Installed New cat, should I hook the exhaust return up or no ?

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candymancan
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Joined: Tue Mar 22, 2016 11:32 pm

Installed New cat, should I hook the exhaust return up or no ?

Postby candymancan » Thu Oct 12, 2017 5:26 pm

The EGR on my 360 doesnt work. The EGR on mine is a newer style and has this nipple on the end of it with a vacuum hose, and i found that mine was clogged with rust from the nipple. After i replaced the line i found my engine would die, or not start or run like crap.. So my EGR is bad. So i just disconnected the line and plugged it with a screw.. And the engine runs fine like that. Not sure if im making sense here so here is a link to my EGR. The line i plugged is the one on the bottom left of the EGR itself.

https://www.partsgeek.com/ntd29rl-jeep- ... valve.html

Anyway, I just replaced the original cat. It was rattling like crazy and after i cut it off the honeycomb inside was in huge chunks. Replaced it with a Magnaflow cat, and wow my exhaust note is so nice with the new cat and my year old flowmaster 44.. Kinda cool how the cat can change the noise like that. Also got 40$ for my cat at the metal recycle plant.

Anyway, the cat i got has the little pipe on it which sends exhaust back to the engine. But i left the cap on it. Not sure if i should bother plugging it back up ? Or should I just remove the air pump and all the other emission crap on the engine ? I dont need to get my emissions done in Virginia since its over 25 years old. And the EGR doesnt work anyway, and TBH i dont plan to spend $120 on a new EGR anytime soon as i need the money for more important things. What do you guys think ?

I suspect the EGR not working is why the engine will ping with 87 octane in the fuel "higher combustion temps", but using 93/89 octane its fine, and TBH i only plan to use 93 in it anyway
2013 SS camaro, cammed, and modded too much to say 500 RWHP 30k
1998 Jeep Grand Cherokee 5.9L Limited 181k
1998 Jeep Grand Cherokee 4.0 I6 laredo 240k
1990 Jeep Grand Wagoneer 116k

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babywag
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Location: Land of Fruit Loops & Coconuts

Re: Installed New cat, should I hook the exhaust return up or no ?

Postby babywag » Thu Oct 12, 2017 6:56 pm

don’t need little CAT air tube hooked up.

it probably pings due to too much vacuum advance.
they’re adjustable most of time.

it should not ping if tuned properly even on 87.
whatever the reason it pings, be sure to resolve it.
pinging is a death sentence w/ stock cast pistons.
just because you cannot hear it pinging running 93 octane doesn’t mean it isn’t anymore.
it can occur w/o being audible.
Last edited by babywag on Thu Oct 12, 2017 7:05 pm, edited 2 times in total.
-Tony
'88 GW (aka Babywag) '90 GW (aka JunkBucket) both fuel injected.

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babywag
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Re: Installed New cat, should I hook the exhaust return up or no ?

Postby babywag » Thu Oct 12, 2017 7:03 pm

you can also swap on a regular egr valve like earlier models.
that’s what I did on my ‘90 because here in CA have to have it for testing.
mine is actually disabled, but it has to @ least look good lol
@ that time the late model valve was unobtainable, not that I’d spend $100 on on anyway.
-Tony
'88 GW (aka Babywag) '90 GW (aka JunkBucket) both fuel injected.

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derf
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Re: Installed New cat, should I hook the exhaust return up or no ?

Postby derf » Thu Oct 12, 2017 9:52 pm

The little pipe is there for the air pump to push fresh air into the cat when it's not pushing air in at the manifolds. If you don't have an air pump, you should leave it capped.
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candymancan
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Re: Installed New cat, should I hook the exhaust return up or no ?

Postby candymancan » Thu Oct 12, 2017 10:41 pm

So how do i adjust the vacuum advance if you think thays the issue ?

Also what does the air pump do exactly ? I thought it had something to do with the egr ? I only have one manifold with tubes coming out.. The other manifold doesnt have them..

Why does the air pump push air into the cat ? what does that accomplish ? Im reading if i dont hook it up to my cat it can damage my catalytic convertor.. Maybe i shouldnt have ordered one with the pipe lol ?

So if i remove the airpump.. What tubing and everything else can i remove to clean up the engine bay a little. Why does it push air into the manifolds ? I assume to keep them colder ?
2013 SS camaro, cammed, and modded too much to say 500 RWHP 30k
1998 Jeep Grand Cherokee 5.9L Limited 181k
1998 Jeep Grand Cherokee 4.0 I6 laredo 240k
1990 Jeep Grand Wagoneer 116k

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babywag
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Joined: Fri Jun 08, 2012 7:29 pm
Location: Land of Fruit Loops & Coconuts

Re: Installed New cat, should I hook the exhaust return up or no ?

Postby babywag » Fri Oct 13, 2017 9:49 am

back in 80’s & 90’s cats were crude and inefficient. The needed air pumps to help start the reaction get going.
most modern cats do not need this.

all the air pump crap can go in trash
none of it is needed if local regs will allow removal.
-Tony
'88 GW (aka Babywag) '90 GW (aka JunkBucket) both fuel injected.

candymancan
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Joined: Tue Mar 22, 2016 11:32 pm

Re: Installed New cat, should I hook the exhaust return up or no ?

Postby candymancan » Fri Oct 13, 2017 2:00 pm

Yea looking at the manifold that doesnt have the tubes. i can see someone welded them shut at the bolts. Perhaps it rusted through the tuny tubes so they deleted that half. I guess i'll remove it and weld the other manifold bolts.

You positive though ? Because if the magnaflow has the tube then wouldnt it need it to complete the reaction at least thats what i keep reading. I just dont wanna destroy my cat in a yea or whatever.

What do i do with the smaller vacuum lines on the air pump stuff ? Obviously remove the large tubes, and the pump itself, but there are a couple vacuum lines on it. Do i just cut them short and plug them ? Looks like some of them go to CTO's or something
2013 SS camaro, cammed, and modded too much to say 500 RWHP 30k
1998 Jeep Grand Cherokee 5.9L Limited 181k
1998 Jeep Grand Cherokee 4.0 I6 laredo 240k
1990 Jeep Grand Wagoneer 116k

candymancan
Posts: 1305
Joined: Tue Mar 22, 2016 11:32 pm

Re: Installed New cat, should I hook the exhaust return up or no ?

Postby candymancan » Sat Oct 14, 2017 5:56 pm

Is it normal for a new cat to smell like fireworks ? It been smelling like gun powder for a few days..
2013 SS camaro, cammed, and modded too much to say 500 RWHP 30k
1998 Jeep Grand Cherokee 5.9L Limited 181k
1998 Jeep Grand Cherokee 4.0 I6 laredo 240k
1990 Jeep Grand Wagoneer 116k

candymancan
Posts: 1305
Joined: Tue Mar 22, 2016 11:32 pm

Re: Installed New cat, should I hook the exhaust return up or no ?

Postby candymancan » Mon Oct 16, 2017 10:48 pm

bump.. can someone tell me why the exhaust smells like gun powder or sulfur i guess.. Been a week now and smell isnt really going away.
2013 SS camaro, cammed, and modded too much to say 500 RWHP 30k
1998 Jeep Grand Cherokee 5.9L Limited 181k
1998 Jeep Grand Cherokee 4.0 I6 laredo 240k
1990 Jeep Grand Wagoneer 116k


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