Exhaust fumes coming into the cab

[blackbeauty]

I've got a single side 3'' exhaust exiting out the passenger's side. I am getting fumes coming into the cab with the top and doors off. Does anyone have any recommendations that might help or hopefully stop the fumes from coming in?

I bought a tip thinking getting it out past the tire might help, but there is no change.

 

[broncnaz]

No real answer as with no top air will flow back into the cab. Of course if the engine is tuned properly you wont smell the exhaust but that only means you could still get gassed out by carbon monoxide which you wont smell. Probably not a huge deal being that the your not enclosed as you will get fresh air.

Another issue I think might be the 3in exhaust as the exhuast gases are not coming out with as much force as say they would with a 2.5in or smaller exhaust. A smaller exhuast may allow the exiting gases to shoot farther away from the vehicle so you get less smell in the cab. Of course this is only a guess on my part but it kinda makes sense.

 

[DirtDonk]

Agree with broncnaz. Although that looks more like a 2.5" to me. But if it's 3", it would probably act as he says.
You've pretty much got it aimed correctly from most experiences we've had. Any other angles or locations of the tip and it pretty much just dumps exhaust right over and into the passenger compartment.
The only thing saving you from a worse fate right now is the fact that the top and doors are off!

You could block off the stake pocket holes and any other holes that lead into the cab. Even though it wouldn't get rid of the fumes completely, as they're tumbling and turbulating all over the place back there, removing some of the entry points into the cabin would certainly help.
Did for me.

To test that theory, you can temporarily block off all holes, including the stake pocket tops, unused rear seat and seat-belt holes, old antenna holes, shifter gaps in the tunnel, etc. Any entrance should be covered. Should help a little at least.
Can't hurt anyway.
Inspect the fuel lines (even if they're all brand new) to make sure you're not getting some raw fuel smell mixed in there, and make sure the engine is totally tuned up like he said. Also makes a difference.

Good luck. Fumes suck!

Paul

 

[rustbucket]

Are you sure you don't have an exhaust leak somewhere?

 

[Broncobowsher]

Generally that location is the best possible choice.
Generally the issue is worst with the doors and roof on.
The fact you are getting that with your current combonation is very wierd. At this point I would be giving upa and installing a high flow catalitic convertor to clean up the tailpipe.

 

[Bulletman]

He is experiencing this with the top OFF.......

 

[blackbeauty]

For some reason the picture makes the pipe look small. It's 3". The tire is a 35'' on 17s.
I sealed off all of the holes in the floor before I painted it, but I have a few unused open holes in the firewall. I will plug those and see if that helps. My thinking is that it might "pressurize" the cab from the front and keep the fumes from being sucked in from the back. Is that backwards thinking? Dyslexia get the best of me sometimes.
Everything is new on it since I did the efi swap and I even put a cat on thinking it would help.
I have never liked how low my exhaust guy put the tailpipe and am planning on having it raised. I have notice that Nick's Trix mounts his exhausts up high close to the body and it looks great. The guy that did mine said he left it low so it would not trap moisture and rot out.??
A little history, The exhaust guy only had a flowmaster when I had it done the first time and I HATED the noise and could not stand the resonation coming thru the body, so I ordered a turbo muffler and installed and just cut it and dumped down right in front of axle just to get it back on the road (the TM had a different side outlet). The fumes weren't that bad on the road, but would get pretty strong while idling. So I had the new tailpipe reinstalled to hopefully get rid of all the fumes, with only mild improvement. Now I'm here getting everyone expert recommendations before have it changed again. Thanks for the input!!

 

[broncnaz]

With EFI and a Cat you shouldnt be able to smell much of anything. Sounds like its way out of tune.

 

[jarhed1984]

Took the bronc to the muffler shop today. Had the pipes changed from straight back to out behind the wheels. MAJOR, major difference. The wife has decreed it exhaust free. Thanks to everyone for the advice.

 

[patterdale]

Try a 90 degree turn to the rear right in the middle of the tire. With no top it is going to be hard to keep fumes from coming in. We have a full top and have no fume issues either gas or exhaust.

 

[half cab]

Have you checked to make sure your peek-a-boo plates are still in place behind the tail light housing?

If they are missing and pipe exits behind wheel like that it will tend to come up in the cab...noise too and with the top on it's real bad!!

 

[blackbeauty]

Try a 90 degree turn to the rear right in the middle of the tire. With no top it is going to be hard to keep fumes from coming in. We have a full top and have no fume issues either gas or exhaust.

Do you think a 90º bend would be better the 60-70º it is now?

Have you checked to make sure your peek-a-boo plates are still in place behind the tail light housing?

If they are missing and pipe exits behind wheel like that it will tend to come up in the cab...noise too and with the top on it's real bad!!

Good call. I siliconed these in before I painted the inside not even thinking about fumes. I was worried about water/mud migrating up there.


I did replace the tail gate seal and it helped a little.

 

[patterdale]

Do you think a 90º bend would be better the 60-70º it is now?


Elmer's goes to about the middle of the tire and turns straight back to the rear. He is bone stock original otherwise. The muffler and tailpipe were replaced by the PO before we bought him. I can only assume the PO did it like it was done originally. There is absolutely no exhaust stink in the cab. Maybe one other thing that is affecting this for some is the original pipe is fairly small in diameter which increases velocity of the gasses coming out and forces them out of the low pressure area. A bigger pipe would allow them to slow down and be caught up. A bigger pipe might improve flow through the engine and boost HP but this could be the trade off.

 

[Oakland Bronco]

Took the bronc to the muffler shop today. Had the pipes changed from straight back to out behind the wheels. MAJOR, major difference. The wife has decreed it exhaust free. Thanks to everyone for the advice.

Hey...you didn't update the other thread! I've been watching to see whether the re-route helped but hadn't seen any updates. Glad the re-route helped and the Bronc is wife-approved.

 

[patterdale]

Glad it worked out for you and especially your wife. We need all the "enablers" (wives)we can get for this addiction.