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Whipple / BAP / Fuel pressure issue - help!!

Discussion in 'Terminator Talk' started by Jiffy, Mar 24, 2017.

  1. Jiffy

    Jiffy Active Member Established Member

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    Hi guys
    I have posted occasionally about my car - I'm in Australia and there is very little experience with these cars here and I have modded my car and my tuner is struggling a little, but because there aren't any other Terminators here, no one else has any more experience that I could take it to. So -

    I have a 2002 Cobra, 5 years ago I put in a 2003 Cobra drivetrain with a 2.8in pulley, 6-speed trans, 03 fuel tank and pumps, 03 FPDM etc and all good for 5 years. Only 417rwhp and it dropped off quite quickly after 5500, but it ran reliably and I was very happy.

    So, fast forward to this year and my mechanic has put on a 2.3L Whipple with a 3inch pulley, a SBTB, 60lb injectors, JLT CAI, BA2600 MAF, 20a BAP (later edit - this is a 40a unit), 3 inch exhaust and Hi-Flo cats. It fired up perfectly but obviously needs a tune.

    So, I booked it into a local tuner who comes highly recommended for tuning the local Australian 5.0L S/C and 4.0L Turbo FPV cars and they're really struggling - due to the age of the car, the codes and software required and knowledge of what does what in the tune.

    So - the current state of affairs is this: The car runs, makes lots of boost but is building too much fuel pressure at idle.
    At idle, the pressure is going up towards 100lbs even with the BAP adjusting knob turned down. They're suggesting that to resolve this I need an external regulator and a return system, probably located just outside the pump and that will allow excess fuel pressure to be routed back. While I can understand that this is likely to work, it seems odd that they cannot find a way to 'turn down' the fuel pressure through the mapping, and this just may be an experience thing.

    When I talk to them, they say they've tried turning the fuel pressure down in the tune, adjusted the duty cycle of the injectors etc but the issue is still excess pressure at idle.

    SO - is there anyone who has had specific tuning experience with these cars, who might have come across this issue, struggled with it then had a 'lightbulb' moment and figured out how/where to adjust and control the pumps better actually within the tune, rather than put in an external regulator and return system - or is that really the only way to go?

    Sorry for the long post guys, but my car has been there 7 weeks today and I would like it back and I guess they would like the room...
     
    Last edited: Mar 26, 2017
  2. MG0h3

    MG0h3 Well-Known Member Premium Member Established Member

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    First thing I would look at is how the FPDM got wired in; my first guess is that the FPDM is maxing the pumps out all the time.

    Also, take a look at the Fuel Rail Pressure Sensor. Not quite sure how everything is setup on the car with the swap and all.
     
  3. Jiffy

    Jiffy Active Member Established Member

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    From memory we checked it - harness, FPDM, BAP, pumps. All done according to the KB instructions. You can hear the pumps spool up at idle if you turn the knob.
     
  4. Jiffy

    Jiffy Active Member Established Member

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    WRT the pressure sensor, that was done according to how a 2003 would be done - engine bay harness was swapped out and the 2003 harness ECU and fuel rail was installed.
     
  5. Jiffy

    Jiffy Active Member Established Member

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    Plus, the FPDM worked before with the Eaton - must have been installed correctly??
     
  6. speedoflife

    speedoflife Active Member Established Member

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    I think your own "lightbulb" moment should be getting a new tuner.

    I mean no offense to your other tuner, but why risk blowing up your motor (not easy to replace in Aus. I'm sure!!!) and ruining all that good money you spent? Were I you, I'd get my car remote tuned. The tune can totally make or break a car, and there are SO many good tuners with fantastic reputations that would happily tune your car from across the ocean. 04sleeper, Lund, VMP, etc
     
  7. speedoflife

    speedoflife Active Member Established Member

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    Sorry for the double post, but also a 20A BAP with a 2.3 Whipple isn't gonna cut it IMO. It might get you there, but I don't think it will leave comfortable headroom. Maybe it will, but I can get over 80% FPDC with a wire-upgraded 40A BAP on an unported Eaton.

    Is your BAP wired pre- or post-FPDM?
     
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  8. Jiffy

    Jiffy Active Member Established Member

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    Post FPDM.
     
  9. Jiffy

    Jiffy Active Member Established Member

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    So, I guess I'd like to hear from experienced tuners - how cookie-cutter is the tuning of these things with these level of mods? How confident would you be loading in a tune you've used before without checking air/fuel etc?
     
  10. 03' White Snake

    03' White Snake Well-Known Member Established Member

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    1.) Do you have a cobra dual pump setup in the tank? You need a 40A BAP with dual cobra pumps. The back of the KB BAP will be stamped 30 if it is a 40A unit.
    2.) Wire the BAP pre-FPDM. They are very hard to tune when installed after the FPDM because the computer has no idea what the pumps are doing. You should connect the BAP in the Green/Yellow wire on the FPDM harness before it plugs into the FPDM.
    3.) Wire the BAP full on all the time. Cut the hobbs switch wires and the knob wires 12" from the BAP and connect each set of wires together. The 2 from the hobbs go together and the 2 from knob go together.
    4.) Make sure the BAP is grounded.
     
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  11. Jiffy

    Jiffy Active Member Established Member

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    Hi - thanks for the post. The KB instructions say '03 Cobra (I have dual pumps) should be wired with the BAP connected POST FPDM, not pre?
    Can anyone confirm pre or post FPDM. And it's only a 20a BAP (later edit - 40a BAP) but the PO had run it on his Cobra ok.
    Hobbs switch is removed & hard wired.
     
    Last edited: Mar 26, 2017
  12. RI-SVT

    RI-SVT TVS Powered Established Member

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    yes should be Pre, Never read of people running a 20A BAP on these cars.
     
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  13. MG0h3

    MG0h3 Well-Known Member Premium Member Established Member

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    Makes sense jiffy. If the fpdm doesn't have the return signal from the pumps I bet it just maxes them out.


    Sent from my iPhone using svtperformance.com
     
  14. Bdubbs

    Bdubbs u even lift bro? Established Member

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    The bap itself does nothing for adding more fuel or fuel pressure. Your tuner should hopefully know that. It helps supply more voltage to the pumps when needed. Always wire "pre" fpdm like others mentioned.
     
  15. Jiffy

    Jiffy Active Member Established Member

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    Excellent - anyone have a wiring diagram I can send to my tuner to modify it?
     
  16. Jiffy

    Jiffy Active Member Established Member

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    - later edit - removed.
     
    Last edited: Mar 26, 2017
  17. jblood37

    jblood37 Well-Known Member Established Member

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    Contact 04sleeper on these forums. It's not a canned tune like what you're thinking. The initial start up is, but then you data log and send him files that show him exactly how your car is running. It's the same thing you would do if getting dyno tuned, but imo it's actually better.
     
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  18. Jiffy

    Jiffy Active Member Established Member

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    Where do I get the data log from??? I'm a total noob to this so I'd need to be walked through it...
     
  19. Jiffy

    Jiffy Active Member Established Member

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    Some good news - just checked my original purchase - the BAP is a 40A unit! Phew....
     
  20. jblood37

    jblood37 Well-Known Member Established Member

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    I use my sct handheld. Plug one end into obd2 and the other into a laptop. I use the sct software to datalog with.
     

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