Fumes...yuck...air pump maybe? 72 fury wagon

[MBar]

I get what seems like exhaust fumes. Back window is closed. Other Windows open or closed doesn't matter. I read the thread on wagon exhaust and mine appears to be correct making a 45 degree to the side and turned down.
I inspected the exhaust pipes and muffler and manifold flanges and nothing visible or heard.. no ticking of exhaust leak... so I'm wondering if a fault in the air pump system could be the cause. The engine is a 400. ....

 

[NY69]

How's your trunk seal, no gaps?
Or the trunk bottom, everything sealed?

Converting your Fury to ev will definitely fix the problem

 

[CBODY67]

On the air pump systems, the air pump output goes to its various places under the hood via rubber hoses and valves. Other than the external plumbing which GM and Ford used, I recall that Chrysler put their air to the exhaust manifold via the front of the manifold itself, rather than to the individual runners in the exhaust manifold? BUT if one of the "one-way valves" goes bad, it can let exhaust gas get past these valves and further upstream toward the pump and diverter valve. Usually, though, some additional exhaust noise is evident when this happens, plus the rubber itself can melt/degrade from the exhaust heat it was not designed to tolerate.

The one-way valves can be somewhat "common" between the OEMs, but the diverter valves and items upstream might not be.

The OTHER thing is that if the engine is properly tuned, hydrocarbon output should be greatly decreased from prior times, which also minimizes any smells out of the exhaust system, by observation. As a check, with the engine at full operating temperature (after driving about 10 miles on the freeway), you can momentarily place the palm of your hand in the exhaust output for a few seconds (it will be HOT). Then immediately compare the smell from your hand to that which is getting inside the car. Same or different? Using that method is how I used to verify the carb idle mixture on my cars, plus the idle speed in gear for smoothness. So I know it can work, but only one exposure between handwashings, as the smell lingered a while. Also, be sure to fully wash your hands afterward, so any "nasties" in the exhaust gas aren't absorbed into your skin!

What about any engine/transmission oil leaks which might be hitting the hot exhaust system, generating "smoke or smells" which can get into the passenger compartment? Just curious.

Please keep us posted on your progress,
CBODY67

 

[MBar]

On the air pump systems, the air pump output goes to its various places under the hood via rubber hoses and valves. Other than the external plumbing which GM and Ford used, I recall that Chrysler put their air to the exhaust manifold via the front of the manifold itself, rather than to the individual runners in the exhaust manifold? BUT if one of the "one-way valves" goes bad, it can let exhaust gas get past these valves and further upstream toward the pump and diverter valve. Usually, though, some additional exhaust noise is evident when this happens, plus the rubber itself can melt/degrade from the exhaust heat it was not designed to tolerate.

The one-way valves can be somewhat "common" between the OEMs, but the diverter valves and items upstream might not be.

The OTHER thing is that if the engine is properly tuned, hydrocarbon output should be greatly decreased from prior times, which also minimizes any smells out of the exhaust system, by observation. As a check, with the engine at full operating temperature (after driving about 10 miles on the freeway), you can momentarily place the palm of your hand in the exhaust output for a few seconds (it will be HOT). Then immediately compare the smell from your hand to that which is getting inside the car. Same or different? Using that method is how I used to verify the carb idle mixture on my cars, plus the idle speed in gear for smoothness. So I know it can work, but only one exposure between handwashings, as the smell lingered a while. Also, be sure to fully wash your hands afterward, so any "nasties" in the exhaust gas aren't absorbed into your skin!

What about any engine/transmission oil leaks which might be hitting the hot exhaust system, generating "smoke or smells" which can get into the passenger compartment? Just curious.

Please keep us posted on your progress,
CBODY67

I just noticed at least one vacuum hose toasty and off...heading to O'Reilly for hose and see what valves they carry... I'm happy to have found something to chew on and I'll update in bit .. thanks so much

 

[thrashingcows]

I agree with NY69...could be old worn gasket around the tailgate that is allowing exhaust fumes to move inside the cargo area.

Try this....when driving open the floor vent(s) and see if the exhaust smell goes away, since your pressurizing the cabin with forced air and "should" keep the fumes out. I do this if I have the rear window down a bit in my wagon, seems to work pretty good.

 

[MBar]

I agree with NY69...could be old worn gasket around the tailgate that is allowing exhaust fumes to move inside the cargo area.

Try this....when driving open the floor vent(s) and see if the exhaust smell goes away, since your pressurizing the cabin with forced air and "should" keep the fumes out. I do this if I have the rear window down a bit in my wagon, seems to work pretty good.

I had seen that in the wagon exhaust thread... but my vent pulls are stiff and won't open so I have to check them out as well...
I do get the fumes when just sitting in the driveway but yeah I think the seal could be an issue too....sigh.....

 

[1970FuryConv]

Hi Mario. This may not be exactly the same, since the car was not a station wagon, but I had one with a slight blockage in both mufflers of a dual exhaust system. What happened was: the car would run fine for about 30 minutes and then the exhaust fumes would start to back up behind the mufflers and find a way out into the passenger compartment. A few minutes after that, the car would start to run badly at speeds above 45mph.

The test is to put a vacuum gauge on intake manifold vacuum at idle and then increase engine speed using the throttle linkage. Watch the needle on the vacuum gauge. If it starts to drop toward zero, you may have an exhaust system blockage. Generally vacuum should be 17 – 21 HG at idle. 17 – 21 HG is best case figure. If your idle vacuum is well below that, you may also have an exhaust system blockage. The 360 engine in my 1972 Fury is worn, but has steady idle vacuum of 15.5 HG with no exhaust system problems. If you idle vacuum is significantly lower, might be time to see how it runs with the mufflers removed. Hope this helps, Ben

 

[CBODY67]

Hi Mario. This may not be exactly the same, since the car was not a station wagon, but I had one with a slight blockage in both mufflers of a dual exhaust system. What happened was: the car would run fine for about 30 minutes and then the exhaust fumes would start to back up behind the mufflers and find a way out into the passenger compartment. A few minutes after that, the car would start to run badly at speeds above 45mph.

The test is to put a vacuum gauge on intake manifold vacuum at idle and then increase engine speed using the throttle linkage. Watch the needle on the vacuum gauge. If it starts to drop toward zero, you may have an exhaust system blockage. Generally vacuum should be 17 – 21 HG at idle. 17 – 21 HG is best case figure. If your idle vacuum is well below that, you may also have an exhaust system blockage. The 360 engine in my 1972 Fury is worn, but has steady idle vacuum of 15.5 HG with no exhaust system problems. If you idle vacuum is significantly lower, might be time to see how it runs with the mufflers removed. Hope this helps, Ben

ANY exhaust system removal of suspected parts should be for diagnostic purposes only. Many states have statutes requiring the end of the exhaust pipe be past the passenger compartment. On station wagon-type vehicles, that would mean the rear bumper, I suspect. No issues with removing the parts for diagnosis, just not driven.

The roof air deflectors are supposed to help keep air flow over and behind the car so that exhaust fumes are not sucked into the passenger area and the low pressure area behind the car, as it move down the road. Some of the popular ones were mounted to the rear roof pillar vertical areas, which put "side air" to the back of the car.

Just some thoughts,
CBODY67

 

[MBar]

SOLVED!!!! Went to O'Reilly and asked them for all emission parts and there were 3: the pump, the canister filter and the check valve... haven't replaced the canister filter (how?) But I did change the check valve. Yay!!! No more Fumes! Now I can drive it. Btw I tried testing the valve by blowing in both directions and it seemed to be ok because it's just a one-way valve. It actually felt less resistance than the new one but I swapped it anyway. 20 bucks well spent. Thanks to everyone as usual.... if I don't get the answer, I get the sense of community and feel inspired. LOVE THE FORUM

 

[MBar]

I have an update... It's been quite a while. The smell did not go away after all... I hardly drove it because of that, though she got a nice fresh paint job. But I do have great news... Most recently, it occured to me to check the timing. Yeow!! It looked to be at least 20 degrees advanced! I set it to around 8 and it runs nicely. Made a HUGE difference. Does that make sense?

 

[CBODY67]

If the check valve changed the situation, ALSO check the piping between where it is and the tubes where it goes into the exhaust manifolds themselves. The purpose of the check valve is to keep hot exhaust gases from flowing into those tubes, not otherwise. If the hot exhaust gases flow into the piping, it can deteriorate those tubes at the exhaust manifold from the inside out. When they can eventually fail, it can mean an underhood fire. Saw a lot of that on mid-'80s Chevrolet 5.0L V-8s, with their plastic switching valves. After the check valves went away, the plastic melted.

Initially, the Chevy AIR tubes were cad plated, then a thin layer of chrome made them look nice, but in the end, it was that thin layer of chrome plate that was holding them together before they failed. So please check those tubes at or near the exhaust manifolds. Might get a wrench and tap on them, looking for a "thin" sound rather than a "solid" sount, possibly.

Just some observations,
CBODY67

 

[Boydsdodge]

On timing. Your engine was liking the 20, quick starts, cleaner smooth idle, lower engine temps. At a lower timing you will have richer exhaust, when you retard the timing, your idle went down, then you will need to turn idle screw to increase idle speed.
Check your timing at 3000 RPM, your 400 should be 36 deg total. Without vacuum hose hooked up.
On the exhaust smell, it could be running rich, choke stuck, time for carb rebuild, tuneup.
My wagons rear window seal on tail gate is shot and the bottom of the door has two holes from rust. You dont see unless you lift the floor to door flap. If I have windows up I have to open vent slightly to pressurize cabin.
Your air pump won't have anything to do with exhaust in cabin, unless it has come away from manifold, and that would be noisy.
I say it is a sealing and tune problem.
P.S. I saw your wagon at Spring Fling.

 

[Toolmanmike]

I was getting fumes up through my steering column through a bad 50 year old lower column seal.

 

[1970FuryConv]

I have an update... It's been quite a while. The smell did not go away after all... I hardly drove it because of that, though she got a nice fresh paint job. But I do have great news... Most recently, it occured to me to check the timing. Yeow!! It looked to be at least 20 degrees advanced! I set it to around 8 and it runs nicely. Made a HUGE difference. Does that make sense?

View attachment 574665

Did the smell go away after you reset timing?
Were you getting knock with the timing so far advanced?
I have read that too much advance can make the engine smell acidic because of too much NOX. Have not experienced that problem. I have experienced smell of unburnt gas with too much timing retard, but should not be a problem with too much advance.

 

[MBar]

Did the smell go away after you reset timing?
Were you getting knock with the timing so far advanced?
I have read that too much advance can make the engine smell acidic because of too much NOX. Have not experienced that problem. I have experienced smell of unburnt gas with too much timing retard, but should not be a problem with too much advance.

I wasn't getting pinging.. smell seems to have mostly gone... I don't drive it much and keep it in storage so next time I run her I'll do a thorough sniff test. Trying not to be affected by wishful thinking as I was with that valve...