Engine Sputter

Discussion in 'Engine Tech' started by Cool Beans (Alex), Feb 15, 2017.

  1. Cool Beans (Alex)

    Cool Beans (Alex)
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    With or without boost, at random throttle levels the car will hit really hard and power will cut out. It sounds like the throttle blade just shuts, the boost goes all the way down, and my O2 readings go very low and sometimes get very little knock when in boost. If I roll into the throttle it doesn't do it as bad or frequently. It seems to happen the most when I just smash the throttle. Fuel pressure is good and climbs 1:1 with boost. I taped my phone under the hood and when power cuts out the fuel pressure goes back down to idle pressure.

    I am at a complete loss, here is everything I have replaced checked...

    -Plugs (ur5 gapped at .035 new)
    -Wires (MSD new)
    -Type 2 Ignition coil/module (both new)
    -Crank Sensor (New)
    -Cam sensor cap appears good, metal ring is solid (does not spin), car runs the same in batch fire with casensor unplugged
    -TPS (New)
    -MAF/MAF translator (New)
    -Injectors OHM good
    -TT 5.7 chip
    -Accufab pressure regulator (42 line off pressure)
    -Walboro fuel pump with hot wire kit


    If fuel pressure is steady and rises with boost what would make my O2 output drop so fast? I have a scanmaster but no data logger, What are some outputs I should check? I have been all over the forums for weeks and do not know what to check. Thank you for your guys time.
     
  2. mikestertwo

    mikestertwo
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    What does " really hits hard and power will cut out" mean? Do you mean the car is pulling hard and then shuts down? If the ignition is failing the O2's will lean out. What is the boost doing when this occurs. If the boost drops off then so will the fuel pressure. Need more info.
     
  3. Cool Beans (Alex)

    Cool Beans (Alex)
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    I just checked cam sensor again and it is making noise while the car is running like maybe the reluctor wheel is hitting the cap, would that be an issue? And I checked my positive cable and it is not hitting the downpipe

    Sent from my LGUS991 using Tapatalk
     
  4. TurboBuRick

    TurboBuRick
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    What are your settings in the translator?
     
  5. mikestertwo

    mikestertwo
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    If you mean it's making a tapping noise that usually means the bushings are worn and it should be replaced. Is it the cause of your problem? Really can't tell over the keyboard. It may sputter if the cam sensor is intermittent but the engine normally will not shut down as you described.
     
  6. Cool Beans (Alex)

    Cool Beans (Alex)
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    Settings on the translator are on-on-on-off setup for a standard chip. And the car never does it just goes to idle for a second and picks back up. The only things I have left are the cam sensor , injectors, or ecu

    Sent from my LGUS991 using Tapatalk
     
  7. TurboBuRick

    TurboBuRick
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    What about your air intake? What kind of pipe and air cleaner? its possible the air cleaner or flex pipe is collapsing.
     
  8. Cool Beans (Alex)

    Cool Beans (Alex)
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    It's a 3 inch pipe to the turbo with a come filter with a factory intercooler. And the silicone couplers would only collapse under vacuum and would blow off under boost

    Sent from my LGUS991 using Tapatalk
     
  9. Gene Van Horn

    Gene Van Horn
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    Put your scanmaster to volts, mash the pedal and see where your volts are at wot, possible interuption in your electrical causing the car to cut out.
     
  10. earlbrown

    earlbrown
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    First I would make sure the vacuum line to the FPR is new and zip tied. That one's easy to go over.


    Then it looks like you need to look closely at the hotwire kit and possible end up dropping the tank again.

    It sounds like you have an intermittent power problem, or a G-force problem.


    Would you say the cutting out is random or only happens when there are G-forces?
     
  11. Cool Beans (Alex)

    Cool Beans (Alex)
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    I've watched volts and they never drop below 13.5 and it only happens with G force, ill have to check trunk wires cause I had to splice them all. And I used brake clean on all vacuum hoses and could not find any. The vacuum gauge reads fairly steady at idle as well. The cutting out can be at low throttle as well though. And gets worse and more frequent when it's hot. I keep thinking about the cam sensor but it still has the same issue in batch fire mode when it's unplugged

    Sent from my LGUS991 using Tapatalk
     
  12. earlbrown

    earlbrown
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    I wasn't worried about vacuum leaks, I was concerned with a boost leak between the manifold and FPR.
     
  13. Cool Beans (Alex)

    Cool Beans (Alex)
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    Yeah I see, and I did zip the the hose and the issue is still there

    Sent from my LGUS991 using Tapatalk
     
  14. GNRick

    GNRick
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    Dead spot on TPS?
     
  15. earlbrown

    earlbrown
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    Then it sounds like you're sucking air or have an electrical problem that shows itself under acceleration.
     
  16. Cool Beans (Alex)

    Cool Beans (Alex)
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    Tps is new and I check for dead spots with key on, and that was my thought with electrical I guess I'll get to checking all connectors

    Sent from my LGUS991 using Tapatalk
     
  17. No disintegrations

    No disintegrations
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    Battery cables clean and tight at both ends? Grounds on back of head all in place or relocated?
     
  18. TurboTGuy

    TurboTGuy
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    This may sound silly, but are the coil pack connectors tightened down to the ignition module correctly?
     
  19. Cool Beans (Alex)

    Cool Beans (Alex)
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    Problem solved! I took it to a local Buick guy and he hooked up his oscilloscope and we found almost every injector driver in the ECU was bad. It was failing to send a signal to open injectors at random times. Now on to new issues haha thank you every one for your help

    Sent from my LGUS991 using Tapatalk
     
  20. TurboTGuy

    TurboTGuy
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    Glad you got it fixed.

    Electrical gremlins in these cars can drive one to the very edge of madness.
     

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