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  • Passat engine pulsing

    Hey guys,
    My 2005 Passat TDI starting having a little issue. Often, if in gear, but stopped, the engine rpm starts to pulse a bit. Maybe a little faster than once a second. Its not huge, but you can see the tach twitch, and definitley feel it.. If I put it in neutral, it stops, if I move, I no longer notice it. It happens in both drive and reverse.

    Things I have done recently include an injector purge, popped off EGR to have a look at the intake, looks fairly clean. Disconnected the MAF to see if it effected the idle, but no. Fuel filter is new. Scanned, no codes.

    I had a funny pulsing issue when I first got my Malone tune, years ago. We logged some data, and found he has an EGR setting wrong, but it also caused a pulsing, so I was wondering if the EGR could be acting up. I was also thinking about what the effects of a failing tandem pump or lift pump would be... Short of that, wondering if it could be something bigger like a torque converter or something in the auto transmission.

    Anyways, just curios if anyone had some ideas as to what else I could check.

    Much appreciated, thanks all!
    Last edited by stefan; 11-06-2017, 10:14 PM.
    Stefan
    -> '19 Deep Black Pearl Alltrack
    -> '05 Urban Grey Passat Wagon TDI.
    -> Past rides: '14 Allroad, 06 Mazda5, '98 Jetta K2, '01 Jetta TDI, '91 Mazda B2200, '81 Toyota Cressida
    -> FutuRe Ride...??!

  • #2
    Re: Passat engine pulsing

    I tried to get a video tonight but it's not acting up enough to really see at the moment. Just for reference though, I found this on YouTube and this is what it looks/sounds like.

    https://m.youtube.com/watch?feature=...&v=B0FigoWoNp4
    Last edited by stefan; 11-06-2017, 09:49 PM.
    Stefan
    -> '19 Deep Black Pearl Alltrack
    -> '05 Urban Grey Passat Wagon TDI.
    -> Past rides: '14 Allroad, 06 Mazda5, '98 Jetta K2, '01 Jetta TDI, '91 Mazda B2200, '81 Toyota Cressida
    -> FutuRe Ride...??!

    Comment


    • #3
      Re: Passat engine pulsing

      Sounds like fueling to me as it only happens when you first start it and evens out after a bit?
      2001 Jetta TDI GL Silver
      Malone Tune stage 5+ ,VNT17-22Turbo, OMI, PP Race Pipe, PD 150 Intake, 2 1/2" Straight back exhaust, no mufflers, 2 1/2" downpipe straight no Cat, Race 520 Injectors, 11mm Fuel Pump, Lift Pump, EGR Delete mod,DC Stage IV Clutch, Michelin X-Ice 2's, 26 lb/s of boost alll day long, Smoking like a train!

      Comment


      • #4
        Re: Passat engine pulsing

        That video isn't my car. On my car it happens even when hot. Can pull up to a red light and it will start pulsing. When it's doing it, it is pretty consistent. I can sit for the length of a red light and it's pulsing the whole time. One post I read mentioned the lift pump. Wondering if that could make sense as the tandem pump isn't working as hard at low rpm, maybe lift pump is more critical at low rpm? Bit of a long shot.... Hah.
        Stefan
        -> '19 Deep Black Pearl Alltrack
        -> '05 Urban Grey Passat Wagon TDI.
        -> Past rides: '14 Allroad, 06 Mazda5, '98 Jetta K2, '01 Jetta TDI, '91 Mazda B2200, '81 Toyota Cressida
        -> FutuRe Ride...??!

        Comment


        • #5
          Re: Passat engine pulsing

          Might be a vacuum leak, did you test O2 sensor or CCV?

          Comment


          • #6
            Re: Passat engine pulsing

            I am planning to check vacuum lines with a mityvac this weekend. CCV is moving air I think. Not sure how to test the O2 sensor, but I will look in to it.
            Stefan
            -> '19 Deep Black Pearl Alltrack
            -> '05 Urban Grey Passat Wagon TDI.
            -> Past rides: '14 Allroad, 06 Mazda5, '98 Jetta K2, '01 Jetta TDI, '91 Mazda B2200, '81 Toyota Cressida
            -> FutuRe Ride...??!

            Comment


            • #7
              Re: Passat engine pulsing

              There doesn't seem to be any vacuum leaks, and vacuum pump is pulling a lot of vacuum. I also popped out anti shudder valve and egr and ran input tests on them to make sure they were moving ok, and they seem to be.
              Stefan
              -> '19 Deep Black Pearl Alltrack
              -> '05 Urban Grey Passat Wagon TDI.
              -> Past rides: '14 Allroad, 06 Mazda5, '98 Jetta K2, '01 Jetta TDI, '91 Mazda B2200, '81 Toyota Cressida
              -> FutuRe Ride...??!

              Comment


              • #8
                Re: Passat engine pulsing

                Oh, I wasn't sure how to test O2 sensor, but I had another one so I swapped it in but it didn't make a difference.
                Stefan
                -> '19 Deep Black Pearl Alltrack
                -> '05 Urban Grey Passat Wagon TDI.
                -> Past rides: '14 Allroad, 06 Mazda5, '98 Jetta K2, '01 Jetta TDI, '91 Mazda B2200, '81 Toyota Cressida
                -> FutuRe Ride...??!

                Comment


                • #9
                  Re: Passat engine pulsing

                  Check the engine and transmission mounts
                  Current Fleet
                  #ProjectICreate Jetta GLI32
                  2001 Cobra #88/3786
                  1989 Jetta Trophy 1 of 500
                  2004 Audi A2 FSI Colour Storm RHD
                  2015 B8.5 S4 Sepang/Technik/6MT/SD/AAD/CF

                  Motorsport Engineer

                  Comment


                  • #10
                    Re: Passat engine pulsing

                    I had time to check the main 2 mounts and they are good I believe. Engine doesn't move much with this pulsing either.
                    Stefan
                    -> '19 Deep Black Pearl Alltrack
                    -> '05 Urban Grey Passat Wagon TDI.
                    -> Past rides: '14 Allroad, 06 Mazda5, '98 Jetta K2, '01 Jetta TDI, '91 Mazda B2200, '81 Toyota Cressida
                    -> FutuRe Ride...??!

                    Comment


                    • #11
                      Re: Passat engine pulsing

                      Pulled return line off of tandem pump today and let it run in to a jar. Getting the appropriate 1.3L per minute. So not that...
                      Stefan
                      -> '19 Deep Black Pearl Alltrack
                      -> '05 Urban Grey Passat Wagon TDI.
                      -> Past rides: '14 Allroad, 06 Mazda5, '98 Jetta K2, '01 Jetta TDI, '91 Mazda B2200, '81 Toyota Cressida
                      -> FutuRe Ride...??!

                      Comment


                      • #12
                        Re: Passat engine pulsing

                        When you're stopped have you tried pulling it out of gear and leaving it in neutral and seeing if it continues? Maybe that will give you some insight as to whether its engine or transmission related?
                        2001 Jetta TDI GL Silver
                        Malone Tune stage 5+ ,VNT17-22Turbo, OMI, PP Race Pipe, PD 150 Intake, 2 1/2" Straight back exhaust, no mufflers, 2 1/2" downpipe straight no Cat, Race 520 Injectors, 11mm Fuel Pump, Lift Pump, EGR Delete mod,DC Stage IV Clutch, Michelin X-Ice 2's, 26 lb/s of boost alll day long, Smoking like a train!

                        Comment


                        • #13
                          Re: Passat engine pulsing

                          It levels out right away when in neutral.
                          Its not super consistent, or at least the severity isn't. Sometimes it is hardly noticeable. There were a few days there where it as consistently doing it quite badly. Yesterday I didn't notice it though, this morning, it is there ,but pretty faint. So a little strange... I don't really want to book it in if I can't make it happen all the time.
                          No other hiccups with transmission though, if that were the culprit. Shifts beautifully still.
                          Last edited by stefan; 11-15-2017, 09:20 AM.
                          Stefan
                          -> '19 Deep Black Pearl Alltrack
                          -> '05 Urban Grey Passat Wagon TDI.
                          -> Past rides: '14 Allroad, 06 Mazda5, '98 Jetta K2, '01 Jetta TDI, '91 Mazda B2200, '81 Toyota Cressida
                          -> FutuRe Ride...??!

                          Comment


                          • #14
                            Re: Passat engine pulsing

                            You could run a can of Diesel Purge straight through the injection pump.

                            Sounds like you may need to take it to a mechanic to diagnose though.
                            Last edited by witchcraftz; 11-15-2017, 12:10 PM.

                            Comment


                            • #15
                              Re: Passat engine pulsing

                              Originally posted by witchcraftz View Post
                              You could run a can of Diesel Purge straight through the injection pump.

                              Sounds like you may need to take it to a mechanic to diagnose though.
                              Yes, I have done this already. I have a little 'kit' with a jar, tubing and a little inline filter. I usually do it every year or so.
                              Last edited by stefan; 11-15-2017, 01:24 PM.
                              Stefan
                              -> '19 Deep Black Pearl Alltrack
                              -> '05 Urban Grey Passat Wagon TDI.
                              -> Past rides: '14 Allroad, 06 Mazda5, '98 Jetta K2, '01 Jetta TDI, '91 Mazda B2200, '81 Toyota Cressida
                              -> FutuRe Ride...??!

                              Comment

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