Car caught FIRE! Your guess on damages?

[H.M.]

Hey there,
My stock daily drive had a battery light that was flickering. I cleaned contacts, tightened connections, checked belts, etc but last night decided I needed a new voltage regulator which I ordered this morn on the way to work.

Leaving work tonight the battery is totally dead with no instrument panel, no lights, nothing. Jump started it and drove home (about 5 miles) in the dark. Started off ok but started running worse and worse, I guess cuz of engine computer/sensor/electronics that aren't working. About 300 yards from home it's really dogging down. So much that I pull to the curb at a stop light in case it stalls.

Someone taps on my window and says "fire." I hop out with an extinguisher, pop the hood and put out some small flames from around the catalytic converter. The cat and the exhaust pipe near it are red hot.

I wait for it to cool off and walk home. I'm going to get a truck and tow it in a little while but....what does anyone think the damages will be?

I'm guessing the cat heated up cuz the engine was passing incorrect fuel mixture to it or something like that. Aside from anything that melted cuz of the flames (which I think I got out pretty quick), what else is likely to be damaged? The cat? Any sensors maybe messed up cuz of what I did? Any electronics? I already have a voltage regulator on the way.

Where should I start looking?

[Ont1992ADL]

Something in y our exhuast system blocking it? thats a tough one? did you ride over a speed bump to fast recently? Other then that I cant see why your Batt terminals with have to do with that, poor contact is not going to cause a cat to start on fire...Unless some how by chance the voltages were to low and the ecu was infact sending some kind of bad signal to the engine cause a fuel mixture problem?..but even then thats hard to famish...IDK lol Good luck...Id look for wire damage...there is not much near the cat that could have really done that much damage...

[ExplodingCake]

Check you cat.

[F20A CB7]

nice job busting out the fire ext...

i would like a small 1. but ppl b like ahhhh thats ricey. funk that. its for emergencies like this.

where is urs located at??

[wed3k]

lol, i read about this in my text book but never heard anything of it.

First thing id do is check the battery and then the charging system. with the charging system not operating as it normally should, it can put an abnormal amount of stress on the engine.

the alternator will have a high duty cycle which will load the engine down.

now your converter caught fire because the PCM/ECU didnt have enough voltage from the battery and charging system so there was no air fuel mixture. it may have had enough power to let the injectors do work but not a strong enough spark which again was due to no battery voltage so the secondary ignition was weak.

rich mixture plus already hot cat = even hotter cat.

[H.M.]

Towed it in and am taking tomorrow off work for triage and, hopefully, repair.

I wonder if the cat is damaged from the high heat? (I've tried to block this out of my mind, but the pipes even toward the tail of the exhaust were red). And would a superheated cat be something that the car's sensor's would sense and adapt the engine for? Or would it just not clean out the exhaust as efficiently as it should?

There was so much heat under there that I'm expecting the dirt/grease/grime just caught fire. It was a nice gentle little flame, like a friendly little campfire under my car.

I keep the extinguisher under the seat but as I was reaching for it I was thinking "where is it?!?" But it was right where it should have been. Weapons, trauma kits, fire equipment - train with it until your actions are automatic cuz when the flag goes up my brain shuts down!

[xkjnboix]

kidde 2.5lb rechargable fire extinguishers are pretty cheap 25-35$ depending on where u get it from.

i would of course replace the cat and go from there. next i would reset my ecu ( pull that 7.5 radio fuse under the hood ) then check into the o2 sensor then fuel rail and injectors.

[Pazzword JDM]

hmmm, if it was an electrical prob and the sensors and such werent working for some reason then yes, it could have been caused by the wrong air/fuel mixture. sounds plausible, however, it sounds more like you cat couldve been clogged or maybe just a bad o2 sensor. you should replace your cat, check your o2 sensor and possibly replace that.

[Pazzword JDM]

lol, i read about this in my text book but never heard anything of it.

First thing id do is check the battery and then the charging system. with the charging system not operating as it normally should, it can put an abnormal amount of stress on the engine.

the alternator will have a high duty cycle which will load the engine down.

now your converter caught fire because the PCM/ECU didnt have enough voltage from the battery and charging system so there was no air fuel mixture. it may have had enough power to let the injectors do work but not a strong enough spark which again was due to no battery voltage so the secondary ignition was weak.

rich mixture plus already hot cat = even hotter cat.

this sounds about right.

[deevergote]

If the fuel injected into the engine wasn't burned properly, it could collect in the catalytic converter, which can easily get hot enough to ignite it. This very possibly could've turned out MUCH worse!

Get some pictures of the damage, and we'll be able to give you a better idea of what needs to be replaced.

[h22sparkle]

yeah definitely get pictures

[H.M.]

I finally got the car up on jacks and took a good look.

It seems like there is very little fire damage. A softball size section of the cat looks blackened, but other than that there are no visuals that there was a fire. So sorry, I got no gory pictures for you all. I'm hoping I got lucky on the fire part of the problem and nothing is affected by that except the cat, if that.

There's no physical damage to the cat or exhaust like dents or anything so I'm staying with the theory that unburned fuel collected and blocked the exhaust, then burned.

Assuming everything else operates ok, and the car adapts itself to whatever damage the cat suffered, I'm hoping I can run the car without problems until it's next smog check, then maybe I'll need a new cat cuz this one isn't running as efficiently as it should cuz of the fire. Good theory?

As to the rest...I got a new alternator and a new battery. Put the battery in, flipped igntion to START and everything lit up the way it should. That's good, right?

Unburned fuel should have evaporated by now so I'm assuming the exhaust is now clear. So next I swap the alternator, I'll check all the fuses, reset the ECU and then what else before I start it up?

Any ideas? Anyone? Bueller?

[blackice]

I would pull the cat off and check it out, i'm betting a chunk of the honeycomb crap in there broke off and is blocking the exhaust flow

[wed3k]

I finally got the car up on jacks and took a good look.

It seems like there is very little fire damage. A softball size section of the cat looks blackened, but other than that there are no visuals that there was a fire. So sorry, I got no gory pictures for you all. I'm hoping I got lucky on the fire part of the problem and nothing is affected by that except the cat, if that.

There's no physical damage to the cat or exhaust like dents or anything so I'm staying with the theory that unburned fuel collected and blocked the exhaust, then burned.

Assuming everything else operates ok, and the car adapts itself to whatever damage the cat suffered, I'm hoping I can run the car without problems until it's next smog check, then maybe I'll need a new cat cuz this one isn't running as efficiently as it should cuz of the fire. Good theory?

As to the rest...I got a new alternator and a new battery. Put the battery in, flipped igntion to START and everything lit up the way it should. That's good, right?

Unburned fuel should have evaporated by now so I'm assuming the exhaust is now clear. So next I swap the alternator, I'll check all the fuses, reset the ECU and then what else before I start it up?

Any ideas? Anyone? Bueller?

the cat still acts as a sponge, make sure you keep the engine off idle and clear that shit out.

[H.M.]

Finally got the new alt in, which was a PITA.

It was good advice to check the cat. I took it off and the back two / thirds of the honeycomb was fused into a ball of molten lava rock. I broke that out - it was pretty tough as the heat had turned it to glass and all it needed was some intense pressure to form itself into a diamond - and left the front third intact. Blew it out as much as possible and remounted it. I'll replace the whole cat before my next smog check.

I don't even think this was fire damage. I think it's just a 19 year old cat.

Started it up, let it run for 5 and nothing caught fire. Didn't even sound loud or weird or anything. I'm hoping the honeycomb that's still there acts as a sound muffler.

I think I got really lucky on this if no other damage shows up after a test drive. Caught fire, put it out, and it's all repaired for about 8 hours of labor and some parts.