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Thread: Turbo ls breakup/flutter/ bouncing boost gauge

  1. #1
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    Default Turbo ls breakup/flutter/ bouncing boost gauge

    So got the car going. p59 3bar sd. Fic1200 ngk tr7ef plugs at .018 base fuel pressure is 38 in effort to lean out idle. Car ran great! At 10psi 13⁰ timing pump 91. Drove it back and forth to work for a week or so logging doing ve corrections the whole time. Then kind of with out warning it started popping/fluttering at the transition from vac to boost. If you floor it it kind of pulls thru but runs poorly. Still makes 10psi but has no power at all. Timing is stable .83-.85 on fuel in power .95 cruise. Plug wires look fine. Just put another set of plugs in gapped at .018. No affect on the issue. Thought maybe couls could be heating up. Possibly plugged injectors? When it starts popping it goes from commanded fuel of .83 real lean the real rich and the boost gauge just bounces all over the place.

  2. #2
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    Can someone move this where it goes please not sure this is where it belongs

  3. #3
    Joe (Moderator) joecar's Avatar
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    Post logs.

    Did you scale the IFR table for 38 psi...? Are the injector tables correct...?

    Is plug gap 0.018" too close...? What do the ends of the plugs look like...?

    How would you determine clogged injectors...?

    Is the FPR ok (i.e. diaphragm is not leaking)...?

    Is FPR manifold referenced...? If so, is IRF table straight flat...?

  4. #4
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    Yes i believe injector tables are fine it ran extremely well for a week or so while tuning. As far as plug gap goes it was recommended to me that i run a .018 on stock coils if its correct or not im not sure. Diaphragm is okay in fuel psi regulator and yes the regulator is boost ref and the ifr table is flat lined.

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    I will try and post some logs once i get the plugs cleaned

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    So did a little more investigating now that im not a upset about the situation did a cylinder cut out since misfire data is not working as it should #4 & #7 have no affect on idle when cut out. However if they are cut out then turned back on i get a small pop out the exhuast which maybe im being optimistic but hopefully that means compression is okay and the plugs or coils are just junk fingers crossed.

  7. #7
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    Update pulled plugs checked compression on what i thought were the suspect holes. 4/7 both had around 130psi cranking. Put plugs back in. Started it up started un plugging coil packs to find dead holes. Now apparently 6 and 8 are dead. Not sure what is going on but its going to come to a head tomorrow.

  8. #8
    Joe (Moderator) joecar's Avatar
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    Check coil bracket subharnesses, in some instances the left and right subharnesses are not quite identical (2 pins transposed).

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    Just typed a novel then it got deleted found what i can only guess is the issues. What appears to be dirt in the injectors. Cleaned them out as good as i could reinstalled them ran okay-ish. Ordered a 10micron filter snake eater 1000s and will report back if its fixed thanks for the help and suggestions joecar

  10. #10
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    Good news! Dropped the SEP1000s and the aeromotive 10micron in thoroughly flushed the fuel system from pump to rails. Got injector data in. Naturally my VE table was wrecked due to me trying to compensate for plugged/plugging injectors. Got it into boost pig rich but will get it tuned in this week and be ready for some more closed course test hits later this week!

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