Exhaust fumes in the cabin (1 Viewer)

[Nader]

Did an exhaustive search , and still puzzled. I've been trying to isolate the source of exhaust fumes that are wafting into the cabin while I drive. Sitting at idle, it seems okay. I have an auxiliary gas tank, so the exhaust exits out the side behind the driver's rear wheel. I extended it several more inches (temporarily), but still get the issue while driving. The body is crusty with lots of holes in the rear tub, but hard to believe it's still being sucked in with the pipe extended. It's not a raw gas smell, it's exhaust fumes like it's running a little rich. And its a lot. Dangerously bad, I'd get a headache if I drove it around more than a few minutes.

I checked the length of the exhaust system and haven't found any obvious cracks, leaks, or pinched pipe. I haven't ruled out an internal blockage from a mouse or wasp nest. What made me think of that is the fact that the exhaust pressure out the tailpipe at idle seems really low, then again this is the lowest compression engine I've ever had. Otherwise, the truck runs well, and doesn't seem restricted when I floor it. Choke isn't attached, and I have to pump the gas pedal multiple times to get it to start when cold. Hot starts are instantaneous. I dunno. Any other thoughts?

 

[rkymtnflyfisher]

Desmogged?

 

[tatat]

i had the same problem on my 55. The exhaust fumes wera aspirated in the cabin due to the depression in the rear of the wagon. I just glued a gasket to make the rear doors proof et voila.

 

[reddingcruiser]

Do you have the hard top on? As you drive there is a low pressure area created directly behind the cab. Relative to the outside air, the cab air pressure is lower, so, if you have holes in the cab sheet metal the fumes take the path of least resistance and end up in the cab.

 

[Nader]

Yes, de-smogged.

Yes, hard top installed.

Weatherstripping between the rear doors and tub is quite poor. Open gaps everywhere.

*Sigh* Between this and my neighbor's friendly-griping about the truck's ugliness, I think I need to just drop it off somewhere and get the bodywork done. Make it pretty and air/exhaust-tight.

 

[Racer65]

Check the grommets in the firewall.

 

[ginmtb]

Yes, de-smogged.

Yes, hard top installed.

Weatherstripping between the rear doors and tub is quite poor. Open gaps everywhere.

*Sigh* Between this and my neighbor's friendly-griping about the truck's ugliness, I think I need to just drop it off somewhere and get the bodywork done. Make it pretty and air/exhaust-tight.

Nice neighbor... maybe take him for a ride and let him sit in the back for awhile. You're getting sleepy... very sleepy...

 

[Nader]

Nice neighbor... maybe take him for a ride and let him sit in the back for awhile. You're getting sleepy... very sleepy...

Hah! Neighbor is actually a great guy. Just some friendly (but truth-born) ribbing. I think he's a little bitter that he had an original perfect condition '77 FJ40 that he bought in the mid-nineties for $6K, and then sold a few years later for the same. Now he sees my ugly heap in the driveway, a sad reminder of what he once had and lost.

Huh, sounds like an old Fleetwood Mac tune...

 

[White Stripe]

I pour a tablespoon or 2 of atf down the carb as it's running. It causes the exhaust to smoke like crazy and it's easy to look for exhaust leaks.

 

[Nader]

I like that ATF trick.

Here's what I'm working with. I taped on that flexible metal pipe temporarily. Hoping the shiny foil draws the eyes away from the rusty holes.

 

[reddingcruiser]

What does the floor look like? Same Swiss Cheese? Once you eliminate the possibility it's an exhaust leak, you need to start plugging up the holes in the tub.

 

[Nader]

I just bought the most expensive roll of duct tape I've ever seen. Gaffer's tape. In red. About $15/roll. I'm going to tape over all the holes and gaps, and if it still stinks, I'll look for leaks and tuning/mechanical issues.

 

[thebigredrocker]

Git'r-done Nader!

As racer65 mentioned, don't forget to seal up your firewall. I may have to find some cygnus white Gaffers's duct tape for my ol' girl.

 

[4Cruisers]

I just bought the most expensive roll of duct tape I've ever seen. Gaffer's tape. In red. About $15/roll. I'm going to tape over all the holes and gaps, and if it still stinks, I'll look for leaks and tuning/mechanical issues.

I just bought a roll of 2" wide blue gaffer's tape. If I'm not mistaken, I believe it's similar to or the same as the "cotton tape" mentioned in my FJ62 FSM, the tape used to seal across the bottom of the inner door opening, where the flaps in the plastic sheet service hole cover tuck in to the door interior. The nice thing about it is the tape can be pulled off after time without leaving any tape residue.

 

[SW20]

My 79 had a leak on the exhaust manifold. It was going through my firewall.