ajay

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  • in reply to: Long Cranks only after engine off an hour or so #6419
    ajay
    Participant

      Resolved! Replacing the fuel injectors on both banks fixed this warm start long cranking problem. Thanks again for the advice here. Unfortunately I didn’t get a chance to test hot leak down with the new injectors installed but changing out the fuel injectors was the only modification made to the vehicle to fix. New o-rings and lower seals were used each time the injectors were moved with FSM fuel rail torquing so I figure that even if the injectors pass a cold leak down test there was a hot leak happening.

      in reply to: Long Cranks only after engine off an hour or so #5072
      ajay
      Participant

        An update further to Matt’s suggestion about checking static fuel pressure. I went ahead and checked leak down with a hot and cold engine on both fuel rails separately. The gauge went onto the short hose that feeds the rail with the hose upstream clamped so the only place fuel could escape would be through the injectors, hose or perhaps a leak in the gauge.

        When cold both banks dropped 5-10 psi after 90 minutes. With the engine hot bank 2 pressure dropped to zero and bank 1 by 20+ psi. Also noticed that with the clamps removed the engine started much better. So perhaps fuel was getting through the hot injectors somehow.

        I purchased and installed three new fuel injectors for bank 2, the long cranking situation is still present but consistently improved. I’ll grab another three injectors in the future when conditions permit and report back. Thanks again.

        in reply to: Long Cranks only after engine off an hour or so #4782
        ajay
        Participant

          It sure did ! 🙂

          I removed and replaced the injectors myself for the cleaning, was reasonably gentle on the car although not having done that before could have knocked something. Also you got me thinking again about the ECT sensor.

          Today waited 90 minutes after turning the engine off hot as this guarantees long cranking and saw the scan tool report coolant temperature at 60 degrees Celsius. Started the engine which struggled as expected and then waited until the temp got to 70C. Turned the engine off and waited until the coolant temp was back down at 60C to see what would happen cranking again. She started up fine so to be sure repeated that test several times with the same result.

          I’ll also try to use some fuel hose and a schrader t-connector to get the fuel pressure gauge inline with the feed for each bank of three injectors and clamp upstream to see if the pressure drops. And if the results are even for both banks. I guess there’d be no other place for gas to go than via the injectors.

          in reply to: Long Cranks only after engine off an hour or so #4749
          ajay
          Participant

            Hi, this is the first car i took a real interest in and doing my own maintenance. Had the injectors cleaned because the commute takes me past an injector cleaning company and eventually curiosity won over! The long cranking problem definitely started after the injectors were back in.

            Yes I have access to the engine computer parameters with the neat open source FreeSSM and RomRaider projects which run on a laptop computer and have scan tool and logging capability when connected to the cars OBD-II port.

            in reply to: Long Cranks only after engine off an hour or so #4692
            ajay
            Participant

              Took a look… with the engine off fuel pressure goes straight to 52psi steady when the computer runs the pump for 2 seconds after ignition on. After that it goes to 48psi until the engine is started and idling where it stays at 48psi. The factory service manual describes 48 to 52 psi, return less system with no FPR under the hood.

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