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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Top end woes

  • Thread starter Thread starter David Schwarz
  • Start date Start date Jan 1, 2004
D

David Schwarz

New Member
Mar 7, 2003
127
0
0
San Diego, CA
Jan 1, 2004
#1
  • Jan 1, 2004
  • #1
Still trying to get all of the bugs out of the new motor. I have a favorite uphill onramp near my house where I can really get on it. Discovered today that at 5500 rpm, the motor starts to backfire big time, but is fine when I shift to the next gear. I'm using a MSD 6AL with the YS trim blower (11# boost at 5700 rpm based on dyno pull). My mechanic said I didn't need the MSD 6BTM bacause I don't have a detonation problem (and this is definitely not detonation, I've had that with the old motor and know the sound well). I should point out that she seems to run fine on level ground, though I haven't had a chance to really test this carefully yet .

So what's causing the top end backfire/sputter. Could this be related to the absence of a boost timing master? I don't want to damage my new motor before it even sees its first trip to the track.
 

88stangmangt

Active Member
Nov 25, 2003
2,332
1
48
Stafford,VA
Jan 1, 2004
#2
  • Jan 1, 2004
  • #2
might be just cause you have hit the limit of your engine could if be caused by floating lifters? i loose it around there too.
 

mike keirstead

New Member
Aug 6, 2003
1,121
0
0
ROLLING A JOINT
Jan 1, 2004
#3
  • Jan 1, 2004
  • #3
Yes...floating valves or fuel pump maybe...mine used to back fire when it was lean...many things will cause BF
 
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