i think your having a reverse draw problem. Lots of things can effect that.
Is your firplace hard to get started?
If your house is tight, it could be pulling air down the chimney, if the room that the fireplace is in is a negative pressure area, its naturally going to want to neutralize it. The chimney becomes the supply for the room, making it stink.
The other possiblitly is your chimney isnt tall enough, or you have someting with in 10' of the top of the chimney, like a tree, or a roof line or something, causing downdrafts.
Bottem line, a properly functioning chimney will not smell. Either the chimney is at fault, or the house is.
There is a limited possibilty that the fireplace has a bad design, like to big of chimney for the size opening of the fireplace, or vise versa.

I still cant seem to get it.

I vacumed out the entire fireplace, it was good for a few days, but we just got huge winds and its raining/icing/freezing rain right now, and my entire house is back to smelling.

Here are some things i have been thinking.

1.)I have had the flu open just a touch. With big winds this may be the cause of the smell being pushed down and into the house.
2.) I close the flu and it seems to smell even worse. The floor vent leaks and I havn't been able to seal it. If the flu is closed, big winds are going to push tons of air into the fireplace, its going to hit the flue and all the fireplace walls which are black from years of use, adn since it has no where to go it comes into the house? Thats why I thought maybe I should crack the flu so it can escape.

I really don't know what the correct configuration should be for someone with a floor vent. I can't seem to find much info on the web regarding floor vents, and the people that came to sweep the thing were clueless, and the guys that removed the gas logs, well that was before it smelled.

Can someone help me?

This is not just a faint smell, its terrible!

Call a chimney expert. YOU HAVE A REVERSE DRAW CHIMNEY. period.

Here is a article i ran across this morning.

here is the link that i copied and pasted it from, it should answer all your questions..

http://chimneysweeponline.com/library.htm

Q: We just bought a newer, tightly built house, and are grappling with a rather strange problem with our fireplace. We might expect to smell a little smoke when we have a fire going, but we don't. We notice a strong smoke smell that comes from the fireplace when we're NOT using it. We had the chimney cleaned and it didn't help (maybe our Sweep didn't do a good job?). Do you have you any idea why our fireplace smells so smokey, and what can we do about it?
Lionel

A: Wood-burning fireplace chimneys smell smokey whether they've just been swept or not, because no matter how thoroughly your Sweep brushes the flue, he can't possibly remove every trace of soot and soaked-in creosote. Even if he were able to sand-blast every microscopic remnant of wood smoke deposits out of the flue, the very first wood fire would deposit a fresh layer, and the pungeant, smokey odor would return. So the real question isn't why your fireplace smells smokey: the question is, why is the odor entering your house?
First, let's consider the fact that even the most tightly constructed homes have many, many openings (or air pathways) to the outside. There are intended air pathways, such as ventilation intakes, kitchen & bathroom exhaust fans, clothes dryers and combustion appliance flues, to name a few. There are also numerous unintended pathways, such as electrical, plumbing, cable and ductwork penetrations, leaky windows and doors, unsealed building cavities, ventilated flashings around vents and chimneys, etc.
Companies that perform air infiltration testing express the total of all these air pathways as if they were put together into one big hole. It is not uncommon for a supposedly "tight" house to have an air pathway total of over 400 square inches, the equivalent of an open window measuring 20 inches square! At any given moment, air is transferring out of the house through some of the pathways that make up this 'window', and replacement air is entering through whichever of the others offer the least resistance.
The biggest air pathway to the outside in most houses is the fireplace chimney. A fireplace chimney can allow airflow in both directions. When in use, a fireplace chimney is a powerful evacuating force: the chimney updraft created by an open fireplace fire can move hundreds of cubic feet of air per minute out of the house, in many cases more air than the other pathways combined can supply! This is why you don't smell the smokey odor when a fire is burning in the fireplace: it is only when the fire dies down, and the updraft diminishes to the point where evacuation from other sources overcomes it, that the airflow in the fireplace flue reverses and the odor returns.
So what other forces are evacuating air from the house, causing makeup air to be pulled in through the fireplace chimney? At any given moment, a combination of evacuating forces might be at work. Some are mechanical, as is the case with unbalanced central heating and air conditioning systems, exhaust fans and clothes dryers. Some are from natural causes, as when the wind blowing against the house creates positive pressure on the windward side and negative pressure on the leeward side. Some are thermal, like the rising exhaust gases in woodstove, furnace or water heater flues.
Another example of thermal evacuation is the so-called "stack effect". Heated air has lower density than cold air, so the warm, buoyant air in your house wants to rise through the roof, while the cold, heavy air in your unused fireplace chimney wants to flow downward into the house. If there are pathways in the upper stories or roof to allow the rising room air to escape, the warm air will flow up and out of the house and replacement air will flow down the chimney and in through the fireplace. The stack effect is more pronounced in taller, leakier houses and in houses with cold chimneys (like chimneys on outside walls, exposed to outdoor temperatures for their entire length). Rainy weather also accelerates the stack effect, because the wet air entering the chimney is heavier than the dry air in the house.
Whatever the cause, whenever air travels to the outside of the house, an equivalent amount of air attempts to enter somewhere to replace it. If the chimney offers the path of least resistance for the makeup airflow, the smokey smell of wood creosote will enter the house along with the replacement air.
What can you do to stop your house from using the fireplace chimney for makeup air? All you need to do is create enough resistance to the flow of air down the chimney so that the other air pathways will provide less resistance to nature's tendency to equalize air pressure inside and outside the house.

If I close my glass doors and close the damper on my masonry fireplace, the smell does not enter the below-grade family room.

You may be able to add a set of glass doors or add another damper to the top of the chimney cap. Either way, you will be trapping the chimney air and creating a difficult path for the smelly air to travel (creating enough resistance to air flow as the article mentions).

so this guy wants to sell me an air make-up kit. this kit costs 1500-1900$$$ holy cow! we do have new windows and i think that the house is fairly tight, but $1500!!!@#@#$ holy cow.

we definatly are having issues with pressure outside and pressure inside not being equal but i just can't seem to spend that much money on this thing. that sounds crazy.

anyone ever heard of this, is it an over engineered solution?

thanks

probably an exterior chimney, right? this is why you don't build chimneys on the outside of homes; the center is where they belong.

My masonry fireplace is an exterior chimney and I do not have odor issues with the fireplace as long as I keep both the vent and glass doors closed.

MRedding: Why don't you try one of the recommendations from my 2/26 post. The chimney cap with damper may be a DIY job - a chain hangs down the chimney and you pull it to open/close the damper. This in combo with your existing damper may trap the smelly air between the 2 dampers.

We have a three flue external wall brick/tile lined chimney on one side of the house, it serves two fireplaces and one airtight stove, each with its own flue/chimney. We've used all but the fireplace in the M Bedroom many times over the past 18 years and have found of late that we have a smell problem, somewhat at described in this thread. We're having the airtight insert in the livingroom removed and are putting a "Lock-tight" cap on the top of that chimney. We'll also have the chimneys cleaned. The normal damper is not a good fit, they never are. The Lock tight is operated by a chain hanging down the chimney, and operates like a storm-door damper. This is fine for an "open" fireplace, not for one with an insert. The fireplace in the M bedroom, which has never been used has fiberglass insulation stuffed up around the damper to prevent smoke from coming back down the chimney when one of the other units are in use, a Lock-top would work there, but as we don't use it, why spend the money. Money? The Lock-top installed is about $250. Not cheap, but if you install yourself you can save $50 or a bit more. The airtight in the basement has been disconnected and I have covered the chimney entry hole (there is a horizontal tile that runs into the basement wall to reach the vertical tile lined chimney. I can say on a cold day, when I had removed the airtight stove pipe there was a strong cold wind blowing down the chimney and it had the old fire smell. The airtight should seal the chimney off, but of late it hasn't done the job. I think I'll leave it disconnected and if we have a power outage I'll connect it just long enough to get us back on the line. While I've enjoyed the wood fires, and plan to have a few in the living room fireplace (with the Lock-top damper) I've decided the smell is too much at times, so no more "heating" with wood for me, at the cost we pay for hardwood in NJ the savings are small or none, especially when the cleaning and other maintenance are added in.

I think MSG hit it negavive pressuer the fire place location is below the nuetral pressuer plane of the house excuse me while a laught babout the damper solutions and glass doors
First of all dampers common fire place danpers are not air tight they leak the problen is there are leaks above the nuetral pressuer plane Start looking at your upstairs area first is leaking windows above the pressure plane bath fans recessed lights but the biggest culprit are attic pulldown stairs and attic hatches Seal up the leaks above reduces air comming down that chimney another factor is heat loss in the attic ceiling inadequate insulation of missing poorly placed insulation allows heat to escape what is replacing that heat is cold below and cold comes in with cold air from the path of least resistance your chimney ITs a combination of dfrsts losses above and heat losses creating the vacume below. one approach is to try to reduce flow in the chimney with glass doors and chain dampers but that does not correct the cause of your problems leakage above if this is occuring imagine the heat lossed=s your are experiencing whithout even knowing it you may need nore insulation in that ceiling or correct poorly placed insulation sealup and insulate you attic acceses the problem originates above the fireplace opening

I bring this one back in an effort to get my experience seen/shared. I posted similar information against a current post of the same subject.

I note here that I also had a Lock-top chimney top damper installed prior to having the chimney apron repaired. It appears my problem was not specifically related to a downdraft in the chimney, which the Lock-top would/did fix. The benefit of the Lock-top to stop loss of condition air remains but it appears it did not make a major contribution to stopping the fireplace smell. The bottom update is to another thread in which I talked about having my roofer repair the chimney apron cement, which he did and which did not immediately stop the smell, but I was willing to wait and see if having water incursion stopped would allow the any dampness to dry out and thus for the smell to stop, this seems to be the case, have my "fingers crossed".

From other post: Update, two periods of rain, the latest still going on as part of the North-Easter heavy rain hitting the NE Coast and the smell has continued to diminish. So my lesson learned: check, or have checked, the integrity of the chimney cap. In our case it is a cement apron covering the area between the three flues exiting the common chimney structure (about 4feet wide by 1.5 feet deep). As reported the chimney sweeper told me the apron had large cracks (finger width) and would let water into the chimney structure (not the flues as they had their own rain caps/hats).