Bad or Burnt Exhaust smell in cabin during hard acceleration.

[CommandPresence]

As my problem is still present, today I actually installed a CO detector in the back of my Explorer. See here: http://www.explorerforum.com/forums...orer-carbon-monoxide-detector-install.462965/

 

[Jon M]

OK, so after dropping my '13 off today for this issue, I've spent the day thinking about it. I've read a lot of this thread, but Ford will have a fix before I can wade through 93 pages, so...

I saw it asked, but never saw it answered; is it only the 3.5L engines that have this issue? Not the 4 cylinders?

I was talking to a friend about the issue. Neither of us are engineers, nor are we ASE certified mechanics, nor Ford experts. That said, we independently came to the same point, which is that there's no way that this is coming from the rear of the vehicle. I won't say it's impossible, but certainly highly improbable. I would hope that people at Ford have considered these things, but since this is the direction they're moving, I have my doubts.

Consider that the majority report only noticing the smell at WOT. That means the vehicle is moving, and accelerating, so there is wind blowing front to back. That being the case, how, short of magically overcoming the laws of physics, is the Explorer sucking exhaust fumes in from the back?!? Somehow, the exhaust is exiting the tail pipe, and despite all of the wind blowing in the opposite direction, that exhaust is being pulled forward into the cabin? At 60+ mph, in my case? I just don't buy it. Ever blown cigarette smoke out the window of a moving car? How is it being pulled forward? It's not.

My friend and I both said 'it has to be coming from forward of the firewall'. That's the only way we could be smelling it in the front seat, while running WOT. So, looking at it from that perspective, where is it really coming from?

I have three ideas, and it could be any one, or a combination, and these would explain why it happens to some, but not others.

First, is a leaking exhaust gasket. If, like many, Ford uses multiple suppliers for gaskets, and one of those suppliers is using an "acceptable", but slightly different material for the gasket, that gasket might not be holding up under higher temperature and/or pressure.

Second, and potentially related, is inadequate torque on the bolts in the exhaust, from the manifolds back. Torque is generally spec'd in a range. If the lower end of that range is actually not sufficient to maintain the seal, or in combination with an inadequate gasket, the lower end of the spec doesn't completely seal it, that could allow exhaust to leak under limited circumstances, again of higher temp/pressure.

Last, is faulty welds in the exhaust. It would only need to be a small one, in a hard to find spot, or worse, in any of several hard to find spots, to allow this to happen.

If this is only happening on the V-6s, that would add a little weight to these ideas, as the 4 cylinders would have different manifolds, gaskets, etc.

With the current "fix", they're sealing the body seams. Maybe that needs to be done up front to, or instead. Or it's coming in somewhere else up front, and the recirculate thing is just pushing it further into the cabin, faster, because it's leaking in somewhere on the front floor, where that recirc air is being picked up.

My personal experience has been that the hotter it is outside, and therefore the hotter the vehicle, the worse the odor. When it's over 90, it comes in heavy, recirc or not.

It seems like there has to be some sort of sniffer that could figure out if there is a small leak up front. I know someone mentioned contacting a lab, back in the first 15(?) pages, but I didn't see what came of it, if anything.

Thoughts?

 

[CommandPresence]

OK, so after dropping my '13 off today for this issue, I've spent the day thinking about it. I've read a lot of this thread, but Ford will have a fix before I can wade through 93 pages, so...

I saw it asked, but never saw it answered; is it only the 3.5L engines that have this issue? Not the 4 cylinders?

I was talking to a friend about the issue. Neither of us are engineers, nor are we ASE certified mechanics, nor Ford experts. That said, we independently came to the same point, which is that there's no way that this is coming from the rear of the vehicle. I won't say it's impossible, but certainly highly improbable. I would hope that people at Ford have considered these things, but since this is the direction they're moving, I have my doubts.

Consider that the majority report only noticing the smell at WOT. That means the vehicle is moving, and accelerating, so there is wind blowing front to back. That being the case, how, short of magically overcoming the laws of physics, is the Explorer sucking exhaust fumes in from the back?!? Somehow, the exhaust is exiting the tail pipe, and despite all of the wind blowing in the opposite direction, that exhaust is being pulled forward into the cabin? At 60+ mph, in my case? I just don't buy it. Ever blown cigarette smoke out the window of a moving car? How is it being pulled forward? It's not.

My friend and I both said 'it has to be coming from forward of the firewall'. That's the only way we could be smelling it in the front seat, while running WOT. So, looking at it from that perspective, where is it really coming from?

I have three ideas, and it could be any one, or a combination, and these would explain why it happens to some, but not others.

First, is a leaking exhaust gasket. If, like many, Ford uses multiple suppliers for gaskets, and one of those suppliers is using an "acceptable", but slightly different material for the gasket, that gasket might not be holding up under higher temperature and/or pressure.

Second, and potentially related, is inadequate torque on the bolts in the exhaust, from the manifolds back. Torque is generally spec'd in a range. If the lower end of that range is actually not sufficient to maintain the seal, or in combination with an inadequate gasket, the lower end of the spec doesn't completely seal it, that could allow exhaust to leak under limited circumstances, again of higher temp/pressure.

Last, is faulty welds in the exhaust. It would only need to be a small one, in a hard to find spot, or worse, in any of several hard to find spots, to allow this to happen.

If this is only happening on the V-6s, that would add a little weight to these ideas, as the 4 cylinders would have different manifolds, gaskets, etc.

With the current "fix", they're sealing the body seams. Maybe that needs to be done up front to, or instead. Or it's coming in somewhere else up front, and the recirculate thing is just pushing it further into the cabin, faster, because it's leaking in somewhere on the front floor, where that recirc air is being picked up.

My personal experience has been that the hotter it is outside, and therefore the hotter the vehicle, the worse the odor. When it's over 90, it comes in heavy, recirc or not.

It seems like there has to be some sort of sniffer that could figure out if there is a small leak up front. I know someone mentioned contacting a lab, back in the first 15(?) pages, but I didn't see what came of it, if anything.

Thoughts?

Jon,
I'm with you on the logic above. I'll catch up with you via messaging to discuss.

 

[Black Eyed]

OK, so after dropping my '13 off today for this issue, I've spent the day thinking about it. I've read a lot of this thread, but Ford will have a fix before I can wade through 93 pages, so...

I saw it asked, but never saw it answered; is it only the 3.5L engines that have this issue? Not the 4 cylinders?

I was talking to a friend about the issue. Neither of us are engineers, nor are we ASE certified mechanics, nor Ford experts. That said, we independently came to the same point, which is that there's no way that this is coming from the rear of the vehicle. I won't say it's impossible, but certainly highly improbable. I would hope that people at Ford have considered these things, but since this is the direction they're moving, I have my doubts.

Consider that the majority report only noticing the smell at WOT. That means the vehicle is moving, and accelerating, so there is wind blowing front to back. That being the case, how, short of magically overcoming the laws of physics, is the Explorer sucking exhaust fumes in from the back?!? Somehow, the exhaust is exiting the tail pipe, and despite all of the wind blowing in the opposite direction, that exhaust is being pulled forward into the cabin? At 60+ mph, in my case? I just don't buy it. Ever blown cigarette smoke out the window of a moving car? How is it being pulled forward? It's not.

My friend and I both said 'it has to be coming from forward of the firewall'. That's the only way we could be smelling it in the front seat, while running WOT. So, looking at it from that perspective, where is it really coming from?

I have three ideas, and it could be any one, or a combination, and these would explain why it happens to some, but not others.

First, is a leaking exhaust gasket. If, like many, Ford uses multiple suppliers for gaskets, and one of those suppliers is using an "acceptable", but slightly different material for the gasket, that gasket might not be holding up under higher temperature and/or pressure.

Second, and potentially related, is inadequate torque on the bolts in the exhaust, from the manifolds back. Torque is generally spec'd in a range. If the lower end of that range is actually not sufficient to maintain the seal, or in combination with an inadequate gasket, the lower end of the spec doesn't completely seal it, that could allow exhaust to leak under limited circumstances, again of higher temp/pressure.

Last, is faulty welds in the exhaust. It would only need to be a small one, in a hard to find spot, or worse, in any of several hard to find spots, to allow this to happen.

If this is only happening on the V-6s, that would add a little weight to these ideas, as the 4 cylinders would have different manifolds, gaskets, etc.

With the current "fix", they're sealing the body seams. Maybe that needs to be done up front to, or instead. Or it's coming in somewhere else up front, and the recirculate thing is just pushing it further into the cabin, faster, because it's leaking in somewhere on the front floor, where that recirc air is being picked up.

My personal experience has been that the hotter it is outside, and therefore the hotter the vehicle, the worse the odor. When it's over 90, it comes in heavy, recirc or not.

It seems like there has to be some sort of sniffer that could figure out if there is a small leak up front. I know someone mentioned contacting a lab, back in the first 15(?) pages, but I didn't see what came of it, if anything.

Thoughts?

After the latest fix with changing the exhaust to make the flow towards down, there is a big deference but the smell still there.

i did some additional sealing on the back door to make sure there is no leaking point but also the smell is there.

i believe the smell also finds a way to leak inside from the front " fresh air intake"

since the cat converters is located right next to the engine i think they are our main issue.

i have noticed after every long drive when i go out of the car i immediately smell the same smell from the sides, if i come closer to the front tiers the smell gets stronger. which prove it's a cat converters issue.

i don't know why ford designers put the cat converters is such location , should be right beneath the car like most of the cars, easy to change also will not cause extra heat to the engine room.

i think the best way to fix this issue to change the entire exhaust system from the engine to the end back and relocate the cats to be beneath the car.

also ford needs to check the front a\c fresh air intake this is also may cause the issue.

 

[peterk9]

OK, so after dropping my '13 off today for this issue, I've spent the day thinking about it. I've read a lot of this thread, but Ford will have a fix before I can wade through 93 pages, so...

I saw it asked, but never saw it answered; is it only the 3.5L engines that have this issue? Not the 4 cylinders?

I was talking to a friend about the issue. Neither of us are engineers, nor are we ASE certified mechanics, nor Ford experts. That said, we independently came to the same point, which is that there's no way that this is coming from the rear of the vehicle. I won't say it's impossible, but certainly highly improbable. I would hope that people at Ford have considered these things, but since this is the direction they're moving, I have my doubts.

Consider that the majority report only noticing the smell at WOT. That means the vehicle is moving, and accelerating, so there is wind blowing front to back. That being the case, how, short of magically overcoming the laws of physics, is the Explorer sucking exhaust fumes in from the back?!? Somehow, the exhaust is exiting the tail pipe, and despite all of the wind blowing in the opposite direction, that exhaust is being pulled forward into the cabin? At 60+ mph, in my case? I just don't buy it. Ever blown cigarette smoke out the window of a moving car? How is it being pulled forward? It's not. ........................................................................

Thoughts?

I believe it is certainly probable that it is coming from the rear and that the faster you drive the more likely it is to add to the issue. The answer is 'air flow'. The air flow over the vehicle, especially an SUV, creates something similar to a vacuum behind it and that is why it is virtually impossible to keep the rear of an SUV clean for any length of time. It is somewhat similar to an aircraft's wing. The air flowing over the top moves faster than the air under it thus creating 'lift'. In our case, the 'lift' would pull exhaust gases up with it. You can sometimes see it in the Winter when a travelling car's exhaust seems to create a small swirling cloud behind it.

Peter

 

[Jon M]

I believe it is certainly probable that it is coming from the rear and that the faster you drive the more likely it is to add to the issue. The answer is 'air flow'. The air flow over the vehicle, especially an SUV, creates something similar to a vacuum behind it and that is why it is virtually impossible to keep the rear of an SUV clean for any length of time. It is somewhat similar to an aircraft's wing. The air flowing over the top moves faster than the air under it thus creating 'lift'. In our case, the 'lift' would pull exhaust gases up with it. You can sometimes see it in the Winter when a travelling car's exhaust seems to create a small swirling cloud behind it.

Peter

It would still require a significant negative air pressure to suck it into the cabin. There's a difference between depositing airborne dirt on the back and entering the cabin. If it was just a matter of inadequate seal on the tailgate, perhaps, but that's part of the TSB and it's not solving it. For it to be pulling back under, and then up through the seams, or through the vent on the left rear, would be quite a feat, especially working against the HVAC flow that would be pushing it back out. Then, it also has to pull it all the way up to the front of the cabin, again against air flow pushing from the front vents towards the back.

Recirculate pulls air from the front floor, so it has to be making it up there. It happens with the rear A/C on, pushing down from above. Without recirc on, it still does it, and most of the early complaints said that recirc made it better, not worse. Somewhere along the way that either changed, or was twisted into it happening with it on. So you've got fresh air pushing backward, rear A/C being directed down, and somehow it's still pulling it from outside, at highway speed, to the front of the cabin? How much negative air pressure would that require, and how much is actually being generated?

My doubts persist. Certainly, if it were coming from the back, sealing the seams and tightening the seal on the tailgate would be enough to counter it, when factoring in the air flow inside, and would greatly reduce the ability of any negative pressure to pull it into the cabin.

And, if we assume that Ford is correct, and it is coming from the rear, and their existing fixes aren't enough, then they're missing out on possible entry points at the three windows in the cargo area and tailgate, along with other seams further up. That would require a much more significant disassembly to seal.

 

[peterk9]

All good points Jon. I still find it odd that not all Explorers have this issue. Although I don't find a need to use WOT much, especially with the Ecoboost, I have used it on both my 2011 and 2017 without any problems.

 

[blwnsmoke]

Jon, living up in NH, I see a winter long then when I go WOT, the exhaust fumes completely covers the rear window to the point that I can't see through it (when the exhaust looks white from the cold temps). The fact that the fumes in the winter (same in summer but can't see it) completely engulf the rear end, I can totally see how it can enter inside from the rear.

I am not saying that it is the problem but I can see how it could. On top of that, having a rear HVAC system in the rear bumper.. well It is possible.

 

[Jon M]

All good points Jon. I still find it odd that not all Explorers have this issue. Although I don't find a need to use WOT much, especially with the Ecoboost, I have used it on both my 2011 and 2017 without any problems.

If my theory of it being a gasket and/or torque issue is correct, it would only apply to vehicle with gaskets from that supplier, and/or bolts torqued to the lower end of the range.

Jon, living up in NH, I see a winter long then when I go WOT, the exhaust fumes completely covers the rear window to the point that I can't see through it (when the exhaust looks white from the cold temps). The fact that the fumes in the winter (same in summer but can't see it) completely engulf the rear end, I can totally see how it can enter inside from the rear.

I am not saying that it is the problem but I can see how it could. On top of that, having a rear HVAC system in the rear bumper.. well It is possible.

I can see that, but if it were the case, then the reports would be that it's prominent with the rear A/C on, which isn't the case. I experimented with mine in every configuration of HVAC, and found that the rear A/C doesn't have an effect, so at least for mine, the idea of it coming in from the rear seems less likely.

I just bought a multi-gas detector, that will pick up on CO and exhaust gasses. When I get it back from the dealer, I'm going to poke around with it in the engine compartment, and underneath, to see if there are any leaks. The one I bought has a "geiger counter" like operation, where it beeps faster as it gets closer to the source.

While I was typing this, I got a call from the dealer, saying they verified the concern, but it's not covered under my ESP! I'm going to be calling Ford now.

So, apparently the Ford "contact center" doesn't know what they're talking about. They told me they agreed with the dealer that this wouldn't be covered under my ESP, and when I asked to speak to the Customer Service Manager for the area, told me they don't have their contact info. Seriously?

I called the dealer back and told the service adviser I wanted to speak to the area manager. She just called back to tell me that she spoke to the service manager for the dealer, and that she was wrong, it is covered by the ESP. She's new-ish and still learning the Ford stuff.

 

[Sixonemale]

If my theory of it being a gasket and/or torque issue is correct, it would only apply to vehicle with gaskets from that supplier, and/or bolts torqued to the lower end of the range.

The only problem I have with your theory is that this is a very old issue and if it was as simple as a gasket and/or torque issue then why did Ford not have a Recall? I unfortunately think the problem is more complex and could be associated with the aerodynamics of the car/exhaust pipes, etc., causing a vacuum and to seal everything perfectly could be costly. By no means am I pin pointing the problem, just a guess.

I've said it before, the most problematic part of this problem is that carbon monoxide is a tasteless and odorless gas, so unless another exhaust constituent like sulfur dioxide (pungent type of odor), hydrogen sulfide (rotten egg type of odor), hydrocarbons (oil or gas type of odor), nitrogen oxides (sweet type of odor), etc., is giving you an indication via an odor, you would never know you have an exhaust leak into your cabin.

 

[Jon M]

The only problem I have with your theory is that this is a very old issue and if it was as simple as a gasket and/or torque issue then why did Ford not have a Recall? I unfortunately think the problem is more complex and could associated with the aerodynamics of the car/exhaust pipes, etc., causing a vacuum and to seal everything perfectly could be very costly. By no means am I pin pointing the problem, just a guess.

I've said it before, the most problematic part of this problem is that carbon monoxide is a tasteless and odorless gas, so unless another exhaust constituent like sulfur dioxide (pungent type of odor), hydrogen sulfide (rotten egg type of odor), hydrocarbons (oil or gas type of odor), nitrogen oxides (sweet type of odor), etc., is giving you an indication via an odor, you would never know you have an exhaust leak into your cabin.

It's definitely not a simple issue, or they would've fixed it by now. If it is a gasket or torque issue that only happens in limited circumstances, it would be very difficult to find, because it wouldn't be be obvious. Unless they went through vehicles and deliberately re-torqued the bolts and/or replaced the gaskets, they'd never figure it out. If they checked and found them "within spec", and the problem is with the spec, then they still wouldn't find it easily.

Whatever the issue, they obviously haven't solved it, as it's still being reported after the TSB is performed, so there's something they're missing.

It took them a year to admit to a problem, and now five years later, they still haven't figured it out.

 

[Sixonemale]

Whatever the issue, they obviously haven't solved it, as it's still being reported after the TSB is performed, so there's something they're missing.

It took them a year to admit to a problem, and now five years later, they still haven't figured it out.

Simply put, if you put a few smart engineers, in addition to lots of sensors/detectors on this problem and throw enough money at it, it should not be that difficult to solve. It's not rocket science.

 

[omar302]

Simply put, if you put a few smart engineers, in addition to lots of sensors/detectors on this problem and throw enough money at it, it should not be that difficult to solve. It's not rocket science.

+1

Maybe that is one of the reasons Ford had the recent management shake up.

 

[CommandPresence]

Not sure if anyone has seen this yet.

 

[peterk9]

Yes, that has been posted in this thread but always a good reminder. http://www.explorerforum.com/forums...ring-acceleration.323597/page-55#post-3350795

https://www.kane.co.uk/knowledge-centre/what-are-safe-levels-of-co-and-co2-in-rooms

Peter

 

[Jon M]

I have no doubt that after step 1 of the TSB, the problem is the same, or worse. I also confirmed this morning that it doesn't have to be WOT; sustained running just shy of 3000 RPM, in the 2700-2800 range, while climbing a bridge, brought it in just as much. All of this was without recirculate on.

 

[stillmarried]

Got a new 2017 to replace the exhaust smell in my 2015. Had to put the windows down on fhe way home from the dealership to get the exhaust smell out of our new 2017 with 20 miles on it Been with Ford since my used 72' Pinto, but I am plum discouraged.

 

[peterk9]

Got a new 2017 to replace the exhaust smell in my 2015. Had to put the windows down on fhe way home from the dealership to get the exhaust smell out of our new 2017 with 20 miles on it Been with Ford since my used 72' Pinto, but I am plum discouraged.

I believe you're the first to report it with a 2017.

Peter

 

[Sixonemale]

Feds probe exhaust fumes filling Ford Explorer

U.S. auto-safety regulators are investigating the possibility that exhaust fumes are leaking into certain versions of the Ford Explorer sport-utility vehicle.

The National Highway Traffic Safety Administration launched a probe into the matter in July after receiving 154 complaints of "occupants smelling exhaust odors in the occupant compartment, some of which expressed concerns about exposure to carbon monoxide," according to a government document.

The NHTSA investigation covers 2011 to 2015 Explorers.

But CBS News reported Monday that the number of complaints has mushroomed to more than 450, including 2016 and 2017 models. The news organization also reported that Ford recently agreed to settle a class-action lawsuit involving the alleged defect in a case filed in Florida.

I believe you're the first to report it with a 2017.

Peter

Perhaps he was the first one to report a 2017 with this problem in forum, but as shown above this problem or complaint has occurred with other 2017 Explorers.

 

[tlfksu]

I believe you're the first to report it with a 2017.

Peter

I've been lurking a long time on this forum and watching the progress of this issue. Finally joined and figured I would chime in. We have this issue in a 2017 Explorer Sport.