R33 gtst rb25det not reving past 5500

Thread in 'Technical Questions' started by Lewis Dennison, Apr 23, 2019.

  1. Lewis Dennison

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    Hello there my r33 does go past 5500 revs when driving, in neutral it’s fine, also idles a bit crap drops then picks up then drops sometimes stalls

    Any ideas

    Thanks
     
  2. BenRice

    BenRice Well-Known Member

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    Check your intercooler piping. I bet one has popped off and the pipe is just sitting against the joiner

    If not, check all intercooler joiners for holes or tears

    Post again with the outcome!
     
  3. Lewis Dennison

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    Thanks bud I’ll check it tomorrow and post the outcome
     
  4. Lewis Dennison

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    Also it sometimes isles low and stalls, it’s got new plugs and split fire coil pack, cleaned the idle valve, maf is clean also
     
  5. BenRice

    BenRice Well-Known Member

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    Also a symptom of a boost leak, however that could be a result of a bad AFM

    Does unplugging the AFM result in it idling?
     
  6. Lewis Dennison

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    The car cuts out when the maf is unplugged
     
  7. Lewis Dennison

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    All intercooler piping is fine
     
  8. Lewis Dennison

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    All intercooler piping/bends are fine
     
  9. orange_beastie

    orange_beastie Pickup driftin

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    Could be your fuel pump? Are all the connections good and earths ect?
     
  10. Lewis Dennison

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    I’ve ordered a walbro 255 so will change it when that comes
     
  11. BenRice

    BenRice Well-Known Member

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    Ok. Fuel is definitely the next on the list, however if you haven't changed your fuel filter recently do this before fitting your new fuel pump

    Next could be voltage drop due to old wiring so you'll need to look at hard wiring the fuel pump - run a 30A fused 10-12GA wire from the battery to the fuel pump via a relay, using the existing power feed as the switched positive feed for the relay.

    Final thing could be faulty knock sensors causing the ECU to limit the engine prematurely
     
  12. Lewis Dennison

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    Just got a new fuel filter and walbro 255 fuel pump which is going on in the week failing that I’ll try the wiring and get back to you. Have been told it’s the ecu so have ordered a z28 ecu and getting it mapped
     
  13. BenRice

    BenRice Well-Known Member

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    Who told you it's the ECU? Sounds like someone with a vested interest in a retune to me...
     
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  14. BenRice

    BenRice Well-Known Member

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    I'm not knocking getting a different ECU if it's something you'd like to do anyway, the factory unit is an utter pile of shit. If it senses the AFM maxing out, or too much knock it'll rich & retard the engine. Feels kind of like a limiter, but more like the engine is dropping an epic fart.

    That being said, your problem could be related to that. Like i mentioned previously a faulty knock sensor or AFM signal could be causing the rich & retard cut with load on the engine. Could also mean the engine is knocking...

    But getting a new ECU is not a fault diagnosis, especially when the recommendation is to upgrade it.
     
  15. smokebillowing

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    I know it sounds stupid, but check all fuses. My RB25DET did this once and it was the 'Engine control fuse'... Seriously.
     
  16. Lewis Dennison

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    Yeah that’s exactly what it’s doing, the engine sounds really nice no noises, may look into getting a new afm and sensor
     
  17. Lewis Dennison

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    Yes I’ll check them all and see what I can find thanks mate I’ll let you know once I’ve checked
     
  18. Lewis Dennison

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    Also should I get a standard rb25 r33 afm or go for the z32 afm
     
  19. smokebillowing

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    I also happen to have a stock R33 green label MAF for sale cheap if you want it.

    Z32 one will need a tweak to the map.
     
  20. Lewis Dennison

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    Message me mate could buy today
     

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