Bad smell after replacing the catalytic converters?

Tiny
WILLIE HURLOCKER
  • MEMBER
  • 2005 DODGE MAGNUM
  • 5.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 134,000 MILES
Hey brother back again! Got to quit meeting like this! Okay, I've got new cats just changed the fluid and filter on the transmission and also I had #2 spark plug under oil. So, I replaced both sides O-rings and valve cover gaskets, no leaks on the gaskets but there is a leak on the transmission gasket. No codes as of yet. Its been a day about 30 miles. Do you think it could be the EGR valve making it run lean or transmission getting hot? It shifts great up/down shifting and if it were the transmission it would go into limp mode, correct? Oh, yea topped of the rear pumpkin, which I'm still getting that cracking/popping sound at low speeds? Hopefully you guys can help me out quickly. My mom has a doctors appt. Coming up soon, I appreciate it. Can't film the smell sorry!
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Wednesday, July 26th, 2023 AT 7:55 PM

19 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,114 POSTS
Hi,

How would you best describe the smell? Does it have a rotten egg smell or something different? Also, if the converters are new with only 30 miles on them, the smell may go away after a few more miles.

As far as the transmission running hot, that wouldn't cause a lean fuel mixture. On the other hand, a faulty EGR can. Are you sure it is running lean? I ask because there are presently no codes.

Let me know if you have a live data scan tool. If you do, let me know what the short-term fuel trims are when the engine is at operating temp.

Also, here is a link that explains how to locate and repair a vacuum leak. If you have a leak, it will cause a lean mixture.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know as much as you can.

Take care,

Joe
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Thursday, July 27th, 2023 AT 9:56 PM
Tiny
WILLIE HURLOCKER
  • MEMBER
  • 83 POSTS
Hey Joe,

SHRTFTB2S2(%) 99.2
SHRTFTB1S1(%)-1.6
SHRTFB1S2(%)N/A
SHRTFT1(%)-5.5
SHRTFT2(%)-4.7

Yesterday I was under the hood and heard a loud air release like a big truck does letting air off the brakes, not as loud but loud! No codes. It came from drivers' side almost sounded like the intake gasket. I sprayed carb cleaner around and did not disrupt the idle at all? Earlier today I got into traffic and had to get over but someone wouldn't let me. So, I gave her a little shove and she hiccupped but went! Also, yesterday I was checking for vacuum leaks and she just quit running, started back up no problem, but she did it again a little later but started right back up? She's not getting hot have bad MPGs though. About 2 MPG less than usual. I recently replaced the valve cover gaskets and plug o-rings because # 2 plug was under oil in the well. A couple times I've smelt bad smell like the cats were clogged but they are new. I did get codes last week for P2096 and PO153. They haven't come back yet. Thanks Joe.
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Friday, July 28th, 2023 AT 10:33 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,114 POSTS
Hi,

Is the STFT (B2S2) reading in pic 2 accurate? If that is, a significant vacuum leak in the intake system can result in unmetered air entering the engine. Also, a malfunctioning MAF sensor might provide incorrect readings of the incoming air, leading to improper fuel delivery and extremely positive fuel trim values or the fuel pressure regulator has failed.

The P2096 is specific to a lean fuel mixture. So, I attached the diagnostics below specific to the code and your vehicle. You mentioned the converters are new. Are there any exhaust leaks pre-catalytic converter? Let me know.

Take a look through the diagnostics below and let me know if you are comfortable performing them.

Take care,

Joe

See pics below.
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+1
Friday, July 28th, 2023 AT 7:31 PM
Tiny
WILLIE HURLOCKER
  • MEMBER
  • 83 POSTS
There is an exhaust leak but it's not after the downstream, it's at the flange between the o2s! I changed the purge valve. It seems to be doing good, for now. It runs really good, real responsive throttle. Better than it has ever been without a tune. I noticed on one of the parameters for the shrtft it had N/A, what's that about? It has always been like that, is it normal?
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Friday, July 28th, 2023 AT 7:49 PM
Tiny
WILLIE HURLOCKER
  • MEMBER
  • 83 POSTS
No MAF sensor on the wagon! There's a MAP.
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Friday, July 28th, 2023 AT 7:52 PM
Tiny
WILLIE HURLOCKER
  • MEMBER
  • 83 POSTS
No MAF sensor on the wagon! There's a MAP. Shouldn't it have thrown a code by now? When I took those pics I drove about 15 miles before.
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Friday, July 28th, 2023 AT 8:02 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Where is the exhaust leak? Is it before the downstream sensor?

Joe
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Friday, July 28th, 2023 AT 10:21 PM
Tiny
WILLIE HURLOCKER
  • MEMBER
  • 83 POSTS
Yes, between the up and down at the flange pretty sure on both sides.
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Friday, July 28th, 2023 AT 11:45 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,114 POSTS
That is the likely cause of the lean fuel mixture. If you have an exhaust leak before the sensor, air enters (believe it or not) and the sensor sees it as a lean mixture.

I'm not sure what needs to be repaired, but that is where I would suggest starting. Let me know if I can help.

Take care,

Joe
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Saturday, July 29th, 2023 AT 8:18 PM
Tiny
WILLIE HURLOCKER
  • MEMBER
  • 83 POSTS
You need my add? Let me know before you arrive my dogs will eat you!
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Saturday, July 29th, 2023 AT 9:39 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,114 POSTS
LOL I'm a dog lover, but that doesn't sound too inviting. LOL

Take care and let me know what you find.

Joe
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Saturday, July 29th, 2023 AT 10:59 PM
Tiny
WILLIE HURLOCKER
  • MEMBER
  • 83 POSTS
I'm still getting that cracking/popping sound at slow speeds? I re-torqued everything in the rearend checked fluid new wheel bearings and axle shafts, what's left?
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Sunday, July 30th, 2023 AT 11:05 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

When you replaced the rear drive shaft, was it with a new one? I ask because the rear drive shaft service is limited to center support bearing and coupler replacement only. The rear segment single-cardan universal joint is not serviceable.

Did you replace the center support bearing? See pic below.

Also, if the noise is loud enough to record, do so and upload it for me to hear.

Take care,

Joe

See pic below.
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Sunday, July 30th, 2023 AT 8:37 PM
Tiny
WILLIE HURLOCKER
  • MEMBER
  • 83 POSTS
The flex disks and drive shaft I replaced are new so it's not the u joint also carrier bearing. There is slack in the rearend yoke, think that could make the sound? I've sent audio before, but I'll try to send more. I also marked the shaft before taking it off but it was pointless because it was all new. There is no vigratn at all so for once I got something right somehow the first time. The car rides really rough and hard like I'm rolling on just the rims with no tires on?
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Monday, July 31st, 2023 AT 7:15 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,114 POSTS
Hi,

As far as the rough ride, are there any suspension issues? Have there been any modifications to the suspension? Also, the noise you described is likely a bearing in the differential. The pinion bearing would be my first suspect. Do you have any gear oil leaking where the pinion seal is located?

Let me know.

Joe
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Monday, July 31st, 2023 AT 9:17 PM
Tiny
WILLIE HURLOCKER
  • MEMBER
  • 83 POSTS
Is there supposed to be this much play?
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Tuesday, August 1st, 2023 AT 2:27 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,114 POSTS
Hi,

In a perfect world, there shouldn't be that much play. It is a bit excessive. I assume I am looking at the rear pinion shaft. It's a little hard to see in the video. That play is taken up when the ring and pinion are installed. Adjustment is made at that point.
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Tuesday, August 1st, 2023 AT 7:38 PM
Tiny
WILLIE HURLOCKER
  • MEMBER
  • 83 POSTS
How do I take up the slack? Is it difficult or what's a fair price to have it done? I'll try to remember to get you audio and video tomorrow! The exhaust leak I'm pretty sure it at the flange coming off the manifold. There's no codes only the BAS/ESP light?
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Tuesday, August 1st, 2023 AT 8:41 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,114 POSTS
Hi,

The differential needs to be taken apart. There are two carrier bearings, one on each side. Those are adjustable. Those are used to place the ring gear in the correct position. The pinion shaft/gear is adjusted with shims.

If you need to have it done, I would expect someone to charge for around 5 hours because if the shims need to be added, you have to remove the shaft/gear and start over.

Joe
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Wednesday, August 2nd, 2023 AT 5:26 PM

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