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  1. #1
    Dirty Sanchez's Avatar
    Join Date
    Dec 2005
    Northern Virginia

    Riva injectors issue with rotax stock class ecu- anyone else have this??

    Guys- I have an rxt running and x charger, rr stock class 8500 ecu with 42lbs rotax injector RRFPR set 65 base A/F 12-12.5. This set up is running great 75-78 mph @ 8400 rpm'sdepending on conditions.

    I installed a rude charger with 48lbs injectors lost 6-700 rpms. Couldn't get the A/F below 13? MAX RPMS 7800 @ 70MPH

    I then tried a friends set 50lb riva injectors. Idled like dog crap. only 2 cylinder firing. Once off idle it pulled hard and obtained 8350 rpms unsure actual speed???

    I then tried Mitch's 60 lbs injector and Idled like crap but ran ok once off idle, but too rich

    I also tried a Les Cooke ecu flashed to work with 42lbs fuel mapping and an 8650 rev limiter

    Still no dice- all injectors combinations failed

    Question: what other injectors combo's are out there. Could my friends 50lbs injector have issue?? Causing my poor run conditions?

    Has any one else had funky performance issues with riva injectors with non riva ecu's??

    I put my rotax 42's, stock class ecu and x charger and everything is happy?? WTF?

  2. #2
    Site Admin Green Hulk's Avatar
    Join Date
    Apr 2005
    Morgan City, LA
    Chris, the problem is your 65 psi base pressure. None of those bigger injectors are going to idle worth a damn with that much base pressure. I would install the Walbro GSS342 fuel pump and then lower the base pressure. You have maxed out your stock fuel pump.

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