Backfire on Decel
Thread Starter
Junior Member
Joined: Aug 2005
Posts: 51
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From: Wisconsin
Car: 1951 Ford
Engine: Chevy 400 SB TPI
Transmission: 700R4
Axle/Gears: Ford 9 inch 373 gears
Backfire on Decel
Hello everyone,
Looking for some tips on what and where to start tunning. When the car starts to decel from 50 to 60 mph it back fires and pops and bangs. It does not sound very good. Just wondering if there is a tune tip to point me in the right direction.
Looking for some tips on what and where to start tunning. When the car starts to decel from 50 to 60 mph it back fires and pops and bangs. It does not sound very good. Just wondering if there is a tune tip to point me in the right direction.
Thread Starter
Junior Member
Joined: Aug 2005
Posts: 51
Likes: 0
From: Wisconsin
Car: 1951 Ford
Engine: Chevy 400 SB TPI
Transmission: 700R4
Axle/Gears: Ford 9 inch 373 gears
Re: Backfire on Decel
Hey thanks the closed throttle SA table seemed to help a lot. Just a little pop on decel now. I am going to try and add a little more fuel. What is DFCO?
Supreme Member

Joined: Aug 1999
Posts: 2,441
Likes: 1
From: sweden
Car: GTA -89
Engine: Blown 415"
Transmission: 4L80E
Axle/Gears: Strange 12-bolt
Re: Backfire on Decel
DFCO- Is Decel fuel cut off = No fuel at all, BPW=0 no tuning to do while DFCO just when it should enables and disables.
Lean pops under Decel is a "balance" between spark and fuel (as always....)
Lean pops under Decel is a "balance" between spark and fuel (as always....)
Thread Starter
Junior Member
Joined: Aug 2005
Posts: 51
Likes: 0
From: Wisconsin
Car: 1951 Ford
Engine: Chevy 400 SB TPI
Transmission: 700R4
Axle/Gears: Ford 9 inch 373 gears
Re: Backfire on Decel
I can't seem to find the DFCO spark setting? where is this located? Also what do you mean by BPW=0? If that is set to 0 then I don't need to change any other DFCO settings?
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From: Chasing Electrons
Car: check
Engine: check
Transmission: check
Re: Backfire on Decel
Don't rule out exhaust system leaks. That is the typical cause of backfires and bangs from the exhaust on a throttle lift.
RBob.
RBob.
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Supreme Member

Joined: Aug 1999
Posts: 2,441
Likes: 1
From: sweden
Car: GTA -89
Engine: Blown 415"
Transmission: 4L80E
Axle/Gears: Strange 12-bolt
Re: Backfire on Decel
BPW=0 is Base pulse Width is 0 injectors are not open at all, this is while DFCO is active. You must seperate DFCO and Decel two diffrent things.
Last edited by gta324; Aug 10, 2009 at 03:48 AM.
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