knowledgeable peeps please....

Discussion in 'Flight Following' started by eman1200, Dec 6, 2017.

  1. eman1200

    eman1200 Final Approach

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    I don't use any of those gauge thingies since my instructor told me to always look outside.

    so I bring a safety pilot along with me every flight so they can look at those thingies and it's typically pretty stable between 20-25, usually right at 22 at idle and cruise. honestly I don't recall the # on takeoff, lemme see if I wrote that down anywhere.
     
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  2. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    I'm curious what you have for a gauge then, and where it's measuring.

    A fuel flow gauge should measure pressure at the fuel distributor, and read an output as a number in fuel flow (since the way these systems work is more pressure = more flow). The number at idle should be very low, near the bottom of the gauge, and the number at cruise should be very high, near the top. 20-25 GPH at takeoff sounds right, but saying 22 at idle and cruise doesn't make sense.

    Now if your gauge measures pressure before it goes into the servo, that would make sense. But that means it won't tell you flow and thus you won't have the effect I described on my Aztec.

    Similarly, if you have a digital fuel flow gauge that uses a transducer that actually measures flow, then that will give you... actual flow (assuming it's calibrated correctly).

    Regardless, first step I'd take is cleaning the injectors. It's virtually free and can't hurt anything.
     
  3. Grum.Man

    Grum.Man Cleared for Takeoff

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    With a constant speed propeller you should be able to see max flow rate on a full power ground run up. The engine manual will tell you what that value should be. Which pattern did the other two injectors follow, the disrupted looking flow or the nice clean stream?

    This is again considering you have a fuel flow gauge with a transducer inline.
     
  4. Stingray Don

    Stingray Don Pattern Altitude

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    Perhaps one injector thinks it is a Mooney and the other a Bonanza. :D
     
  5. eman1200

    eman1200 Final Approach

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    this is the gauge, I'll check the #'s, maybe I'm wrong with the idle #'s.

    IMG_1123.JPG
     
  6. eman1200

    eman1200 Final Approach

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    the others flowed like the first one in the vid. mechanic said he moved the bad nozzle around to the other lines and the erratic flow followed the nozzle.
     
  7. Grum.Man

    Grum.Man Cleared for Takeoff

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    I'm assuming a compression test has been done to check the health of the valves?
     
  8. eman1200

    eman1200 Final Approach

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    three compression checks have been done
     
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  9. Checkout_my_Six

    Checkout_my_Six Final Approach

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    ya know what?....they have a pill for that. ;)
     
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  10. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    The fuel pressure gauge you showed (and the green arc that goes with it) makes me think that it shows the fuel pressure going into the servo, and not the fuel flow/pressure at the distributor. That fuel pressure that you see there should basically be constant at higher RPM or when the boost pump is on. With the boost pump off you should expect to see it lower at idle and higher at full power, although how much higher I can't recall.
     
  11. Bill Jennings

    Bill Jennings Final Approach

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    @Ted DuPuis , Hoppes as in the gun cleaner? I don't believe we've ever cleaned the injectors, so I need to look into it.
     
  12. eman1200

    eman1200 Final Approach

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    yes
     
  13. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    Correct. Stuff works great. Some use ultrasonic cleaners and those work well, too.
     
  14. overdrive148

    overdrive148 En-Route

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  15. Checkout_my_Six

    Checkout_my_Six Final Approach

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    I'm going with a plugged up fuel distributor......;)

    [​IMG]
     
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  16. FlySince9

    FlySince9 Pattern Altitude

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    My question is why they focused on the Mags before first checking all the lesser expensive possibilities (like most mechanics would). The symptoms pointed to spark or fuel, yet they got tunnel vision on the mags... Really sorry see you go through all of that, E....
     
  17. eman1200

    eman1200 Final Approach

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    they said they checked the nozzles. maybe they did, maybe they didn't, but the problem was intermittent so maybe they DID check but the prob wasn't there at the time. OR, you know, these guys suck.
     
  18. N659HB

    N659HB Pattern Altitude

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    Gonna use them for the annual? :rolleyes:
     
  19. GlennAB1

    GlennAB1 Ejection Handle Pulled

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    Intermittent problems are challenging to troubleshoot. I'd suspect ignition before fuel every time, just based on experience, but, if you're going to start throwing money at it, rule out the lower cost possibilities first.
     
  20. FlySince9

    FlySince9 Pattern Altitude

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    Why not...they about did most of the annual trying to fix this... can't be too much left to sign off...
     
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  21. FloridaPilot

    FloridaPilot Pattern Altitude

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    @eman1200 As a side note the guy at 48X never sold that Mooney.
     
  22. eman1200

    eman1200 Final Approach

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    yikes! yeah that one was asking way too much for the condition it was in.