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Massive backfiring

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Old Oct 1, 2005 | 07:52 PM
  #1  
KillSwitchNY's Avatar
KillSwitchNY
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From: NY
Default Massive backfiring

ok so today i took off my stock mass air sensor and replaced it with a 75mm Pro-M calibrated for my 24# injectors.....

the car now runs like sht

i time my car all the time because i am crazy about it being perfect,,, being that i have stock gears i can feel every lack of power there is

i adjusted my fuel psi to 45 psi and timed it at 16*then 15, 14, 13... i stopped at 13* and the car still pops like a motherfcker its sometimes inside the header and most of the time all the way out the tailpipes....

the car is also running rough i figured geting the right mass air would solve my problem of fuel delivery but i guess so far its dont more harm than good....

any ideas on what the timing and fuel pressure should be
Old Oct 1, 2005 | 07:57 PM
  #2  
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89stanglx
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Default RE: Massive backfiring

i would set the timing to stock 10deg for now and i think most people set the fuel pressure around 38-40
what stock maf meter do you have i noticed you have a 88 and thats speed density"unless a california model", and if it was converted to maf, a stock maf is calibrated for 19lb injectors
Old Oct 1, 2005 | 08:00 PM
  #3  
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Default RE: Massive backfiring

^ he's right i'm only running 42 psi with 18* and it still runs rich at times...if your motor is basically stock start with 38psi...and 12*
Old Oct 1, 2005 | 08:24 PM
  #4  
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KillSwitchNY
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Default RE: Massive backfiring

no it was converted to mass air sorry forgot to mention that...

anyway i have 24# injectors, so i took off the stock 55mm 19lb mass air sensor and replaced it with the 75mm calibrated for 24's

i have 302 bored to 306 edelbrock performer rpm head gt40 upper and lower intake e303 cam, just a cone high flow air filter nothing fancy, msd 255lph walbro fuel pump and the adjustable regulator,,,, i guess ill set it at ten the go up from there right? and set the fuel to 40psi?
Old Oct 1, 2005 | 08:33 PM
  #5  
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KillSwitchNY
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Default RE: Massive backfiring

ive also been adjusting my fuel pressure according to what my saleen fuel pressure guage i have in the vents tells me do you know if this is accurate... i always remove the vaccumme line from the regulator before adjusting it too.... also the fuel pressure guage is never steady it is always rapidly bouncing in between say 5 psi intervals depending where i set it whats up with that? is the fuel psi supposed to be somewhat steady?
Old Oct 1, 2005 | 08:35 PM
  #6  
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grabbem88
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From: cape giradeau,mo
Default RE: Massive backfiring

conversions are always fun i fought with mine twice....mine did what you were saying,but my o2 harness had a wire broke i unplugged it,and it was fine..although very rich.
Old Oct 1, 2005 | 08:37 PM
  #7  
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grabbem88
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From: cape giradeau,mo
Default RE: Massive backfiring

it should should be somewhat steady but will fluctuate a little.
Old Oct 1, 2005 | 09:06 PM
  #8  
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KillSwitchNY
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Default RE: Massive backfiring

yeah my car used to be badly rich it would smell inside my house when the car was running out in the street.... now it isnt as bad ... next step,,,, get MORE air in the motor... 70 mm throttle body


also a code read that my tps was out of range... the tps was previously honed out to move it further over.... i might wait until i get the throttle body and just do a new tps sensor..... i dont know yet
Old Oct 1, 2005 | 09:09 PM
  #9  
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grabbem88
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From: cape giradeau,mo
Default RE: Massive backfiring

yeah you need a t-body i bought an accufab 70mm,and i love it qaullity is right up there too.....one more thing did you reset the computer???it might still be thinking 19lbs.....??
Old Oct 1, 2005 | 09:13 PM
  #10  
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Default RE: Massive backfiring

sorry re read your post and had to edit



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