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2.0 TBI noise

Discussion in 'FAST Support Forum' started by crash520, Dec 31, 2017.

  1. crash520

    crash520 Member

    Joined:
    Dec 16, 2016
    Ok guys, I’ve asked Brian and Rich, now it’s ya’lls turn, I’ve installed XFI SPORTSMAN 2.0 TBI on my stock smallblock Mopar with a torker manifold, return fuel line, FAST Dual Sync, the install went well and she started up and runs great, I had to open the primary throttle blade a little to bring the IAC down to around 8-10 at idle.
    Now out cruising, taking off from lights and so on is great, crisp response, maybe a rare burble out of the exhaust on deceleration however, on acceleration to say change lanes or push up a hill etc, not WOT, I have this very loud chirping/cicada noise that comes in and out rapidly, anyone else had this??? Timing according to the log goes no higher than 34* and it’s certainly doesn’t sound like the normal pinging of detonation, any clues??
     
  2. crash520

    crash520 Member

    Joined:
    Dec 16, 2016
  3. crash520

    crash520 Member

    Joined:
    Dec 16, 2016
    Problem solved, it was the alternator, a new Tiff Stuff 100amp (actually it’s tested at only 74A), making that funky noise inside.
    I put the old alternator back on it which I think is a 55A unit and no noise at all. I’m not running electric fans or stereo or anything other than the ECU, the fuel pump and the CDI, and standard headlights so it might do for now
     
  4. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    You probably didn't have the belt on the higher output alternator tightened enough. Higher output alternators create more drag. Correctly tighten the belt until the alternator pulley nut can be used to turn the engine crankshaft. If that doesn't solve the problem, there may be a bad bearing in the Tuff Stuff alternator.
     
    crash520 likes this.
  5. crash520

    crash520 Member

    Joined:
    Dec 16, 2016
    AA, well, I spent a lot of time today correctly aligning the pulley, installed a new belt and had it so *Banned**Banned**Banned**Banned* tight I couldn’t get deflection, no belt slip at all and yes I could turn the engine over using the alternator, no change in noise and at idle there is a whine coming from the alternator, bearings are perfect, I’m starting to wonder now if it’s a rectifier noise, maybe a bad diode or something, the voltage trace on my log doesn’t show a nice flat line with minor changes in voltage, it’s very ‘noisy’
     
  6. Fastmanefi

    Fastmanefi Active Member

    Joined:
    Jun 4, 2011
    Location:
    Sonora, CA
    Replace the alternator.
     
  7. crash520

    crash520 Member

    Joined:
    Dec 16, 2016
    Working on that now Rich,
     
  8. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Yes, like Richard said. It's a bad alternator. Hope there is a warranty on the Tuff Stuff alternator you can take advantage of.
     
  9. crash520

    crash520 Member

    Joined:
    Dec 16, 2016
    Yeah I bought it off a guy, was brand new, no warranty, I’ll get a rectifier kit for it, I actually have a new 1990 Dakota 130A Denso unit to install, just making the bracket now for it, that should fix it, thanks guys
     
  10. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Have it checked for bad windings before you get the kit. No sense getting the kits if any windings are bad.
     
  11. crash520

    crash520 Member

    Joined:
    Dec 16, 2016
    Will have it checked later this week, had it checked before I installed it, it was a new unit not previously run, advertised as a 100A unit, came back from test 74A max, 14.7v
     
  12. crash520

    crash520 Member

    Joined:
    Dec 16, 2016
    Ok, well the Dakota Alternator is fitted and nice and quiet AND has 14.6 volts at idlewin win
     
  13. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    There you go! :cool:
     

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