"Air Injector Check Valve" - Cat. tube...exhaust related

slo95 · 10-24-2001, 09:08 PM

with the help on some users here, I am slowing narrowing down my "whirring" noise.
1995 GT -
Question is, there are two Air Check Valves connected to the smog gear...One goes to the back of the heads, and the other is fixed on the end of the tube from the Catalytic converters.

The valve going to the heads only flows air into the heads, not out, verified and okay...

Which way should the other flow (the one welded onto the tube from the Cat's) ? I am guessing from the smog gear to the Cats, from engine to exhaust. Is this correct? So, If I feel exhaust pulses from this check valve with the engine at idle, that is bad, because air should be going out to the cats, and not into the engine from them?

Might also cause the AIR Diverter to go bad too, putting reverse flow to it?

PKRWUD · 10-25-2001, 01:38 AM

Yes, and yes. Air flows to the cats to warm them up. Check valve keeps the super hot cat exhaust from coming back (usually from an exhaust backfire).

Take care,
-Chris

------------------
Retired Moderator
MustangNet

My site: Peckerwoods Pit Stop

My teams site: Jim Porter Racing

RACECAR spelled backwards is RACECAR

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slo95 · 10-25-2001, 09:00 AM

thanks,
guess I am swapping out that valve...I have noticed too, at slow down (without brakes, kinda engine braking - but auto tranny) I get that little backfire rumble...backfires can be due to bad check valves too, right?

10-24-2001, 09:08 PM	#1
slo95 Registered Member Join Date: Dec 2000 Posts: 168	"Air Injector Check Valve" - Cat. tube...exhaust related with the help on some users here, I am slowing narrowing down my "whirring" noise. 1995 GT - Question is, there are two Air Check Valves connected to the smog gear...One goes to the back of the heads, and the other is fixed on the end of the tube from the Catalytic converters. The valve going to the heads only flows air into the heads, not out, verified and okay... Which way should the other flow (the one welded onto the tube from the Cat's) ? I am guessing from the smog gear to the Cats, from engine to exhaust. Is this correct? So, If I feel exhaust pulses from this check valve with the engine at idle, that is bad, because air should be going out to the cats, and not into the engine from them? Might also cause the AIR Diverter to go bad too, putting reverse flow to it?

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10-25-2001, 01:38 AM	#2
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Yes, and yes. Air flows to the cats to warm them up. Check valve keeps the super hot cat exhaust from coming back (usually from an exhaust backfire). Take care, -Chris ------------------ Retired Moderator MustangNet My site: Peckerwoods Pit Stop My teams site: Jim Porter Racing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN.

10-25-2001, 09:00 AM	#3
slo95 Registered Member Join Date: Dec 2000 Posts: 168	thanks, guess I am swapping out that valve...I have noticed too, at slow down (without brakes, kinda engine braking - but auto tranny) I get that little backfire rumble...backfires can be due to bad check valves too, right?