When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I am experiencing an issue which is confounding me and my local Porsche-centric indy. I am frustrated, really hoping the collective wisdom and problem solving of this group can solve the mystery.
The problem: Extremely strong exhaust smell in the cabin, even with the top down. It is so strong I cannot drive the car. After driving and parking the car the smell is very strong near the air intake vents. There is no smell at the exhaust tips. It is possible the smell is not exhaust but something else burning.
Background: I've had the car for 4.5 years. The issue started after the catalytic converters were replaced several months ago. I returned the car to the indy and he thoroughly inspected the car after i encountered the exhaust in the cabin. He found nothing from replacing the cats that would have caused this. Another variable which may or may not be a contributing factor, around the same time the cats were replaced the oil was changed and the oil level was to the max. I was concerned that this may have been the cause. My indy checked the AOS and said it was fine.
some how you will have to figure out whats the stink.....usually a good mechanic can tell the difference from tail pipe fumes to coolant to motor oil to raw gas . a small anti-freeze leak can be a big stink .are you getting the smell near the intakes while the car is running or off ?
I have not checked while it was running (will do later today). But definitely after. I ran the car only a mile or so on Saturday afternoon (I couldn't take the fumes any longer than that) and as of Monday morning the intakes still smell like the cabin did during operation.
About the only way I know of exhaust to get in the cabin would be if one of the air vents at the rear of the car -- under the bumper cover and kind of off to each side -- is open and low pressure in the cabin --which normally would have these vents closed -- is pulling exhaust (or engine compartment) fumes into the cabin through a fvent.
Those vents are some kind of soft rubber -- at least the ones on my Boxster -- that simply work via pressure or the lack of it and gravity so there is not much to go wrong. However, if mice have been at the car -- or the car was subjected to lousy accident repair maybe -- one or both of these could be damaged.
If you put the top up and the windows up and turn on the cabin vent fan and bring in outside air this should have the cabin under positive pressure and you should not then smell anything. The positive pressure would have the air flowing into the cabin from the air intake just ahead of the windshield and out through the vents are the rear of the car.
Be aware the cabin air filter can develop an odor -- to my nose a sour/moldly odor -- which can have the cabin smelly or if the body water drains that are also just ahead of the windshielf are full of trash this trash if damp and it will be can also stink and the incoming outside air will pick this up and carry it into the cabin.
What happens much more often is something blows up against the hot exhaust and if this is some kind of plastic or plastic paper it can stick and char as the exhaust gets hot. Char and stink. I have found small pieces of charred cigarette wrapper on top of my Boxster's engine under the intake manifold.
If you can get the car in the air you should be able to with a flashlight and a mirror on a stick give the exhaust system a thorough check. Look too for anything loose -- exhaust or engine wiring harness, vacuum hose, anything -- that could allow the exhaust and whatever to come into contact.
IIRC the O2 sensors each have some kind of gromet that is used to hold the O2 sensor wiring lead secure so it can't move about. If during the exhaust work if one of these was overlooked...
So, I have some interesting updates. The fumes were stronger on the driver's side than passenger in the cabin. But, the fumes were nonexistent on the driver's side intake and tailpipes. Extremely strong at the passenger's side intake. While on the way back to the indy it threw a CEL with a ton of codes. Indy opened the top of the engine to discover that there had been a fire. In retrospect, i can tell you when the fire occurred. It was a week or two before i originally posted. The fumes were present for months and several hours of drive time prior to the fire. I do not think the fire was the cause of the fumes. If anything, I think that the source of the fumes may point to what caused the fire.
Has anyone heard of a Boxster catching on fire in this manner? Any thoughts on the cause?
That's an interesting location. No oil drips of gasoline leaks likely there. My guess would be a mouse nest fire started by an electrical short caused by the mouse gnawing on it.
I'm with Anker. Rodent litter maybe. Less likely is something initially contacted the hot exhaust then got dislodged and ended up there. I've found small piece of charred plastic wrap -- the kind that cigarette packs are wrapped in -- on top of my Boxster's engine.
There have been reports of someone throwing a lit cigarette out and the lit butt getting pulled into the driver's side air intake and catching the air filter (paper) on fire.
And long ago shortly after I bought my Boxster I spotted a passenger in a car next to my Boxster -- this while stopped at a light -- throwing a cigarette butt into the engine compartment vent fan air intake. The fan was not running -- it was winter.
There's no evidence of any foreign objects or critters. Car is garaged 100% of the time and we've never had any rodent sightings or other evidence of their existence. I realize this next statement is relatively meaningless, but the whole engine was taken apart in the fall of '15.
I've heard from a reliable source that these electrical fires happen. In the 996 they just seem to fry the starter and end there but in the Boxster they ignite.
In the big picture I'm grateful I didn't lose my house or worse (my wife was home alone sleeping in the house when the fire occurred with the car parked in the garage).
But I'm concerned about the root cause. Two concerns. I'm concerned that the fumes will still be there after we fix this fire damage. I'm concerned about this happening again.
There's no evidence of any foreign objects or critters. Car is garaged 100% of the time and we've never had any rodent sightings or other evidence of their existence. I realize this next statement is relatively meaningless, but the whole engine was taken apart in the fall of '15.
I've heard from a reliable source that these electrical fires happen. In the 996 they just seem to fry the starter and end there but in the Boxster they ignite.
In the big picture I'm grateful I didn't lose my house or worse (my wife was home alone sleeping in the house when the fire occurred with the car parked in the garage).
But I'm concerned about the root cause. Two concerns. I'm concerned that the fumes will still be there after we fix this fire damage. I'm concerned about this happening again.
Given the starter power wire running in the immediate proximity of the charring, and the history of the engine being taken apart, all it would take would be some improper routing of a power wire near the block and the vibrations from the engine eventually wearing the protective sheathing. This grounding out can cause some arcing and we all know the intake cross over pipes are coked with residual oil from the AOS. One of many possibilities of course.
There's no evidence of any foreign objects or critters. Car is garaged 100% of the time and we've never had any rodent sightings or other evidence of their existence. I realize this next statement is relatively meaningless, but the whole engine was taken apart in the fall of '15.
I've heard from a reliable source that these electrical fires happen. In the 996 they just seem to fry the starter and end there but in the Boxster they ignite.
In the big picture I'm grateful I didn't lose my house or worse (my wife was home alone sleeping in the house when the fire occurred with the car parked in the garage).
But I'm concerned about the root cause. Two concerns. I'm concerned that the fumes will still be there after we fix this fire damage. I'm concerned about this happening again.
Boxster electrical fires are very very rare. If they are happening they are not being reported here and other forums I frequent. Every other problem is reported to be sure.
I'm with GldMstr315: The cause is likely some wiring that was not secured properly and the insulation wore thorough and the fire was the result.
If you get the damage addressed and at the same time ensure all the engine compartment wiring is properly routed and secured the car will be safe.
'course, it is your car and your dear wife and if you are not comfortable with the car then time to get rid of it. You shouldn't have to live in fear of a car even if the fear is, and this is not the best word but until I think of a better one it will have to do, irrational.
03-27-2017, 11:25 AM
Exhaust in the cabin
