could a dodgy voltage reg stop car starting?

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  • avants2turbo
    S2Forum Extremist
    • Feb 2008
    • 1287
    • Country: England

    #1

    could a dodgy voltage reg stop car starting?

    Another non starter!

    Breif history-
    Car running fine only problem seemed to be dodgy voltage reg (lights going up and down on idle and with revs etc)

    Parked up one night, raining that night, went to start next day, tuned over, almost fired, then just turned over and over.
    Replaced the 2 crank sensors a few days later, it fired up. Drove the car to my workshop, then back again, parked up, next day same again! Tried almost to fire one then just turns over and over.

    Left it a couple of weeks with this crappy weather, tried to start it just now same again, almost fired once, then just turns over and over.

    Just done a blink test and only get 2111 (g28 i beleive) which i understand should come up if the engines not running?

    I dont think ive got a timing/crank keyway shere as it didnt work, then did then didnt and ran perfectly when ut was running (apart from the voltage fluctuations)
  • UrS4boy
    S2Forum Obsessed
    • Feb 2006
    • 11859
    • Country: Canada

    #2
    A non-running car will always throw a G28 engine speed fault code (because the engine is stopped). Your problem sounds like either a dead fuel pump or a bad Cam (Hall) sender.

    The only was the voltage regulator can cause non-starting is if the battery goes flat because of the dodgy VR. Your battery sounds fine(ish) since the starter is engaging and cranking the engine.
    RS2'd 93 UrS4 5 spd sedan
    94 UrS4 V8 6 spd manual avant

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    • pixsaudisex2
      S2Forum Possessed
      • Sep 2004
      • 3110

      #3
      Originally posted by UrS4boy
      A non-running car will always throw a G28 engine speed fault code (because the engine is stopped). Your problem sounds like either a dead fuel pump or a bad Cam (Hall) sender.

      The only was the voltage regulator can cause non-starting is if the battery goes flat because of the dodgy VR. Your battery sounds fine(ish) since the starter is engaging and cranking the engine.
      is this the pour water behind the cam cover to test the sensor..

      Comment

      • avants2turbo
        S2Forum Extremist
        • Feb 2008
        • 1287
        • Country: England

        #4
        Tried that, and different fuel pump relay, nothing, just got a pm with another idea to try

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        • Pirvu Eugen
          S2Forum Extremist
          • Apr 2007
          • 1978
          • Country: Romania

          #5
          you hear the pump?
          Short across the big 2 pins from fuel pump relay and listen for the pump.
          Maibe is blocked.
          Just a thought!

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          • avants2turbo
            S2Forum Extremist
            • Feb 2008
            • 1287
            • Country: England

            #6
            im sure ive read on here a million times that the fuel pump doesnt prime on the ABY?

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            • Pirvu Eugen
              S2Forum Extremist
              • Apr 2007
              • 1978
              • Country: Romania

              #7
              Is right...this is the reason i told you to short across the 2 big termials at the fuel pump relay.....In this way you give 12v at the pump direct....makes sense? So you can actualy listen for the pump..
              I have a small wire with 2 flat terminals to do this...

              Comment

              • pixsaudisex2
                S2Forum Possessed
                • Sep 2004
                • 3110

                #8
                undo the fuel pipes an see if it is under pressure i do... but be carefull not to bend the pipes...

                My fuel pump went like this a long time ago sure i could hear it just no power:mischeif:
                ( wouldnt start)

                Not caught a wire or anything... earth loose blar blar blar..

                Comment

                • Pirvu Eugen
                  S2Forum Extremist
                  • Apr 2007
                  • 1978
                  • Country: Romania

                  #9
                  Originally posted by pixsaudisex2
                  undo the fuel pipes an see if it is under pressure i do... but be carefull not to bend the pipes...

                  My fuel pump went like this a long time ago sure i could hear it just no power:mischeif:
                  ( wouldnt start)

                  Not caught a wire or anything... earth loose blar blar blar..
                  I agree! Is a posibility......

                  Comment

                  • avants2turbo
                    S2Forum Extremist
                    • Feb 2008
                    • 1287
                    • Country: England

                    #10
                    hmm, will give that a try, just spoken to chef and hes suggested some things aswell as he has worked on the car when i was with the previous owner..

                    the engine was removed recently to replace the clutch pressure plate, will have to go through everything to make sure its all in properly, i know all the earths are in place etc, the only thing that was slightly dodgy was the cam pos sensor plug (sensor plug not loom plug) did get crushed by a 3/8" extension bar which exposed the 3 wires, but i did tape them up best i could, surely if there was a problem with the cam pos sensor the blink codes would have indicated this?

                    Comment

                    • UrS4boy
                      S2Forum Obsessed
                      • Feb 2006
                      • 11859
                      • Country: Canada

                      #11
                      Originally posted by avants2turbo
                      ..the engine was removed recently to replace the clutch pressure plate, will have to go through everything to make sure its all in properly, i know all the earths are in place etc, the only thing that was slightly dodgy was the cam pos sensor plug (sensor plug not loom plug) did get crushed by a 3/8" extension bar which exposed the 3 wires, but i did tape them up best i could, surely if there was a problem with the cam pos sensor the blink codes would have indicated this?
                      1) There is no good reason to remove the engine *just* to replace the clutch pressure plate. None. You might have been $cammed. I would like to hear why the engine came out. It's not a B5 S4 afterall.

                      2) Poor Cam sensor connection = no start. Should throw a 2113 blink code but maybe not. Focus on that three pin connector. The female harness portion is 443906233. The male Cam sensor end is 443906247. There are VW three pin O2 sensors that use these equivalent connectors (but the pins might not come out and you might have to crimp wires)

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

                      Comment

                      • avants2turbo
                        S2Forum Extremist
                        • Feb 2008
                        • 1287
                        • Country: England

                        #12
                        Originally posted by UrS4boy
                        1) There is no good reason to remove the engine *just* to replace the clutch pressure plate. None. You might have been $cammed. I would like to hear why the engine came out. It's not a B5 S4 afterall.

                        2) Poor Cam sensor connection = no start. Should throw a 2113 blink code but maybe not. Focus on that three pin connector. The female harness portion is 443906233. The male Cam sensor end is 443906247. There are VW three pin O2 sensors that use these equivalent connectors (but the pins might not come out and you might have to crimp wires)

                        I wasnt scammed, i removed the engine to replace the pressure plate as its easier than removing the g/box, presumably the cam sensor from audi comes with the connector?

                        Comment

                        • johne
                          S2Forum Extremist
                          • Apr 2007
                          • 1404
                          • Country: United Kingdom

                          #13
                          Originally posted by avants2turbo
                          I wasnt scammed, i removed the engine to replace the pressure plate as its easier than removing the g/box, presumably the cam sensor from audi comes with the connector?
                          It does and the mounting bracket and costs around £140. You can buy just the sensor and mount it on your old bracket yourself. The sensors come from the US. I've a few on their way to me but they're stuck in the post somewhere

                          When they arrive they'll be around £20 including postage depending on how much duty I have to pay.

                          John

                          Comment

                          • UrS4boy
                            S2Forum Obsessed
                            • Feb 2006
                            • 11859
                            • Country: Canada

                            #14
                            Cam Position Sensor replacement info.

                            Originally posted by avants2turbo
                            I wasnt scammed, i removed the engine to replace the pressure plate as its easier than removing the g/box, presumably the cam sensor from audi comes with the connector?
                            Apparently you like to do things the hard way.

                            Good luck. You should also remove the engine to replace the cam sensor.

                            Way easier than this method:



                            Which is contained in this G40 Cam Position sender info post:

                            The Audi Enthusiast website. Forums for all Audis including A4, S4, A5, S5, A6, S6, allroad, A8, S8, TT, R8, Q5, Q7, 4000, 100, 200, v6, v8, vintage, local forums
                            RS2'd 93 UrS4 5 spd sedan
                            94 UrS4 V8 6 spd manual avant

                            Comment

                            • avants2turbo
                              S2Forum Extremist
                              • Feb 2008
                              • 1287
                              • Country: England

                              #15
                              Originally posted by johne
                              It does and the mounting bracket and costs around £140. You can buy just the sensor and mount it on your old bracket yourself. The sensors come from the US. I've a few on their way to me but they're stuck in the post somewhere

                              When they arrive they'll be around £20 including postage depending on how much duty I have to pay.

                              John
                              the ones youve ordered from the other side of the pond dont come with the connector though do they? you have to splice them into the origional connector? and its the origional connector I have managed to ****** up! or do they come with the connector?

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