I bought an 86 fiero gt a while ago, and after running it for short time I noticed a strange smell. I opened up the trunk/hood (in the rear) and my carpet has a burn hole in the same area as the muffler. All the heat shields are in place, and its a stock muffler, has anyone else had or seen this happen? And is there a solution other than removing trunk carpet to prevent fire?
Check for a hole in the muffler or pipes. Look in the area of your blower fan (right side of trunk) for electrical problems. Might also check the remote trunk latch mechanism for electrical problems. Not much else back there that would cause a fire.
The trunk light wiring would be in the same area- I disconnected mine because having the light shine directly in your eyes does not improve your ability to see in the trunk in the dark...If the wire is hanging back there- or has worn thru the insulation- then that may be the cause.
I actually melted the back of my carpet after installing a 3800 SC Series III with lots of goodies and a custom exhaust. I did two things to correct the situation. The first one was to install a SS heat shield between the trunk and the muffler. The second was to insulate the entire trunk. No problems since then and it has been better than five years of running time.
Ya, the heat shield is there, maybe I should find a better one. I'm pretty sure its not the light, the burn area is a little low. It has actually burnt through the carpet, and left a big black ring of unburnt carpet just waiting for me to run the engine again. The muffler is new, so no pinholes in it, and the burn area is right in line with the muffler. Not sure what kind of insulation or material to put in there to keep a new carpet from burning.
[This message has been edited by v6_fiero (edited 05-01-2017).]
Ya, the heat shield is there, maybe I should find a better one. I'm pretty sure its not the light, the burn area is a little low. It has actually burnt through the carpet, and left a big black ring of unburnt carpet just waiting for me to run the engine again. The muffler is new, so no pinholes in it, and the burn area is right in line with the muffler. Not sure what kind of insulation or material to put in there to keep a new carpet from burning.
Maybe the new muffler was mounted a little too close to the trunk?
It has actually burnt through the carpet, and left a big black ring of unburnt carpet just waiting for me to run the engine again.
Ya, the heat shield is there, maybe I should find a better one.
Something has obviously been altered from the factory setup for this to be occurring. This is definitely not a common problem. As a matter of fact, I can't recall in all the years that I've been here that anyone else with a stock Fiero has ever reported this issue.
[This message has been edited by Patrick (edited 05-01-2017).]
The muffs too close to your trunk or he didnt weld it up good n u got a lil leak. Wait till the exhaust is cold n start it up n feel for an exhaust leak
Ya, the heat shield is there, maybe I should find a better one. I'm pretty sure its not the light, the burn area is a little low. It has actually burnt through the carpet, and left a big black ring of unburnt carpet just waiting for me to run the engine again. The muffler is new, so no pinholes in it, and the burn area is right in line with the muffler. Not sure what kind of insulation or material to put in there to keep a new carpet from burning.
I used a foil backed, sound attenuating insulation in my trunk along with the new SS heat shield between the muffler and trunk. The insulation was Dynamat Pro and is available from Second Skin Audio. Several similar types on insulation are also available from different sources. IIRC, it took about 20 square feet to completely cover the trunk area under the carpet.
Something else to look for. The older pellet type catalytic converters(GM 73-86 )(my 85 originally had a pellet type) were notorious to have the pellet bed rot out. This will allow the pellets to move down the exhaust and the first place for them to collect is the muffler. Turning it into a converter. On older full size Gms, seen this happen and the muffler would get hot enough to melt the foam in the back seat on the other side of the floor from the muffler. Look to see of the muffler has a blue hue to it. Also you can pat it with your hand. If it sounds like it has sand in it, it most likely has catalyst in it.
If your cat has rotted, you can get a newer honeycomb style.
IIRC (I'm in central Illinois), even California has a replacement exemption for pellet bed converters that have gone bad, specifically because the old converters were (A) crap and (B) no longer available.
The older pellet type catalytic converters were notorious to have the pellet bed rot out. This will allow the pellets to move down the exhaust and the first place for them to collect is the muffler. Turning it into a converter. On older full size Gms, seen this happen and the muffler would get hot enough to melt the foam in the back seat on the other side of the floor from the muffler.
That's quite interesting... and potentially quite dangerous!
There is a gap between the muffler and the heat shield, but only about a half inch gap between the heat shield and trunk. Maybe to close. I think I will pull the carpet until I find the issue. The muffler looks new, Im gonna try to attach an image.[img]
If you're going to use Photobucket (which sucks), you've got to learn how to link to an image properly. It also helps if you re-size/re-compress the image so that the file size is 300kb or less (and no more than 1024 pixels in width). Then an icon to click isn't required.
[This message has been edited by Patrick (edited 05-07-2017).]
If you have a converter where your muffler is now, there is no way to get the catalyst out without cutting open the muffler. Unless it is a delta or open baffle. Any of the normal baffle will hold the pellets unless it melts open. I can only assume you have a stock type muffler. If that is the case the first baffle is going to be at the bottom or middle. You may need to pry the muffler away from the rear firewall/trunk to see the body of the muffler to determine if it has discolored.
Rhodium is used more now because it works as a catalyst at lower temperatures, but very rare. There were a few years that Mercedes could not get their emissions down enough, so they made an agreement with government regulations , that they used rhodium in a coating on their radiators. It was the idea that the incoming air would have more pollutants than the amount that the cars needed to pass. So if they cleaned up the air from the cars they were following, the total emissions from the primary car passes. Yes it is illegal to replace those radiators with ones without the emissions coating.
The older catalyst work at much higher temps. (not to spec) think in the 500 degree range or better is where they start to light. Up to hot enough to make steel glow when something isn't right. Un burnt fuel makes them nice and cherry. There used to be crayon/markers but I haven't seen any in over 20 years. They would melt at different temps and you could tell if an area was normal. They are like the ones used on railroads and heavy machinery to check for bearing journal overheat.
However. See if you can find someone with an inferred thermometer. Try to get different temps from different points of the exhaust. Least that way you can make sure it isn't a problem upstream. You said you recently bought this? Do you know how long it sat before? If it was running bad enough, dumping a lot of fuel, even without a converter, you can overheat the exhaust.
[This message has been edited by cmechmann (edited 05-08-2017).]
