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Exhaust Smell During Acceleration

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exhaust
33K views 41 replies 26 participants last post by  Jlrjrr8 
#1 ·
2014 5.7L Overland has a strong exhaust smell during hard acceleration. The dealer has replaced the drivers side exhaust manifold bolts (sheared off). The smell continued and then the mechanic said my parking break was on; didn't correct the smell.

It appears this is common problem but I haven't found a solution on this site or any others.

Anybody know what going on? Bad Cat? Emissions control?

Thanks,
 
#4 ·
I think it's something to do with the fuels these days and the catalytic converters. I seem to get that as well only during hard acceleration in my 2015 V6. Even my Corvette does it. I only use top tier fuels as well so who knows. It's normal as far as I'm concerned.
 
#12 ·
I had this problem BAD on my 2005 Toyota 4Runner. Less so on my 2012 and 2015 V8 Overlands, but it is still present. :(

I believe it has a lot to do with how hard you push it regularly and what fuel you use. Interestingly, it get better when I drive in Sport Mode and use my paddle shifters. :confused:

And the main cause are current clean air regulations, emissions controls & catalytic converters.
 
#14 ·
I have a 2012 Limited 5.7L and have owned it since June 2016. I have smelled this exhaust smell coming from the back after several seconds following hard acceleration all the time. It doesn't matter if the windows are closed, open, AC on with inside circulating on or off. I decided to track down exactly where it's coming from so I had my 13 year old daughter get into the back area and identify where the smell was coming from as I got on the gas. She said it was coming from the louvered vent at the very back of the vehicle and only from the driver side one as there's 2 vents back there. If you look through the louvers you can see the metal body of the car and there's 3 holes right behind the louvers. I think this is part of an air circulating system that allows outside air to enter the vehicle from the back near the ground. Unfortunately this region outside the car also can experience exhaust coming in when the vehicle is in motion and when under heavy acceleration and when under heavy acceleration the exhaust gets "smelly" from lots of fuel being burned and depending on the state of the cats could also smell like sulphur too. I had thought of pulling that inside panel off that has the louver on the driver side and cover up these body holes with Gorilla brand duct tape and see if this remedies this problem. I just haven't gotten around to ripping apart the rear panels to try this idea out but at least I know where it's coming from. I also don't know how the dealer would be able to fix this other than altering the design of the car and this air system.
 
#15 · (Edited)
I wouldn't cover the holes. Sounds like a bandaid for the real problem.

I had a 2012 Summit with the V8 and never had this problem. Sounds like an exhaust leak of some sort. It doesn't make sense that you would get that smell from the rear of the vehicle either as the exhaust coming out there is the "cleanest"

Sounds like there is an exhaust leak pre-catalyst. I had loose header bolts on my motocycle that caused this exact problem. I would check for loose bolts upstream of the cats.

The vent(s) is there to equalize pressure in the vehicle when the windows are down or the moonroof is open.

Unintended consequences are hard to close doors and screwing with how the air con works, not to mention your ears popping.
 
#18 ·
I have the same issue, ‘17 Overland. Under hard acceleration entering the freeway, I’ll get heavy fumes in the cabin. The dealer is giving me the run around like they have no idea what I’m talking about even though they admitted it exists. I’m guessing Jeep is very aware of it but the don’t want to fix it.
 
#21 ·
My 18' does this when WOT. The smell comes about a min after I let go of the gas.


I figure its either poor quality winter gas or an exhaust leak around the cat.


Ill have the dealer take a look, but its nothing damaging. I do have a borla catback, but I didnt see any leaking fumes on a cold start coming from under the car, even when free revving.



Its only when hitting it hard on the street.
 
#24 ·
I'm still dealing with this problem and have just learned to accept it.:(

I just know if I'm going over 40 and get on it I'll have to roll the windows down and ride a bit to air out the cabin!
Hi Vanguard and atvmax,
We understand why this may be concerning. If you decide to have your dealers look into this, you may also send us a private message so we can have this documented escalated for further handling.
Lydia
Jeep Social Care Specialist
 
#27 ·
Hi, Guys! I face the same problem with my 2015 Grand Cherokee Limited 3,6L. Since I bought it in 2017, I have complained about this problem at Jeep Store here in Brazil, but they tell that there are not leaks. But every full acceleration on the road, the smell comes inside. I guess that owners who lives in USA could dennounce it to a regulatory agency, to compel Jeep to make a world recall.
 
#28 ·
I had the same issue with my 2019 JL, when accelerating hard an exhaust odor will come from the A/C vents. My fix was the flange that connects the exhaust piping to the head had slack bolts from factory. Mind the JL 3.6 engine doesn’t have a traditional exhaust manifold. It appears like the exhaust piping flanges straight to the head.
 
#29 ·
If you get under the rear of the Jeep, there is a flap on both sides, between the rear wheel well and the rear bumper. You have to look close to see it. Make sure it lays flat against the opening. I believe the flaps are there to equalize cabin pressure while closing the doors and moving with the sun roof or windows open. On my 1996 GC these vents were located on the rearmost pillar between the rear side glass and the rear lift gate. Seems like it was a better design than the present.
 
#34 ·
I haven't experienced this....yet! That i can tell.
My hunch it has to do with that dam rear wing over the tailgate sucking up road dust, snow and rain onto the rear hatch and yes maybe even exhaust fumes being sucked up possibly into the rear vents.
Could be the reason some other SUV's many of them these days use that dam rear wing over the hatch.

Now i rarely use AC only in the hottest days, never use re-circ, auto climate, etc. but like to keep at least one window cracked open in the Winter and Summer with AC or heat for fresh cabin air.
That open window possibly could provide a negative cabin pressure to vacuum out any exhaust fumes entering the cabin.
That could be the reason i've never experienced this or my sniffer is working so good these days.
Right or wrong, just IMO.

In case some of you reading this thread haven't heard my opinion of that that dam dust, snow, grime and rain collecting wing on the hatch......
I hate that dam thing and if i intend to keep my WK2, i'm gonna remove that F'ing thing once and for all.
 
#35 ·
I think Adburger answered the question. These vents are to exhaust air - not let it in. They create a negative pressure in the cabin so that conditioned air from the climate control can enter easily. They also help with buffeting from the windows and let pressure escape when you close a door. There should be one-way flaps that let the air out but prevent air from coming in. The flaps could be damaged or obstructed with debris.
 
#36 ·
That negative air pressure pulling exhaust, dirt, sand, dust, rain and snow onto the rear hatch is created by the wing over the hatch.
That wing is the root cause and IMO should be jettisoned for any future Jeeps.
Alas other car mfger's including foreign cars use that wing.
Monkey see monkey do.

This exhaust smell has never been an issue until the wing above the rear hatch appeared.
I suspect its there to add a tiny bit of fuel mileage by creating a negative pressure under the vehicle's exhaust system and other obstructions under the vehicle.
 
#37 ·
In addition to what i mentioned above ^, the hatch seals might not be sealing 100% allowing the vacuum caused by the above rear hatch wing to suck up exhaust fumes into the cabin.

For any non believer's out there that don't think that F'n hatch wing will suck up anything and every thing from the road including exhaust fumes and deposit it on the hatch....... on a cold day when just starting out look into rear view mirror and watch the exhaust being sucked upwards across the hatch.
 
#38 ·
I have a 2019 Grand Cherokee Limited and am having the same issue with a smokey/exhaust smell coming into the cabin after hard acceleration.

I am planning on bringing the car to the dealer next week, but curious if anyone has any experience with locating/replacing the rear quarter panel exhausters that were previously mentioned? If I am able to see if the exhausters are damaged or clogged, I'll replace them to see if the problem improves.

Below is the link to the OEM exhausters in case anyone is interested.

2008-2021 Mopar Quarter Panel Exhauster 68260545AA | Mopar Estores
 
#40 ·
I ended up having both of the rear exhausters replaced and it solved the problem. The dealership had never heard of the issue before, but Jeep Engineering concurred that the exhausters were the likely issue.

When the dealer went in to replace the exhauster vents, they found that one had completely fallen out and the other wasn’t making a good seal. Seems like a bad installation at the factory.
 
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