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

Back Firing

  • Thread starter Thread starter mustang 88
  • Start date Start date Dec 5, 2013
M

mustang 88

Member
Oct 21, 2012
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cleveland ga
Dec 5, 2013
#1
  • Dec 5, 2013
  • #1
Please help any ideals welcomed. When I let off the throttle it rumbles down but it is loud enough I would consider it a back firing down. Stock bottom end, E-303 cam, 185 afr heads, 75 mm throttle body,24 lb fuel injectors, timing on 11 degree, egr delete, fuel pressure at 38 lbs,1.7 rockers.
 

A5literMan

At least it is lumpy...
5 Year Member
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Dec 5, 2013
#2
  • Dec 5, 2013
  • #2
I'll be first. Did you run the codes? What kind of ignition are you running? And more explanation on sound/activity you are experiencing.
 

84Ttop

They make new pistons every day, so why worry?
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Dec 5, 2013
#3
  • Dec 5, 2013
  • #3
What exhaust is on the car specifically?
 
M

mustang 88

Member
Oct 21, 2012
60
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9
cleveland ga
Dec 5, 2013
#4
  • Dec 5, 2013
  • #4
A5literMan said:
I'll be first. Did you run the codes? What kind of ignition are you running? And more explanation on sound/activity you are experiencing.
Click to expand...
A5literMan said:
I'll be first. Did you run the codes? What kind of ignition are you running? And more explanation on sound/activity you are experiencing.
Click to expand...
Did not dump codes.
A5literMan said:
I'll be first. Did you run the codes? What kind of ignition are you running? And more explanation on sound/activity you are experiencing.
Click to expand...
Did not run codes. I have a MSD 6al ignition box, factory dist, only sounds like a back fire when coasting off the throttle.
 
M

mustang 88

Member
Oct 21, 2012
60
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cleveland ga
Dec 5, 2013
#5
  • Dec 5, 2013
  • #5
84Ttop said:
What exhaust is on the car specifically?
Click to expand...
Not sure of brand but it is 1and 5/8 primary long tube headers into 2 and 1/2 inch flow master super 44's
 

A5literMan

At least it is lumpy...
5 Year Member
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Dec 5, 2013
#6
  • Dec 5, 2013
  • #6
Highly recommend dumping codes first. Find out if it's any computer,sensor,etc problems. Do that before throwing parts at it. Also fwiw a few people have been claiming MSD have been having problems with their ign boxes.
 

84Ttop

They make new pistons every day, so why worry?
5 Year Member
Jul 2, 2009
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Dec 5, 2013
#7
  • Dec 5, 2013
  • #7
Any sort of cross over or x pipe?
 

84Ttop

They make new pistons every day, so why worry?
5 Year Member
Jul 2, 2009
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Dec 5, 2013
#8
  • Dec 5, 2013
  • #8
A5literMan said:
Highly recommend dumping codes first. Find out if it's any computer,sensor,etc problems. Do that before throwing parts at it. Also fwiw a few people have been claiming MSD have been having problems with their ign boxes.
Click to expand...
my experience with the msd failures is it either works or it doesnt, fwiw
 
Reactions: A5literMan

Grabbin' Asphalt

10 Year Member
Jun 10, 2013
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Dec 5, 2013
#9
  • Dec 5, 2013
  • #9
Also if you mix grades of gas and different brands it will act similar when you coast, downshift etc, ....run it near dry and fill up with some higher octane.
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
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Dec 5, 2013
#10
  • Dec 5, 2013
  • #10
Backfiring usually points to a lean condition.

With your mods, I ask if you ever had a tune done? Are you using a mAF calibrated for the 24s?

The EGR being deleted may also play a role.

First thing to do is run the codes and address what comes up. There is no fuctional check engine light in an 88, so it doesn't hurt to buy the $20. Equus 3145 code reader and get in the habit of running codes
 
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85rkyboby

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Mar 2, 2011
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Dec 5, 2013
#11
  • Dec 5, 2013
  • #11
Mustang5L5 said:
Backfiring usually points to a lean condition.

With your mods, I ask if you ever had a tune done? Are you using a mAF calibrated for the 24s?
Click to expand...
I thought lean was a backfire through the carb (I understand the owner's is EFI)? Insight will help my knowledge, thanks.
 
M

mustang 88

Member
Oct 21, 2012
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cleveland ga
Dec 5, 2013
#12
  • Dec 5, 2013
  • #12
84Ttop said:
Any sort of cross over or x pipe?
Click to expand...
x pipe
 
M

mustang 88

Member
Oct 21, 2012
60
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9
cleveland ga
Dec 5, 2013
#13
  • Dec 5, 2013
  • #13
Grabbin' Asphalt said:
Also if you mix grades of gas and different brands it will act similar when you coast, downshift etc, ....run it near dry and fill up with some higher octane.
Click to expand...
Always run high octane never mix becausethe guy before me shaved the block now I have 10.4 to 1 compression
 
M

mustang 88

Member
Oct 21, 2012
60
4
9
cleveland ga
Dec 5, 2013
#14
  • Dec 5, 2013
  • #14
85rkyboby said:
I thought lean was a backfire through the carb (I understand the owner's is EFI)? Insight will help my knowledge, thanks.
Click to expand...
I always heard the same guess i'll have to go get a code reader maybe time to upgrade fuel pump
 
Reactions: 85rkyboby

A5literMan

At least it is lumpy...
5 Year Member
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Dec 5, 2013
#15
  • Dec 5, 2013
  • #15
mustang 88 said:
Always run high octane never mix becausethe guy before me shaved the block now I have 10.4 to 1 compression
Click to expand...
Kinda curious here. You say you've got stock bottom end,SHAVED block, e cam,185 Afrs,and 1.7 rr. My ?? How do you have ptv clearance? Are the pistons notched? I've always heard there is clearance issues with 2.02 valves in the Afr 185. And you decked the block enough for over 1 pt in compression?
 
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