R26 Misfire Under boost

Discussion in 'Mechanical - Engine, Gearbox, Exhaust etc' started by Zayd, Sep 14, 2022.

  1. Just when you think you know these cars, they never seize to surprise me lol.
    My R26 has developed a misfire under full boost. If I throttle lightly, she revs smoothly through thr rev range. The moment full boosts comes in, car feels like it's cutting spark.
    I've changed coils, changed and gapped plugs to 0.5, checked fuel pressure.
    Scanned with a CLIP. Knock sensor circuit error appears with an abnormal voltage fault. I've changed the knock sensor as well with no change.
    I'm absolutely stumped.
    Its worth mentioning that I can hear some air but I'm not convinced. It's difficult to check due to the fact that the issue is present only under full boost. Wondering if the actuator diaphragm is faulty. But yeah really don't know what to look at next. Any ideas?
     
  2. ianplymouth

    ianplymouth RSM Club Member

    I think we need a bit more information.......
    Is it mapped ???
    What fuel are you running ????
    What plugs do you have in the engine ????
    What miles is on the engine ????

    there are more questions depending on your answers
     
  3. Running a fully forged motor, 16T Turbo, bigger intercooler, 630cc injectors, Forge aactuator with red spring, Forge Recirc, DW65c fuel pump, 76mm downpipe, 63mm out from there. BKR7EIX iridium plugs gapped to 0.5.
    Using 95 pump fuel.
    Motor was recently rebuilt. About 1200km on it.

    Car was tuned for the setup and was running fine until last Saturday.
     
  4. ianplymouth

    ianplymouth RSM Club Member


    First i would swap the plugs for BKR8EIX and gap them to 0.6mm.
    The forge actuators aren't the best, the standard Renault ones are good, the 250 ones are better as they have a stronger spring, i am running this same setup bar the Actuator, i also have a 250 fuel rail and rising rate setup, this gave me 310hp and 360ftlb of torque.

    Can't really see why you have the problem, can you get 98+ fuel and try that.

    I had a customer with an outboard that had running issues, put super unleaded in and that cured the running problem.
     
  5. Thanks gentlemen. Just an update.
    I noticed that the knock sensor plug and oil sensor plug are swopped. Saw a black plug on thr knock sensor and looked back at old pictures of the motor. Defs should be a brown one on there. Will swop in the morning but I think that's the issue.
     
  6. ianplymouth

    ianplymouth RSM Club Member

    you didn't say that there had been work carried out that would need the plugs to be removed.

    The plugs won't swap themselves over :laughing::laughing::laughing:
     

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