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Losing power at fuel pump

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  • Losing power at fuel pump

    So I have only found one thread on here that matches the issues I’m having but it was from 2014 and no resolution was posted. 2006 Four Winn’s H260 with a 5.7 GXi. I recently replaced my low pressure pump after tracking down the flaking paint issue within the Volvo Penta pump housing. Checked high and low pressure pumps on the hose and both were in recommended range. Dropped her in the lake the next day and began my slow speed increase accross the water just to see if I encountered any hesitation or misfire issues. Keep in mind prior to determining I had paint flakes in my pump housing and regulator I started with other items such as replacing ignition coil, distributor cap, rotor, and plugs. Also pulled my TB off and cleaned it up. Back to the throttle up. Boat ran smooth up through 3k RMPs. Once I got over 3k, engin shut off.

    Popped hatch and determined I wasn’t hearing my fuel pumps turn on. Started checking all the fuses, relays, power lines and harness. Nothing. Everything looked good and intact. All my grounds seems secure as well. Boat turned over but no fire. Checked coil wire And saw I was indeed getting a spark. Once I determined I was up a creek without a paddle I started swimming. Took me about 1.5 hours to drag this 26’ Hull to the shore where I planned to drop anchor and walk to my truck. Figured I would try one more time and just like that I had power back to pumps and engine started. Went straight to dock and back home but never throttled over 1500 when heading back to dock. Spent some time on hose at the house and never had an issue. Went back out today in an attempt to recreate the issue. As expected I crossed the 3k rpm threshold and same result... dead with no power to fuel pumps. Tooled around under hatch for about 30 minutes checking ECM connections and battery wires. Pulled coil wire off and the minute I went turn key on I hear the pumps prime! Starts up. Ran it again up to 3k to 3.5k rpms and it dies. I repeat this about 3 more times with same results.

    Next time I get it started I decided to throttle
    up in neutral and see if I get same result. Nothing at 3k. Ran it up to 4K and kept running. I then throttled
    up and down from idle to 4K a few times to see if I recreated the fault. It eventually died again with no apparent power to pump. This time I never got power back
    to pump. After about an hour I was able to get it started but noticed the pump never primed. I limped it back to dock on what I figure was residual fuel in the lines and loaded up. Back at home I have yet to get power back to pumps. I figured the common denominator was the new pump
    i replaced. So I swapped it back with old low pressure pump. Still now power.

    I have have checked all fuses, what I think are all the ground wires including alternator connections. It has got to be something within the ECM that’s detecting a problem and shutting off my fuel power but I’m out of ideas. Anyone come
    across the same issues and found a solution that didn’t involve purchasing a new ECM?

  • #2
    You have a GXi what (A-J)?
    94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
    95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
    07 Seadoo GTX
    Merc Adults Only VP Adults Only
    G-Dad always said "First Liar doesn't stand a chance"

    Comment


    • #3
      It’s a GXi-F

      Comment


      • #4
        I have also checked with a voltage meter and I’m not getting any power at the relay ports or F7 fuse.

        Comment


        • #5
          Originally posted by Hughes179 View Post
          I have also checked with a voltage meter and I’m not getting any power at the relay ports or F7 fuse.
          Don't have a F but have up to D model but with not power to the fuse, then either the fuse is blown or the Red feeding the fuses is disconnected

          Click image for larger version

Name:	gxi fuse.jpg
Views:	2
Size:	88.4 KB
ID:	10778076
          94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
          95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
          07 Seadoo GTX
          Merc Adults Only VP Adults Only
          G-Dad always said "First Liar doesn't stand a chance"

          Comment


          • #6
            Okay this diagram will definitely help me trace the power source. I’ll see what I come up with and follow up. Thanks.

            Comment


            • #7
              I had a similar issue. Ended up being the wiring to the kill switch

              Comment


              • #8
                So today I install a jumper wire between 30 and 87 leads at the fuel pump relay. Pump would turn on a run constantly. Swap the jumpers for the relay and nothing. The same results with the spare relay. Any idea what would cause that?

                Comment


                • #9
                  Jumping 30 and 87 bypasses the relay contacts and send power straight to the pump

                  Jumping pins 85 and 86 might blow the fuse because of applying a dead short. Pin 86 should have 12V power with key ON, and the ECM should apply a ground on pin 85 to energize the relay
                  94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
                  95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
                  07 Seadoo GTX
                  Merc Adults Only VP Adults Only
                  G-Dad always said "First Liar doesn't stand a chance"

                  Comment


                  • #10
                    Okay I’ll check voltage on 86 and see if I get anything. If not could that be signs of an ignition issue under dash vs engine compartment or worse a ECM?

                    Comment


                    • #11
                      So I determined I do have 12v at pin 86. Pumps will run when I run a jumper cable to everything except 85. It doesn’t seem the 85 pin is grounding as it should be. I have also replaced the egnition key assembly because it was looking pretty old and cooreded. Still no change. I came across a link on here from 2012 speaking of a service bulletin from Volvo Penta about a faulty fuse box assembly. Specifically regarding the fuel pumps intermittently working due to a defective circuit board within the fuse box. I am running out of ideas and this seems to be an option. At this point I’m ready to run a 12v line to my pumps that I can activate with a toggle switch at the dash. Below is a link to the faulty fuse box thread

                      https://forums.iboats.com/forum/engi...th-ignition-on

                      Comment


                      • #12
                        It doesn’t seem the 85 pin is grounding as it should be.
                        This is your problem, just need to know why its happening

                        When your cranking the motor, do you see at least 300 rpm on the tachometer?
                        94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
                        95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
                        07 Seadoo GTX
                        Merc Adults Only VP Adults Only
                        G-Dad always said "First Liar doesn't stand a chance"

                        Comment


                        • #13
                          Yes tach jumps to 300 at minimum

                          Comment


                          • #14
                            Not a jump but does it stay at 300 or so as long as motor is being cranked?
                            94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
                            95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
                            07 Seadoo GTX
                            Merc Adults Only VP Adults Only
                            G-Dad always said "First Liar doesn't stand a chance"

                            Comment


                            • #15
                              Sign up today
                              Yes it’s 300-350 as long as the engine is turning

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