golf 4 ARL).

                    first i wanted to fit a 3bar map from rs2.. but they are quite expensive.. so i deleted my original 250kpa bosch sensor (same as urs4). soldered 3 wires on the place where the map was added. pluged them into a 3bar external sensor on the IC traject and then recalibrated the ecu.


                    i will take time to read everything thanks

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                    • #11
                      Most of us use this 3Bar sensor which easily fits inside and uses the same drive voltage. You just need a 3Bar chipset.

                      This one on eBay, you can buy these for a few £/€

                      https://www.ebay.co.uk/itm/171641952067

                      Last edited by newsh; 13th October 2017, 09:12.

                      S2 Coupe 3B Project


                      Ur quattro restoration

                      S2 Avant

                      Boost is the new rock and roll!
                      sigpic

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                      • #12
                        Originally posted by Doebie View Post
                        i mean external 3bar map.. not internal..
                        I know you meant external not internal. Nobody does an external when you can do an internal virtually plug and play 3.0 bar for US$80.

                        You are making this more difficult than it needs to be.


                        RS2'd 93 UrS4 5 spd sedan
                        94 UrS4 V8 6 spd manual avant

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                        • #13
                          Originally posted by newsh View Post
                          Most of us use this 3Bar sensor which easily fits inside and uses the same drive voltage. You just need a 3Bar chipset (and bigger turbo and injectors)
                          You do NOT need bigger turbo or injectors to run a 3 Bar MAP sensor in a 3B, AAN or ABY. That is what MTM's Stage 1+ (270-280 hp) was all about. Just a chipset and a new MAP sensor and Bob's your faster uncle.

                          And Doebie: An AAN is not a diesel. The AAN ECU wants and needs boost pressure feed back via those green hardlines so it can decide how much boost to give you (above wastegate spring pressure)

                          The official factory Boost and Over Boost curves

                          Last edited by UrS4boy; 13th October 2017, 07:05.
                          RS2'd 93 UrS4 5 spd sedan
                          94 UrS4 V8 6 spd manual avant

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