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Thread: Overboost

  1. #1


    Hi, I am having problems with my R12x with Macsboost stage 2, H20 free flow exhaust, blow off valve, and electronic boost controller. Its runs fine until wot, I can run wot for about 5 seconds then code 45. I am getting 12 psi at around 6100 rpms, I've tried upping boost over 12.5 psi but throws code 45 once I get into wot, I can get it up to the rev limit but it will always throw the over boost code, and that would be only about 15 psi, it doesn't make since, I thought with the stage 2 I could run up to 19psi, replaced ecu last year and map sensors this year, checked vacuum hoses and everything, where should I look next.

  2. #2
    Join Date
    Jan 2008
    Currituck, North Carolina, United States
    Nope you will never see 19lb of boost best you will see is 15lb. ECU will limit manafold pressure and rpms.

  3. #3
    jlfx car audio's Avatar
    Join Date
    Jul 2011
    jackson, TN
    Of your running mac boost and it isnt allowing you to add more boost for extended time your probably heat soaking or getting spark knock and ecu is attempting to pull boost to get system in check and since your running mbc its throwing code 45..
    make sure your ic is getting good water flow and your running good gas. To avoid as many detination issues

  4. #4
    I use 91 octane, I know higher octane would be better but would that cause heat soak or knock, and how do I check good ic water flow.

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