Horrendous exhaust odor

[mr cribb]

As the title states, I have this horrendous exhaust odor that seems to be coming from under the hood.

I suspect the intake gasket has failed, but I want other opinions.

The truck is a 92, 12/91 build date, 223k miles, to my knowledge original everything, with the exception of what I have replaced, since ownership in 12/10. That is normal wear out items; plugs/ wires, oil/filter changes, serp belt, rad/ hoses, 3 t-stats, heater core.

(Everything else I've done is non engine related)

The smell is pretty much debilitating, (I honestly don't know how folks kill themselves by carbon monoxide poisoning), I can't stand to drive the truck for very long and yet I have to while delivering pizzas.

If I switch the heat to the vent setting I get light headed quickly (when engine is warm). I drive with the windows down or half down to combat the stench.

I know it is NOT the cat convertor (it is cleaned out, and yes it smelled this bad before cleaning). (Done 2 weeks ago)

When I ran seafoam thru the intake it helped the smell for a few days, but otherwise did what it was supposed to do. (This was done 2 weeks ago)

Before someone says it: I DID SEARCH THE FORUMS AND GOOGLE BEFORE POSTING.

Thanks for any and all help,
J. Cribb

 

[Dano!]

Does it smell like death? Like a dead animal? Or just nasty.

I would eliminate the cooling system by draining some of the Rad fluid after the engine warms up, see what it smells like.

If its just a strong exhaust smell which i think is what your describing, you can check your charcoal box emission scrubber *thing. If its cracked or the rubber tubing is torn, it can give you some of that smell. ( mixed with gasoline fumes)
Did the sea foam treatment expose any leaks?

 

[mr cribb]

Does it smell like death? Like a dead animal? Or just nasty.

I would eliminate the cooling system by draining some of the Rad fluid after the engine warms up, see what it smells like.

If its just a strong exhaust smell which i think is what your describing, you can check your charcoal box emission scrubber *thing. If its cracked or the rubber tubing is torn, it can give you some of that smell. ( mixed with gasoline fumes)
Did the sea foam treatment expose any leaks?

No it is a very bad exhaust odor that permeates through the inside when engine is warm, it stinks bad when engine is cold (but only on outside).

So it pretty much smells rich or fumy all the time. Wife says it kinda smells like gas and has done so for a year or so.

I don't think the seafoam exposed any leaks, the truck doesn't lose any coolant which some intake gasket symptoms have noted such events (that I read on here).

 

[Dano!]

Are your headers still stock? ( pretty much everything from the cat back is new) i want to say it sounds like a header gasket ( that is where my exhaust smell came from) the leak may be small like mine was, even with the sea foam the only way to see it was with a flash light looking right at it. I would recommend letting a buddy do the seafoaming, and have you inspect the headers and the flanges ( more likely its going to be on the passenger side)
By no means am i suggesting you did not do a thorough job, my experience when i was trying to find the same thing was that a small leak or several small leaks can make this happen. My leaks were on the passenger header, passenger flange, and where the headers connected to the cat.

I hope this helps because it was embarrassing when i gave people rides and had to explain what they were smelling.

 

[Roadrunner777]

Is the smell immediate or after the engine has run a few minutes? I don't know if your year has EGR but if so, that's an exhaust leak point. The gas fume canister, again, if you year has one, is also a possibility. Say you open the hood and rev the engine, do you hear an exhaust leak?

Driving a vehicle with a notable exhaust leak is obviously hazardous. That you are using this vehicle for deliveries means you are in it for at least a few hours a day. I want you to do something, like, today. Find or buy a cheap home CO detector and put it in your truck. If it goes off while you driving around, you need to do something quick. I'm sorry the truck is your source of income, and this could be a complication. But, we would miss you if something bad were to happen. Today, ok, take it off the wall at home, do whatever you have to do. CO is odorless and deadly.

 

[wood1]

Sounds like an exhaust leak Jeremy. Have you inspected all your exhaust? How did you clean the converter? I have never heard of that. I thought that when they start to plug up they overheat and melt inside, blocking exhaust flow to the tail pipe. The resulting back pressure can cause a leak at the manifolds etc.

Don't drive it if you have a leak. You are going to make yourself and your family sick. Carbon monoxide displaces oxygen in the blood stream. Very dangerous.

 

[mr cribb]

How did you clean the converter?

Lol Chris, I ummm took it down and ummm "cleaned it out" and put it back up

No leaks from manifolds back.

 

[MillerTime941]

I had a similar problem when i bought my explorer a couple months ago, I found the previous owner had bypassed the canister purge valve. The result was a terrible exhaust smell under the hood, I'm not sure if it pulled through the vents as I ride with the windows open (ac is broke and no need for the heat yet here in florida).

I just installed a new purge valve solenoid in it last week and my pcm took a crap on me two days later so i wont know truely until monday when the mailman brings me my new computer how well it truely works. But in the short time it was running i did notice a big difference in the exhaust smell.

Im just learning my way around this motor and yours may not have the same setup under the hood, but it maybe somewhere to look.

 

[mr cribb]

Are your headers still stock? ( pretty much everything from the cat back is new) i want to say it sounds like a header gasket ( that is where my exhaust smell came from) the leak may be small like mine was, even with the sea foam the only way to see it was with a flash light looking right at it. I would recommend letting a buddy do the seafoaming, and have you inspect the headers and the flanges ( more likely its going to be on the passenger side)
By no means am i suggesting you did not do a thorough job, my experience when i was trying to find the same thing was that a small leak or several small leaks can make this happen. My leaks were on the passenger header, passenger flange, and where the headers connected to the cat.

I hope this helps because it was embarrassing when i gave people rides and had to explain what they were smelling.

Yes the stock manifolds are still on, I haven't noticed any leaks. I have heard vehicles with busted manifold/ donut gaskets, and mine doesn't sound like that.

When I took the cat down to "clean it" I installed a new flange gasket. For $5 it was cheap enough to just replace it.

 

[mr cribb]

Is the smell immediate or after the engine has run a few minutes? I don't know if your year has EGR but if so, that's an exhaust leak point. The gas fume canister, again, if you year has one, is also a possibility. Say you open the hood and rev the engine, do you hear an exhaust leak?

It is mostly after the engine is warm and been running for several hours.

Mine is not equipped with an egr valve.

With hood open engine running fiddling with the throttle, no exhaust leaks heard.

 

[mr cribb]

If its just a strong exhaust smell which i think is what your describing, you can check your charcoal box emission scrubber *thing. If its cracked or the rubber tubing is torn, it can give you some of that smell. ( mixed with gasoline fumes)

The gas fume canister, again, if you year has one, is also a possibility.

I had a similar problem when i bought my explorer a couple months ago, I found the previous owner had bypassed the canister purge valve. The result was a terrible exhaust smell under the hood, I'm not sure if it pulled through the vents as I ride with the windows open (ac is broke and no need for the heat yet here in florida).

I just installed a new purge valve solenoid in it last week and my pcm took a crap on me two days later so i wont know truely until monday when the mailman brings me my new computer how well it truely works. But in the short time it was running i did notice a big difference in the exhaust smell.

Im just learning my way around this motor and yours may not have the same setup under the hood, but it maybe somewhere to look.

Well this is 3 votes to check the charcoal canister, I will look into fixing this.

I really need to fix it quickly due to the fact of I will be moving at the end of December and transporting my 3 cats, I would hate for one of them to keel over due to a broken part.

 

[Dano!]

Usually one of the two black caps are broken or a crack in the hoses. My manufacturer maintenance manual says they are rated for ten years of use. So most of ours are way out of their perceived functional limit.

X2 on the Kitty's i would feel terrible if one of my cats became sick while in transport.

 

[mr cribb]

Usually one of the two black caps are broken or a crack in the hoses. My manufacturer maintenance manual says they are rated for ten years of use. So most of ours are way out of their perceived functional limit.

X2 on the Kitty's i would feel terrible if one of my cats became sick while in transport.

The only part listed at the parts houses is the solenoid, and that is for $40-$50.

Not to sound ignorant but we ARE referring to the black round canister by driver side headlight, correct? I am not looking at it at this point (too stinking cold outside).

So look for split hoses around the vicinity of it?

 

[Dano!]

This is what my book says concerning how the carbon canister is supposed to work.

FUEL EVAPORATIVE EMISSION SYSTEM

the evaporated emission system limits the amount of fuel vapor a vehicle releases to the atmosphere in accordance with current federal and state requirements for fuel evaporation. The evaporative emissions system functions by capturing a very high percentage of fuel vapors vented from the fuel tank. These vapers are directed to the carbon canister where they are stored when the engine is not running. Wind conditions are aceptable, ( engine running, manifold vacuum and temperature within specification), both stored and recently generated vapors are purged into the engine air intake stream for consumption by the engine. Thus, The carbon canister is purged of stored vapers and prepared for future fuels vaper storage.

Fuel vapors are vented through a hose or tube from the top of the fuel tank to the carbon canister. Hey hose or tube directs vapors from the carbon canister to the engine permitting carbon canister purgeing, and vapor consumption by the engine.

The evaporative emissions system, regardless of application, establishes a path between the fuel vapor slice (fuel tank) and a fuel vapor storage area (carbon canister). Additionaly, a path is established between the carbon canister in the engine air intake stream to provide canister purgeing and vapor consumption by the engine.

It says the tube between the carbon canister and the intake is connected to the throttle body vacuum fitting.

Carbon canister purging occurs as fresh air is introduced into the system, passed through the carbon canister and into the engine air intake stream. The fresh air is directed to the carbon canister where it passes over the activated charcoal bed and releases stored fuels vapors. The fresh air/ fuel vapor mixture is vented from the carbon canister to the throttle body vacuum fitting where it is introduced into the engine air intake stream.

The book also mentions you may have excessive fuel pressure, injector might be stuck open or an o ring is leaking.

Also make sure there is no liquid in the canister, that means the canister is bad and might mean the vent system on your fuel tank is malfunctioning.

But after reading all this in the book, it doesn't seem like this is your issue. And i would hate to see you spend money on something that might not work. This would give you a gas smell more than an exhaust smell.

I am doing this on my phone and can't see if you have replaced your O2 sensor, if you haven't then i would check that out and make sure it in there correctly and has not cracked.
When i put my new catalytic converter on it came with a gasket that once heated turned into a hard fragile plate. It disintegrated and cause a leak, and i had to but a better gasket on.

 

[Dano!]

Im going to keep reading the book, i can't seek to find any troubleshooting guidelines concerning exhaust fumes from inside the engine bay other than a bad seal or a cracked manifold. All shat should have been apparent when you sea foamed the engine.

The first thing i would do is sea foam the **** out of that thing and look over that exhaust system like it stole your wife's wedding ring.

 

[wood1]

Ha ha ha, I've cleaned a couple converters in my time too Jeremy!

 

[mr cribb]

Hey hose or tube directs vapors from the carbon canister to the engine permitting carbon canister purgeing, and vapor consumption by the engine.

It says the tube between the carbon canister and the intake is connected to the throttle body vacuum fitting.

Carbon canister purging occurs as fresh air is introduced into the system, passed through the carbon canister and into the engine air intake stream. The fresh air is directed to the carbon canister where it passes over the activated charcoal bed and releases stored fuels vapors. The fresh air/ fuel vapor mixture is vented from the carbon canister to the throttle body vacuum fitting where it is introduced into the engine air intake stream.

The book also mentions you may have excessive fuel pressure, injector might be stuck open or an o ring is leaking.

Also make sure there is no liquid in the canister, that means the canister is bad and might mean the vent system on your fuel tank is malfunctioning.

But after reading all this in the book, it doesn't seem like this is your issue. And i would hate to see you spend money on something that might not work. This would give you a gas smell more than an exhaust smell.

I am doing this on my phone and can't see if you have replaced your O2 sensor, if you haven't then i would check that out and make sure it in there correctly and has not cracked.
When i put my new catalytic converter on it came with a gasket that once heated turned into a hard fragile plate. It disintegrated and cause a leak, and i had to but a better gasket on.

Wow good feedback, I greatly appreciate it. I will look at the hose(s) from the canister to the throttle body.

I haven't replaced the O2 sensor for 2 reasons; (1)no CEL on for it, (2) gas mileage hasn't taken a dump as previous cars I had with this problem have done.

If I did have a leaking injector / injector o ring wouldn't the gas mileage suffer as well?

The thing I have noticed is when engine is hot I smell the smell more as to explain a cracked rubber hose.

 

[mr cribb]

I seemed to have resolved my issue....

The tiny little culprit:

Located here: (far away)

(up close)

I had a piece of vacuum hose available, replaced it and drove around with the heat on for about 30 minutes, purposely went to a drive thru to pick up food and smell is all about 99% gone. It still stinks, but not near as atrocious as before.

Before replacing the piece of hose going to a drive thru sitting at idle was a no go.

I am clearly okay fixing the problem for free for now, it beats the heck out of spending money I don't have right now.

Thanks to all that helped, and I hope if someone else has a similar problem they can use this as a guide.

If any issues return I will be sure to report my findings back in this thread.

 

[wood1]

Free is awesome. Glad you got it figured out dude!

 

[Dano!]

Good job man,
I am glad it was something easy And right there in the open.