Author
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Topic: popping sound from exhaust
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slow5oh
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Member # 12881
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posted
so when I slow down from high rpm's there is a lot of popping coming from my exhaust, should this be something I should worry about? also happens when I downshift. [ 2013-07-15, 11:47 AM: Message edited by: slow5oh ]
-------------------- '90 LX Mustang SIKWIDIT CAR CLUB
Posts: 75 | From: American Canyon | Registered: Apr 2013
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NEIGHT
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Member # 8741
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posted
Are you talking about slowing down as in engine brake(no gas or clutch still in gear). If so yes it's normal for aftermarket exhaust to pop without cats.
-------------------- -Savage Habits- 1992 Summer Edition 1986 Hatch- catfish killer 1964 Impala hard top
Posts: 18548 | From: EA$T $IDE REDWOOD CITY | Registered: Nov 2008
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norcalfiddy
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Member # 11207
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posted
timing, running rich
nothing to worry about
-------------------- 600HP 1996 7.3L powerstroke single cab short bed race truck
Posts: 3393 | From: Brentwood | Registered: Aug 2011
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redvenom
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Member # 12651
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posted
quote: Originally posted by NEIGHT: Are you talking about slowing down as in engine brake(no gas or clutch still in gear). If so yes it's normal for aftermarket exhaust to pop without cats.
Yea I like that sound
-------------------- 1990 Gt Some what stock 1993 GT vert-(stolen)
Posts: 623 | From: cali | Registered: Dec 2012
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slow5oh
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Member # 12881
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posted
quote: Originally posted by red5o: quote: Originally posted by NEIGHT: Are you talking about slowing down as in engine brake(no gas or clutch still in gear). If so yes it's normal for aftermarket exhaust to pop without cats.
Yea I like that sound
lol I have all my cats on though
-------------------- '90 LX Mustang SIKWIDIT CAR CLUB
Posts: 75 | From: American Canyon | Registered: Apr 2013
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S351-R
CAFords OG
Member # 1605
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posted
If it backfires excessively and you still have a functional air pump, you may have an air pump diverter valve not functioning properly. [ 2013-07-16, 12:22 PM: Message edited by: S351-R ]
Posts: 344 | From: Earth | Registered: Jul 2002
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slow5oh
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Member # 12881
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posted
quote: Originally posted by S351-R: If it backfires excessively and you still have a functional air pump, you may have an air pump diverter valve not functioning properly.
it's bot backfiring though, when I engine brake it just sounds like a lot of little pops like I have popcorn in my trunk
-------------------- '90 LX Mustang SIKWIDIT CAR CLUB
Posts: 75 | From: American Canyon | Registered: Apr 2013
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coupe5oh
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Member # 10411
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posted
its actually a sign of weak valve springs. on decel the vacuum from the pistons going down is pulling the valves open. it did it on my old 94 but when I rebuilt the engine with new valve springs it never did it again. I didn't know why until my old auto shop teacher explained it to me
-------------------- R.I.P Willie Guzman (5ltrsvt) 96 4.6- H/C/I 5.3 LS swap 95 5.0- SOLD 94 5.0- SOLD
Posts: 2288 | From: Hayward | Registered: Oct 2010
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slow5oh
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Member # 12881
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posted
quote: Originally posted by coupe5oh: its actually a sign of weak valve springs. on decel the vacuum from the pistons going down is pulling the valves open. it did it on my old 94 but when I rebuilt the engine with new valve springs it never did it again. I didn't know why until my old auto shop teacher explained it to me
this won't affect anything when I smog right?
-------------------- '90 LX Mustang SIKWIDIT CAR CLUB
Posts: 75 | From: American Canyon | Registered: Apr 2013
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coupe5oh
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Member # 10411
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posted
quote: Originally posted by slow5oh: quote: Originally posted by coupe5oh: its actually a sign of weak valve springs. on decel the vacuum from the pistons going down is pulling the valves open. it did it on my old 94 but when I rebuilt the engine with new valve springs it never did it again. I didn't know why until my old auto shop teacher explained it to me
this won't affect anything when I smog right?
it shouldn't being that smog is tested under power not decal..my 95 gt does it and I passed smog no problem with a smog legal C.A.I and stock exhaust
-------------------- R.I.P Willie Guzman (5ltrsvt) 96 4.6- H/C/I 5.3 LS swap 95 5.0- SOLD 94 5.0- SOLD
Posts: 2288 | From: Hayward | Registered: Oct 2010
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slow5oh
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Member # 12881
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posted
okay sounds good, thanks guys
-------------------- '90 LX Mustang SIKWIDIT CAR CLUB
Posts: 75 | From: American Canyon | Registered: Apr 2013
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coupe5oh
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Member # 10411
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posted
no problem
-------------------- R.I.P Willie Guzman (5ltrsvt) 96 4.6- H/C/I 5.3 LS swap 95 5.0- SOLD 94 5.0- SOLD
Posts: 2288 | From: Hayward | Registered: Oct 2010
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