Catalytic and 02 sensor question

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Dec 1, 2011 | 06:56 PM

true blue

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Joined: Mar 2002

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From: Huntsville, Alabama

Catalytic and 02 sensor question

I bought my 2002 6.8 V10 4X4 with 155K miles without a catalytic converter. It was removed and a Flowmaster installed by the previous (young) owner. I wish to reinstall a Cat. The largest reason is because of the smell of the exhaust. It smells rich. Smells like an old truck of lore (Not oil burnning). The truck runs perfectly. This leads me to some questions.

1. Is the Cat out of a 5.4 truck the same as the 6.8?

2. Is it normal to smell rich w/o a cat?

3. I do not have a CEL but would replacing the 02 sensors cure some of the smell?

4. I would have to find a way to evaluate the fuel to air ratio but would a programmer cure the rich smell w/o burning a hole in the pistons or burning a valve?

Dec 1, 2011 | 07:26 PM

IslandBlueV10

Senior User

Joined: May 2010

Posts: 471

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From: Pocatello, Idaho

Hello, when I bought my truck it was the same thing no cat. My truck smelled the same way, I hated it in the summer when having the windows down. I ended up buying a Magna flow high flow cat. It cost around $140, and cost $40 to have welded on. So far it has worked well, and no more smell.

Performance wise I didn't notice any change.

Dec 1, 2011 | 07:31 PM

truckinforever

Freshman User

Joined: Aug 2011

Posts: 35

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From: Pageland, SC

I have a 03 v10 with no cat and it smells rich even with a tuner. That's the way most engines smell without the cat installed. Go to link and buy this. I used it in my 87 302 merc w/o cat and it made it smell great. There's 19 different fragrances. Manhattan Oil 19769-45 - Manhattan Oil Fuel Fragrances - Overview - SummitRacing.com

Dec 2, 2011 | 07:43 AM

true blue

Thread Starter

Elder User

Joined: Mar 2002

Posts: 549

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From: Huntsville, Alabama

Quote:

Originally Posted by truckinforever

There's 19 different fragrances. Manhattan Oil 19769-45 - Manhattan Oil Fuel Fragrances - Overview - SummitRacing.com

Wow, never heard of that. Yeah I might try a bottle just for the fun of it but I think I will go with the suggestion from IslandBlue.

Thanks!

Dec 2, 2011 | 07:59 AM

dkf

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Joined: Mar 2007

Posts: 10,101

Likes: 40

From: Pa

Answers in red.

1. Is the Cat out of a 5.4 truck the same as the 6.8?

On the 99-04 trucks, yes as far as I know. An OEM replacement cat will cost you an arm and leg. If you want to put a cat on a properly sized universal cat will work fine and cost a lot less money.

2. Is it normal to smell rich w/o a cat?

Yes.

3. I do not have a CEL but would replacing the 02 sensors cure some of the smell?

No. You probably have no O2 sensor after the cat which is why you have no CEL.

4. I would have to find a way to evaluate the fuel to air ratio but would a programmer cure the rich smell w/o burning a hole in the pistons or burning a valve?

A tuner will not help. A good tune will run stoich during normal driving and then add fuel during WOT and heavier loads. The stock tune runs stoich all the time and does not have WOT fuel enrichment. So the tune basically adds more fuel where its needed to make more power safer.

Dec 2, 2011 | 10:08 AM

SuperDutyScaler

Lead Driver

Joined: Nov 2008

Posts: 8,450

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From: South Jersey

this is the biggest universal cat i found that can handle the motor and GVW of a Ford SD. I have a magnaflow "highflow" on my 5.4 and it sucks! in the summer you hear it crackle and if i tow something heavy you smell converter. I should have kept the stock cat but at 20 years old i wanted that sound, now at 26 i want my stock cat back!

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