Announcement

Collapse
No announcement yet.

Hesitating at full throttle ?

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • #61
    Why does pressure drop to 1 bar when it should be around 4 bar?

    Comment


    • #62
      A bit leftfield...... could there be an airlock? A trapped bubble that under certain conditions (heat, increased fuel flow) moves to a narrower section of pipe and obstructs flow and hence available pressure?

      Comment


      • #63
        Yes an airlock it must be!

        Comment


        • #64
          How airlock van happen ? What do you think about the hole at the cup ?

          Comment


          • #65
            Originally posted by marcjero View Post
            How airlock van happen ?
            When the fuel filter was changed, its volume of air would have been pumped through the system. You'd expect it be purged right out through the injectors but as the path to the injectors is downward possibly there is a pocket of air in the fuel rail obstructing fuel flow.
            If so (and I admit it is an outside chance that this has occurred) releasing a pipe on the fuel rail (given it is higher than the injectors) should allow escape of any air. I'd do that if only to eliminate it as a possibility.

            Comment


            • #66
              Air lock being the cause is as just wild as blaming pedal or valve rubber. Better trying to fathom out why rail pressure drops to 1 bar when engine misfires.

              Comment


              • #67
                I got the used pump from a 450 assembly. The assembly is a bit different so we had to move the 450 pump to the roadster assembly. The 450 assembly doesn't have any hole at the bottom. Knowing that the plastic bit that should block this hole is broken...

                Comment


                • #68
                  hi,

                  I tried to pinch the fuel return line when the pressure drops. It doesn't help restoring fuel pressure. So the problem is not related to fuel rail or fuel pressure regulator.

                  Next step is to check the fuel lines and the fuel filter.

                  Comment


                  • #69
                    Problem solved (it seems to be) !
                    Fuel filter was clogged. In fact we think that it was fitted the wrong way. So it didn't last a lot of miles.
                    Could you please confirm that the upper fuel line is the one coming from the tank ?
                    Really happy to find a rational reason for this mess. Please note that the filter was fitted the wrong way in a Mercedes shop. Shame on them !

                    Comment


                    • #70
                      I wonder why we did not think of that! As I recall fuel filter has an arrow on it indicating direction of flow. Why do you need to know which fuel line is which? Impossible to fit filter on return line as no quick connectors.

                      Comment


                      • #71
                        I don't care about the return line. At the filter area one fuel line is coming from the pump and another is going to the injectors rail. We found that the upper fuel line is the one coming from the pump. So the arrow on the filter should be top down. The old filter was fitted bottom up !
                        Last edited by marcjero; 09-11-17, 10:51 PM.

                        Comment


                        • #72
                          I canít see how it is possible to fit fuel filter wrong way as it only goes one way into its support cradle.

                          Comment


                          • #73
                            It's supposed to be impossible to fit stop/tail lamp bulbs wrong ..... but people do (I cant think what the fuel filter looks like)

                            Comment


                            • #74
                              Fuel filter looks exactly the same on both ends. So it can be fitted the wrong way definitely. And it was !

                              Comment


                              • #75
                                We are all human and screw up from time to time. Most likely fuel filter support cradle was broken. Not uncommon on Smarts serviced by dealer and garages. That’ís why I service all my own vehicles including sewing machines and garden machinery. Got an incredibly high reliability rate. Never any need to check the cars over before MOT except lights and check for broken springs.
                                Last edited by tolsen; 09-11-17, 11:17 PM.

                                Comment

                                Ad Widget

                                Collapse
                                Working...
                                X