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  • Another power loss question

    An "interesting" series of power losses on a road trip fairly far from home. It was a dark and moist night, ha! Doing my usual 75 MPH and I feel a loss of power. Very linear and smooth, just a drop in revs with my foot still in it. I make my way to the travel lane as I head toward the shoulder and low and behold it comes back to life. No acceleration issues, no brutal 100% fuel pump cut out no missing. It happens twice more on the way home and I find that lifting off the throttle allows the situation to go away. Best description is as if something where being sucked into the fuel (I'm assuming fuel as electrical seems fine) system then freed when I lift. AFAIK, both fuel pumps are original on 150k car. Fuel filter is 7k old, pressure regulator and surge regulator are probably 25k miles old. Any ideas welcome.

    81 Ur Quattro
    87 911 M491 Cab
    89 M3
    89 944 T

    What can I say,
    I love wide fenders!

  • #2
    Any new rattles? My Cat's seem to be loose and seem to be strangling the engine. Just heard them rattling tonight so it's time to gut them.
    Who knows where I'll be, changes from day to Continent.

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    • #3
      yeah have a look at your cat. This sounds like a exhaust issue with a partially obstructed cat converter.
      --------------------------------------
      The God's chariot... (OO==[][]==OO)
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      • #4
        I had this exact issue, my power loss was accompanied by a strong wash of unburnt gasoline smell through the firewall. My cats were rattling loudly, I replaced them and the issue has not resurfaced. No idea if it was the cats.

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        • #5
          Originally posted by M-technik-3 View Post
          Any new rattles? My Cat's seem to be loose and seem to be strangling the engine. Just heard them rattling tonight so it's time to gut them.
          Well, that's 3 for checking out the cats, something I would have never thought of. I will be under the car to day to check it out, though I must say no rattles in that area that I know of. Any preferred way of checking other than for obvious rattles of the guts coming apart?

          81 Ur Quattro
          87 911 M491 Cab
          89 M3
          89 944 T

          What can I say,
          I love wide fenders!

          Comment


          • #6
            could also be a fuel supply issue: 0.75liters coming from the return in 30 sec is the required amount.

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            • #7
              Originally posted by hardtailer View Post
              could also be a fuel supply issue: 0.75liters coming from the return in 30 sec is the required amount.
              New data point, as I lay under the car thinking how much of a PITA it will be to change to external pump without a lift, I decide to check the condition of the internal pump as well. I notice the "ground foot" to the mounting cover looks like it has spent the cars life outside thopugh everything else looks fine. I have trouble getting continuity from the pump negative lead and the "grounding foot". Needs a lot of scraping. Barely able to get continuity from the negative lead to the rest of the cover. So I throw 12V straight at the pump and cricket sounds (nothing). keep the pump disconnected and try to start the car. It starts and idles fine. I didn't chance a drive but I'm thinking bad lift pump for starters.

              81 Ur Quattro
              87 911 M491 Cab
              89 M3
              89 944 T

              What can I say,
              I love wide fenders!

              Comment


              • #8
                If your lifter pump is dead, the car will run, it will just lean out at higher rpms and feel like you hit a headwind every few seconds.

                Speaking from experience.

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                • #9
                  Well replaced the in tank pump and it was date marked 10/88 so original. Now I have a nice little noticeable hum from the back seat that I have never had during my ownership! Now for a very long ride to see if that fixed my issues.

                  81 Ur Quattro
                  87 911 M491 Cab
                  89 M3
                  89 944 T

                  What can I say,
                  I love wide fenders!

                  Comment

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