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2.5TDi AEL pump timing problems

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  • 2.5TDi AEL pump timing problems

    Had to do the cambelt and fuel pump belt on my A6 2.5TDi the other day and now I can’t get the car running right again. Bear in mind it did run perfectly and started on the first touch of the key, even in the middle of winter before!
    Here’s what I did
    1.Engine was set to TDC on no.1 using the mark on the flywheel and verified with a welding rod down the glowplug hole.
    2.Cam locking tool installed and new cambelt, waterpump, tensioner and crank pulley installed, everthing tightend and tensioned and the engine spun over. Back at TDC the cam locking tool went back in.
    3.Fuel pump marks lined up and belt replaced and tensioned. Engine spun over and all marks lined back up.

    Now at this stage you need to get the engine up to temp and fine tune the pump yiming with VCDS, but mine runs like s**t! It takes an age to start and then smokes heavily. I did manage to get it up to temp but when I switch to ‘basic settings’ in VCDS, the engine immediately stalls. If I keep it revving, I can get a look at the timing graph and it’s showing that it’s really retarded, as in off the bottom of the scale, but my fuel pump will not advance far enough to get it back in range.

    I’ve double checked everything is lined up correctly a couple of times and everything looks good. I must be missing something, any ides what??

    sigpic
    1991 Audi S2 3B - 2.5 Stroker engine
    1997 A6 2.5TDi quattro avant - C4
    1976 RD250E / 350LC cafe racer

  • #2
    I had a similar problem with my wife's Passat. The locking tool used was an aftermarket one and the pump timing was out slightly. I ended up getting my Vag mechanic friend to use his proper vag tool and it was all fixed. What locking tool are you using?
    Nothelle S2 Avant in restoration
    Wr Ur Quattro (also in restoration)

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    • #3
      And maybe this will help
      https://www.vwt4forum.co.uk/archive/.../t-435866.html
      Nothelle S2 Avant in restoration
      Wr Ur Quattro (also in restoration)

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      • #4
        The only locking tool there is, is for the camshaft, and thats just a piece of flat bar that locks it paralell to the cam cover surface, you put feeler gauges under each side to shim it up.
        sigpic
        1991 Audi S2 3B - 2.5 Stroker engine
        1997 A6 2.5TDi quattro avant - C4
        1976 RD250E / 350LC cafe racer

        Comment


        • #5
          Originally posted by Tractor Dave View Post
          I think I've read every post on pump timing this week! I was going to try advancing the pump by a tooth on the belt, but it wasn't like this before and it ran perfectly?
          sigpic
          1991 Audi S2 3B - 2.5 Stroker engine
          1997 A6 2.5TDi quattro avant - C4
          1976 RD250E / 350LC cafe racer

          Comment


          • #6
            Ok, this was a few years ago and the car is long sold but I’m sure my vag guy had something which locked the pump timing as well. She now has a 4pot diesel which is a bit more simple!


            Sent from my iPhone using Tapatalk
            Nothelle S2 Avant in restoration
            Wr Ur Quattro (also in restoration)

            Comment


            • #7
              Of course not the right way, but the timing can be set very well without VCDS, just have to move the timing like 1mm and try it out. I had a Volvo with the same AEL engine. Bought it with a snapped timing belt, broken cam and a couple of bend valves, so had to take the head off. Had no locking tools and no program to check the fuel pump timing. First I had the pump in 180 degree wrong posititon, but swapped it over and the car tried to fire so it was close. Moved timing, tested, moved again, tested, now started up. Did go for a drive, worked fine, maybe little bit sluggish.. and cold start was quite long, so moved the timing a tad more, and now perfect start and power and almost no smoke.

              The area where the pump works is just a couple of mm, so it's needed to adjust in very small steps.

              Audi UrS4 Avant 2.5 20vt - twincharged - Project
              Audi 80q B4 Sedan 2.2 20vt - Daily user
              BMW 320d Touring e91 M-Sport - Daily user
              BMW 740iA e38 - Project

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              • #8
                I get this regular on t4s and end up helping lots of garages. Set the engine to tdc. Mark with tippex a r

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                • #9
                  Reference mark on pump pulley to cam cover. Loosen the pulley keeping the cam timing set. Advance the timing and re tighten the pulley. See how she starts and check with vcds. They are frustrating but once you get used to the tiny movements required to advance and retard you'll get there. The reference tippex mark is the best way I have learned to get a basic setting before fine tweaking on vcds.

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                  • #10
                    Originally posted by Monkeymagic View Post
                    Reference mark on pump pulley to cam cover. Loosen the pulley keeping the cam timing set. Advance the timing and re tighten the pulley. See how she starts and check with vcds. They are frustrating but once you get used to the tiny movements required to advance and retard you'll get there. The reference tippex mark is the best way I have learned to get a basic setting before fine tweaking on vcds.
                    Thanks, if it ever stops raining, I'll give that a try.
                    sigpic
                    1991 Audi S2 3B - 2.5 Stroker engine
                    1997 A6 2.5TDi quattro avant - C4
                    1976 RD250E / 350LC cafe racer

                    Comment


                    • #11
                      With the reference point on the cam pulley it saves keep trying so see the pump marks which never seems to line up. I alway dial in a bit of advance to begin with. You can normally feel the resistance on the pump pulley when you are in the right window.

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                      • #12
                        Andy,
                        If you set the pump up correctly statically following the factory procedure with a few tools, then it will be spot on! Assuming that the engine TDC is also correct and you have the correct A6 pump belt (80 tooth?).
                        I think you have the correct 3303 tensioner. You'll need a dial gauge adaptor for the pump. a dial gauge and some means of rotating the camshaft pump pulley and counterholding it during tightening.
                        That way its all set up from scratch and you don't have to make any more marks anywhere!
                        I'll try and send the info I have cobbled together via PM or alternatively PM me your email.

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                        • #13
                          Andy, PM me wih email!

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                          • #14
                            Only issue uve had with t4 is that the cam that drives dial gauge can wear meaning the readings are all wrong.
                            I prefer the vcds way. I'm not familiar with bethe tensioners on this engine but assume one is a roller that has a reference mark to the cylinder head and the other is a tensioner with a pointer?
                            Despite locking the fuel pump I've yet to do a cambekt on t4 then never had to mess with pump timing after. But will confess to not being familiar with this engine.

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                            • #15
                              I've done this a couple of times before and always got it close enough using the marks that I could fine tune it with VCDS, this time it just seems like something is out.
                              sigpic
                              1991 Audi S2 3B - 2.5 Stroker engine
                              1997 A6 2.5TDi quattro avant - C4
                              1976 RD250E / 350LC cafe racer

                              Comment

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