Bad or Burnt Exhaust smell in cabin during hard acceleration.

[Albert (CO Toxicologist)]

Thanks for this informative post. I am curious of how many Ford Explorers that you have tested, and of that number, how many did you find CO levels inside of the cabin? Are there any specific brands of CO detectors that you can recommend to take these measurements in our own cars, without breaking the bank? Thanks again...

So far I have checked only 3, but CO was over 20ppm in all of them (all unmodified),
vs CO in ambient air less than 1ppm.

As for professional portable CO detectors that can display accurately from 1ppm, anything you can find via Google in the $100 to $300 range should be sufficiently accurate, but most of these devices can only record a peak CO level, not continuously. I have just ordered several new models for testing that retail for under $75 and will let the forum know if any are sufficiently accurate for this application.

 

[Albert (CO Toxicologist)]

Albert, In the case above what happens to the CO concentration when the internal ventilation is on recirculate vs introducing outside ambient fresh air into the cabin, therefore no dilution?

CO level rises when AC is ON and recirculate is ON (no dilution) and falls when recirculate is OFF (max dilution). The problem is not caused by exhaust coming in the fresh air vents, but rather by exhaust coming in through insufficiently sealed seams and holes all around the back hatch, under the rear floor, and under the rear quarterpanels.

 

[Sixonemale]

So far I have checked only 3, but CO was over 20ppm in all of them (all unmodified),
vs CO in ambient air less than 1ppm.

My point exactly, if you are introducing outside ambient CO at 1 PPM with internal ventilation not on recirculate, the CO PPM from exhaust would get diluted. If the internal ventilation is on recirculate then the reading would be more accurate and represent a worst case situation that could be occur on a very hot day when someone is accelerating but also trying to cool down the cabin as quickly as possible. When you checked the CO concentration was the internal ventilation is on recirculate or not, or was your measurement the peak reading?

 

[Albert (CO Toxicologist)]

When you checked the CO concentration was the internal ventilation is on recirculate or not, or was your measurement the peak reading?

I checked both with recirculate on and off. The measurements I reported above were the peaks seen during continuous monitoring with recirculate on. Within a few minutes of turning recirculate off, the CO level falls to <3ppm (but you have to keep fan on high)

 

[KayGee]

CO level rises when AC is ON and recirculate is ON (no dilution) and falls when recirculate is OFF (max dilution). The problem is not caused by exhaust coming in the fresh air vents, but rather by exhaust coming in through insufficiently sealed seams and holes all around the back hatch, under the rear floor, and under the rear quarterpanels.

Trying to understand this better, but it seems to me that if there are that many insufficiently sealed seams and other holes in the Explorer, then that would mean there are likely general build quality issues and lack of QC, which should also manifest in other ways like excess cabin noise or ? One would also think this would impact other similarly designed/constructed vehicles as well, especially Ford vehicles, as there are probably some shared assembly practices. Have you tested other Ford vehicles of similar design/construction (Escape, Edge, Flex) to see how their CO levels compare to the Explorer under the same conditions?

I checked both with recirculate on and off. The measurements I reported above were the peaks seen during continuous monitoring with recirculate on. Within a few minutes of turning recirculate off, the CO level falls to <3ppm (but you have to keep fan on high)

Was this under the test conditions you mentioned (WOT from a 45 roll) or under more 'normal' driving conditions?

 

[Albert (CO Toxicologist)]

Trying to understand this better, but it seems to me that if there are that many insufficiently sealed seams and other holes in the Explorer, then that would mean there are likely general build quality issues and lack of QC, which should also manifest in other ways like excess cabin noise or ? One would also think this would impact other similarly designed/constructed vehicles as well, especially Ford vehicles, as there are probably some shared assembly practices. Have you tested other Ford vehicles of similar design/construction (Escape, Edge, Flex) to see how their CO levels compare to the Explorer under the same conditions?

Was this under the test conditions you mentioned (WOT from a 45 roll) or under more 'normal' driving conditions?

Obviously a QC issue, given that most of the resealing recommended in tsb17-0044 is supposedly recognizable by visual inspection.. (And so should have been caught during production).

I have measured 0ppm under similar conditions in an Expedition and an Escape but that does not mean they are all safe. All hatchbacks leak eventually when their rear door seal tears , comes loose, or rots.

Best to compare odor complaints posted by owners of other vehicles.

 

[Sixonemale]

I checked both with recirculate on and off. The measurements I reported above were the peaks seen during continuous monitoring with recirculate on. Within a few minutes of turning recirculate off, the CO level falls to <3ppm (but you have to keep fan on high)

Exactly how I thought you would reply, thanks. It's fairly obvious that the potential danger of high CO concentrations occurs when the internal ventilation is on recirculate and if I recall correctly, probably not all, but several of the police department complaints that were listed in this thread occurred during spring and summer months which makes sense, a hot day with the AC on Max and then driving at WOT or maybe even simply driving over 40 MPH. For those others that have complained about smelling exhaust, but not feeling any effects of CO, perhaps the concentrations were not all that high and/or were diluted by not having the ventilation on recirculate. As to whether the exhaust is coming from small cracks in the manifold in addition to exhaust from the exhaust pipes, who knows unless each Explorer is fully inspected or Ford can say cracks in the manifold do not exist in civilian owned Explorers.

 

[Sgt1411]

http://www.leftlanenews.com/ford-downplays-risk-of-explorer-exhaust-fumes-complaints.html

 

[Sixonemale]

http://www.leftlanenews.com/ford-downplays-risk-of-explorer-exhaust-fumes-complaints.html

I sure am glad the National Highway Traffic Safety Administration (NHTSA) is involved in the exhaust/carbon monoxide issue and is pushing forward with an engineering analysis. Ford is using statistics on Explorers sold vs number of complaints rather than properly addressing the issue by doing an internal engineering analysis to really figure out the root cause. Unless owners are driving at WOT with ventilation on recirculate and/or when driving above 40 MPH with ventilation also on recirculate, the problem may never be noticed, but it does not mean the potential problem does not exist.

In summary, from the link above:

The agency has identified nearly 800 complaints related to exhaust odor claims, including three crashes and 41 injuries allegedly related to the issue. Ford has also uncovered 2,400 reports including owner complaints, warranty claims, dealer field reports and legal claims.

"The reported injuries range from unspecified to loss of consciousness, with the majority being nausea, headaches, or dizziness, all of which can be symptomatic of carbon monoxide exposure,"

 

[thefranchise713]

A small update on this from me.

I've been having better experiences lately. I got the new HVAC calibration and 17-0044 done, and it seems to have helped--between the calibration and new air extractors (new design looked different than the old) I didn't have issues yesterday, and I climbed enough grades to feel like I'd have a good data point. 650 mile roadtrip back and forth across New York State yesterday for 26 MPG at that.

I had about 80 degree temps, drove 2 miles up a steep grade, and separately got in at least one hard acceleration... I feel like it would have gassed me out if it were going to. HVAC was full auto.

So, I'm still having a litany of other issues with this car, but at least that one seems to have evaporated for the moment.

 

[Albert (CO Toxicologist)]

A small update on this from me.

I've been having better experiences lately. I got the new HVAC calibration and 17-0044 done, and it seems to have helped--between the calibration and new air extractors (new design looked different than the old) I didn't have issues yesterday, and I climbed enough grades to feel like I'd have a good data point. 650 mile roadtrip back and forth across New York State yesterday for 26 MPG at that...

That sure was a long test drive! Good to know Ford's TSB 17-0044 can stop exhaust odor in some cases. Can you tell us if your repair included replacing the exhaust manifold, the exhaust pipe tips, or the rear door seal?

 

[Sgt1411]

What are air extractors?

 

[thefranchise713]

That sure was a long test drive! Good to know Ford's TSB 17-0044 can stop exhaust odor in some cases. Can you tell us if your repair included replacing the exhaust manifold, the exhaust pipe tips, or the rear door seal?

Negative, negative, and negative. In addition, they didn't find any seams that needed sealing, either.

What are air extractors?

They're behind the bumper fascia on the left and right sides of the vehicle, they vent the air pressure when the doors are shut with the windows closed.

 

[thefranchise713]

Strike everything I said. I had the issue again today... damn.

 

[Dfred]

Strike everything I said. I had the issue again today... damn.

Damn for sure...... I had the recall done a few weeks ago.... so far it's holding knock on wood.......

 

[Albert (CO Toxicologist)]

Strike everything I said. I had the issue again today... damn.

Sorry to hear the first fix didn't work. Can you tell us how fast you were going when you noticed the odor again, and if AC was on recirculate or off?

Since Ford didn't replace your exhaust manifold, rear door seal or exhaust tips, I suggest you try asking for these repairs next.

 

[thefranchise713]

Exhaust manifold passed inspection. Exhaust tip TSB didn't apply to the 2.3L engines.

Conditions were as follows:
Ambient: 82F
Throttle: half-3/4ths
HVAC: full automatic, including AC; recirc button NOT engaged (but HVAC strategy may have had it engaged to some degree)

Tonight I came off the same tollbooth where it happened earlier today... couldn't reproduce, same conditions except night and now 71 instead of 82.

 

[Albert (CO Toxicologist)]

Exhaust manifold passed inspection. Exhaust tip TSB didn't apply to the 2.3L engines.

Conditions were as follows:
Ambient: 82F
Throttle: half-3/4ths
HVAC: full automatic, including AC; recirc button NOT engaged (but HVAC strategy may have had it engaged to some degree)

Tonight I came off the same tollbooth where it happened earlier today... couldn't reproduce, same conditions except night and now 71 instead of 82.

So that just leaves the rear door seal to replace. That alone could be the problem, or more likely, the dealer didn't do all the recommended sealing of seams and holes. To see if you can reproduce the odor, I suggest trying acceleration with HVAC recirculate ON instead of in automatic.

 

[Odrapnew]

Doesn't the tail gate have a few drain windows on the bottom? If so, are they inside or outside of the rear tailgate seal? If outside, could that be a possible entrance point? I would think they'd be on the outside since I think they would be designed to drain any water out from inside the tailgate.

 

[Jon M]

Doesn't the tail gate have a few drain windows on the bottom? If so, are they inside or outside of the rear tailgate seal? If outside, could that be a possible entrance point? I would think they'd be on the outside since I think they would be designed to drain any water out from inside the tailgate.

Replacement drains are part of the first step of the TSB.