Exhaust fumes in car

[22dog22]

After spending most of last year trying to get my 69 Cuda notch with a 318 , 904 trans running, this year was finally able to get to some car shows. Just yesterday drove about 40 miles and back from a very large show [ Gasket Goons near Hellertown Pa.] driving both ways with windows down keep getting a strong exhaust order into car. Car has a 2 1/2 stainless steel exhaust, I see/hear not leaks in system. Had noticed this prior also, have exhaust tips clamps on end of pipe, moved them out to extend them hoping that would help but did not. I am not sure what else to look at, trunk is sealed [ finished off with trim panels] , all door seals are new. Could engine just be running that rich/lean [ no black smoke seen any time ] to cause this issue?

 

[Snake]

jump in your trunk have a buddy close by close the lid and see if theres any day light, my old 69 DART did just what you said.thats how i found my fummmmssss.

 

[jbc426]

I suffered from exhaust fumes in my convertible with a .245/ .250 duration cam in a stroked 408 Magnum. It was so bad that people walking by would wave their hands in front of their face to fan away the smell wafting over to them on the sidewalk. The car was even EFI'd with a factory JTEK and a tune.

I welded on a set of High-Flow Racing cats behind the header collectors and before the crossover, and the smell was gone. I could not detect any power lose or sound change after. The were about $100 each at Summit.

 

[69FBCuda]

Where do the exits stop?

 

[Murray]

Trunk seal.

 

[AJ/FormS]

that thing got a big cam in it?
What kind of air filter house?
Sometimes, the fumes come in thru the firewall or more often, the intake cowling at the base of the windshield.
To test the exhaust, you need to pressurize it. I do this with the engine idling, and by severely limiting the exhaust flow at the tailpipes, then inspecting all the joints, and especially the Header Collectors, merges, and all-flanges..
I asked about what type of air-cleaner housing, because the factory ones usually have a pipe connecting it to the breather on the VC. If the breather is just dumped to atmosphere , it has to be sent down to in the area of the oil-pan, else underhhood air-pressure can force the fumes up to the rear hood seal, and out just above the cold-air intake for the heater., from where they get rammed into your heating system and out the ductwork. These crankcase fumes smell an awful lot like exhaust, but with an added tinge of hot or burning oil.

A big cam, tuned wrong or incompletely, can deliver a horrible stink into the tailpipes that will make your eyes water. that tune needs some idle-air bypass, and the throttle blades closed up some, cuz it's pulling way too much fuel from the transfers. Excessive Idle-Timing usually aggravates it.
The biggest cams I have tuned are 250 degrees or smaller, in street cars, so my experience is limited, But I can say, that when a car leaves my shop, it don't stink any more.

Good hunting!

 

[22dog22]

For some reason can not up load photos, the tailpipes with ext. are just past the rear bumper. I will check my trunk seal, it is new , but before I bought the car I can see it was hit and repaired to left rear area at tail light . As far as tune , it does have a new Holley 650 on it, there is a mild cam, headers, I did go up one jet size with the new Carb since my plugs where running totally white. I want to have a exhaust bug welded into the exhaust to hook up an A/F ratio gauge to see how I am running in that area. Thanks for your thoughts.

 

[1MeanA]

For some reason can not up load photos, the tailpipes with ext. are just past the rear bumper. I will check my trunk seal, it is new , but before I bought the car I can see it was hit and repaired to left rear area at tail light . As far as tune , it does have a new Holley 650 on it, there is a mild cam, headers, I did go up one jet size with the new Carb since my plugs where running totally white. I want to have a exhaust bug welded into the exhaust to hook up an A/F ratio gauge to see how I am running in that area. Thanks for your thoughts.

In my opinion it is rare that an out of the box carb would cause the car to run lean. Its always been the other way around for me. Tuning with the A/F meter is a great idea. I always do that using my old Innovate LM1. You also get to see how horrible carbs are at maintaining an A/F ratio in various scenarios.

 

[67Dart273]

"A big cam" has nothing to do with it. This is caused by BODY LEAKS. Anywhere. Rust holes, missing plugs, whatever.........holes. Bad trunk lid fit/ gasket. And AJ is right about one thing--it can come through the firewall, too. You maybe have some blowby, etc Heater / heater motor seal, even connector seals, bulkhead connector etc.

 

[jbc426]

"A big cam" has nothing to do with it. This is caused by BODY LEAKS. Anywhere. Rust holes, missing plugs, whatever.........holes. Bad trunk lid fit/ gasket. And AJ is right about one thing--it can come through the firewall, too. You maybe have some blowby, etc Heater / heater motor seal, even connector seals, bulkhead connector etc.

Are you saying having a large cam with significant overlap, where both valves are open at the same time, has nothing to do with tail pipe emissions/raw fuel smell?

 

[moparker]

Adjust your trunk lid. Needs to be tighter

 

[Dave999]

trunk seal, rear window seals, base of steering column, failed clutch rod seal, poor manual stick hole seal, firewall gaskets around heater fan etc, no seal at the trunk floor for a fuel filler pipe that comes through trunk floor and up to the back panel or side of car. floor plugs? later cars had ruberised or sealed in metal floor plugs under carpet in certain areas. missing?


exhaust fumes under the tail of the car find their way in the same as burnout smoke does


fumes can be fuel or oil if its dripping from rear seal and getting on the exhaust and trans

 

[RustyRatRod]

Get a friend and throw him in the trunk with a lit cigarette and a flashlight and gently drive around. Let him take the cigarette all around the trunk seal, around the back side of the tail lights and anywhere else that might be a suspect for a leak. He will find it.

 

[ir3333]

Yah...trunk seal or cracked / missing seam sealer on wheel houses, trunk seal lip or even rear floor seam sealer under the carpet or somewhere? The stuff does dry out and crack after 50 years?

 

[67Dart273]

Are you saying having a large cam with significant overlap, where both valves are open at the same time, has nothing to do with tail pipe emissions/raw fuel smell?

NO I AM SAYING that it has NOTHING TO DO with fuel smell IN THE INTERIOR OF THE CAR

 

[jbc426]

NO I AM SAYING that it has NOTHING TO DO with fuel smell IN THE INTERIOR OF THE CAR

OH GOT IT, NOTHING. lol,

Significant cam overlap can just contribute as a source of the actual smell inside the interior. And so, as correctly mentioned above, can improper timing, carburetor adjustments, bad seals, mis-adjusted trunks & doors, holes in the body and the exhaust and also convertibles can be possible pathways to the interior.

CONSEQUENTLY, It takes both things to experience the problem, and that's SOMETHING.

 

[1MeanA]

OH GOT IT, NOTHING. lol,

Significant cam overlap can just contribute as a source of the actual smell inside the interior. And so, as correctly mentioned above, can improper timing, carburetor adjustments, bad seals, mis-adjusted trunks & doors, holes in the body and the exhaust and also convertibles can be possible pathways to the interior.

CONSEQUENTLY, It takes both things to experience the problem, and that's SOMETHING.

All exhaust smells and is toxic so any leak path into the cabin will be a problem. I think this is obvious. The engine being out of tune is a separate issue.

 

[RustyRatRod]

OH GOT IT, NOTHING. lol,

Significant cam overlap can just contribute as a source of the actual smell inside the interior. And so, as correctly mentioned above, can improper timing, carburetor adjustments, bad seals, mis-adjusted trunks & doors, holes in the body and the exhaust and also convertibles can be possible pathways to the interior.

CONSEQUENTLY, It takes both things to experience the problem, and that's SOMETHING.

I believe Del's point was, that even of the vehicle is in perfect tune and has a leak somewhere in the rear of the car, exhaust fumes WILL BE pulled into the car. A poorly tuned engine has no effect on THAT other than "more fumes". A leak is a leak is a leak was Del's point and he's right. If the leak was not there, you'd be getting nothing into the car, regardless of the car's tune.

 

[RustyRatRod]

All exhaust smells and is toxic so any leak path into the cabin will be a problem. I think this is obvious. The engine being out of tune is a separate issue.

Right! Some folks have to argue just to try to be right when they're making themselves look stupid.

 

[22dog22]

I took a look at the trunk seal, found in the left and right lower corner area the weather seal gasket was not sealing tight, I could see light coming thought that area. I have reset the gasket [ do not see any light ] and need to road test to see if that helps/takes care of the fumes getting into my car.

 

[jbc426]

Right! Some folks have to argue just to try to be right when they're making themselves look stupid.

Case in point. Leaks and reasons some exhaust has more unburned fuel than others aside, catalytic converters can dramatically reduce the smell of unburned hydrocarbons in exhaust fumes.

Bottom line even with a perfectly sealed car and exhaust system all the way out the back. Exhaust fumes can waft into your car through open windows and convertibles with the top down. They did with my car. Adding racing cats worked for me, and can work for others.

 

[67Dart273]

OH GOT IT, NOTHING. lol,

Significant cam overlap can just contribute as a source of the actual smell inside the interior. And so, as correctly mentioned above, can improper timing, carburetor adjustments, bad seals, mis-adjusted trunks & doors, holes in the body and the exhaust and also convertibles can be possible pathways to the interior.

CONSEQUENTLY, It takes both things to experience the problem, and that's SOMETHING.

No, it is NOT. The smell OF COURSE will be much WORSE, and may be come noticeable much faster when really "bad," but the LEAK IS STILL THERE, whether you have a mild engine and dont smell it, or whether you have a wild setup and it is pungent enough that you do. THE LEAK IS STILL THERE. And remember, this, you CAN NOT SEE or SMELL CO. Even a mild engine that "you can't smell" may be leaking CO into the car.

 

[Snake]

I took a look at the trunk seal, found in the left and right lower corner area the weather seal gasket was not sealing tight, I could see light coming thought that area. I have reset the gasket [ do not see any light ] and need to road test to see if that helps/takes care of the fumes getting into my car.

what i said

 

[jbc426]

22dog22, did you find your exhaust's path into the car yet? If you can find a way to generate smoke inside the car with all the windows and truck close, you may be able to see some smoke escaping, and focus your efforts at better sealing those points.

 

[22dog22]

Hi jbc426 , take a look at post number 20, I still need to test drive to see that helped, also want to have my exhaust system pipes welded, have many pipes on with pipe clamps, want to clean up the underside anyway.