Backfiring??

skiwesser · 06-15-2005, 06:32 PM

What would cause it to backfire on WOT 1-2 & 2-3 shifts?
I dont't think I have any exhuast or intake leaks, how can these be checked for? None audiable.

HotRoddin · 06-15-2005, 06:38 PM

At what RPM ? Maybe you're floating the valves ?

Capri306 · 06-15-2005, 07:56 PM

If you have the air injection reactor (air pump) system still on your car, replace the one-way check valves and check to see that the diverter and atmospheric dump valves are operating and properly connected. That or you're getting air introduced into the exhaust where and/or when it shouldn't be.

On the other hand, if you're leaning out, you need to check the fuel pressure while on a WOT run.

Hope this helps.

skiwesser · 06-15-2005, 10:14 PM

It does it when I powershift at 5200-5400RPM.
Smog stuff all gone.
Have pressure guage on shrader valve. Adjustable FPR set at 40psi.
190lph pump

skiwesser · 06-19-2005, 01:48 AM

I replaced blown header gasket, found a bad wire.
Backfiring much less, but still once out of eight or ten shifts, ecespecially on the spray (60 shot)

06-15-2005, 06:32 PM	#1
skiwesser Registered Member Join Date: Sep 2000 Location: rock hill,S.C. 29730 Posts: 420	Backfiring?? What would cause it to backfire on WOT 1-2 & 2-3 shifts? I dont't think I have any exhuast or intake leaks, how can these be checked for? None audiable. __________________ 88 GT: subs,pullies, 1 3/4 longtubes, flowmasters, AFR 165's,T,F #1 cam,Thyphoon intake, 24# inj., 73mm C&L,65mmT.B., 190LPH pump, Eagle sir rods, forged pistons in a newly rebuilt 306. DYNO TUNED TO 300.97 RWHP 337RWTQ

06-15-2005, 06:38 PM	#2
HotRoddin cranky old man Join Date: Sep 2001 Location: Longview Texas Posts: 683	Re: Backfiring?? At what RPM ? Maybe you're floating the valves ? __________________ Under Construction: 64 Falcon 372 cu in. stroker 1:72 rod ratio 6.250" rods (long rod), Comp Cams XE274 230/236 520/526 @ .050, Scorpion Rollers, Roush 200 irons, 10:1 Keith Blacks, Hedman long tubes, 750 Holley DP, Edelbrock Victor Jr., C4 3500 stall, gears and tires to be anounced.

06-15-2005, 07:56 PM	#3
Capri306 Moderator Join Date: Sep 1998 Location: Grand Rapids, Michigan, USA Posts: 1,001	Re: Backfiring?? If you have the air injection reactor (air pump) system still on your car, replace the one-way check valves and check to see that the diverter and atmospheric dump valves are operating and properly connected. That or you're getting air introduced into the exhaust where and/or when it shouldn't be. On the other hand, if you're leaning out, you need to check the fuel pressure while on a WOT run. Hope this helps. __________________ Capri306, Moderator The Mustang Works Online 1979 Mercury Capri 1987 5.0L Mustang LX Notchback 1993 5.8L Eddie Bauer Bronco

06-15-2005, 10:14 PM	#4
skiwesser Registered Member Join Date: Sep 2000 Location: rock hill,S.C. 29730 Posts: 420	Re: Backfiring?? It does it when I powershift at 5200-5400RPM. Smog stuff all gone. Have pressure guage on shrader valve. Adjustable FPR set at 40psi. 190lph pump __________________ 88 GT: subs,pullies, 1 3/4 longtubes, flowmasters, AFR 165's,T,F #1 cam,Thyphoon intake, 24# inj., 73mm C&L,65mmT.B., 190LPH pump, Eagle sir rods, forged pistons in a newly rebuilt 306. DYNO TUNED TO 300.97 RWHP 337RWTQ

06-19-2005, 01:48 AM	#5
skiwesser Registered Member Join Date: Sep 2000 Location: rock hill,S.C. 29730 Posts: 420	Re: Backfiring?? I replaced blown header gasket, found a bad wire. Backfiring much less, but still once out of eight or ten shifts, ecespecially on the spray (60 shot) __________________ 88 GT: subs,pullies, 1 3/4 longtubes, flowmasters, AFR 165's,T,F #1 cam,Thyphoon intake, 24# inj., 73mm C&L,65mmT.B., 190LPH pump, Eagle sir rods, forged pistons in a newly rebuilt 306. DYNO TUNED TO 300.97 RWHP 337RWTQ

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