I replaced my distributor this weekend and for some unknown reason I did not re-connect the coil wire after the job was done.
So.....early this morning I got in my car and tried starting it and I noticed after 5-6 seconds of cranking it wouldnt start.

After realizing my error I re-connected the coil wire and then tried starting it again. As soon as it started to crank it let out the BIGGEST engine backfire I have ever heard! It didnt sound like a gunshot....uh, it was more like a CANNON!

Anyways, I drove it to work today but I was wondering what kind of damage a SEVERE backfire can do to a 2.8 Fiero?

Thanks, Kit

You can break up the cat element, but ordinarily if it does, it will just spit the loose pieces out the tailpipe. If you dont notice your engine getting sluggish all of a sudden, dont worry about it.

Having punched cats out before, it would take QUITE the explosion to destroy a cat. Unless its already old and very brittle.

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As stated above (regardless of the amount of explosion) to answer in simple terms, yes a backfire can break the guts of a cat apart. I forget what it is made of (ceramic is coming to mind), but it it did break apart you should hear something rattling inside if you shake it around. Obviously, when the car is cooled off, jack it up, grab the cat, and shake. If it sounds like something is in there, you might have damaged something.

If you have more info, please add to this. From what you asked, I am not sure what we are diagnosing.
Oh, and if you need to replace the cat,
http://rodneydickman.com/ca...g/index.php?cPath=51

I'm not going to say this is the cause but its hard to explain otherwise: I bought a new 2.8 v6 crate engine for my car. Long block so it already had the new heads installed. I checked the torque on the head bolts before assembly. All good. Assembled & installed engine with a new distributor etc etc... After install, I went to crank it for the first time. BAM!! Big backfire. Had the distributor out 180*. Fixed that and then started the car for the first time. Noticed water shooting out the bottom of head. After scratching my head a bit and a few choice words I disassembled the engine and this is what I found. Don't know what else could have caused this but the big backfire, the engine had never been cranked. Put some new gaskets on and its been fine.

Can also blow the intake gasket w/o causing a water leak but causing a compression leak very hard to detect.

Backfire is fire from the cylinder bore, valve, the intake and up threw the carb or the throttle body. You are describing a cook off of unburnt fuel that accumulated in the catalytic converter. And yes it can damage the converter. One time maybe not. We used to turn off the ignition , then turn it back on to get this explosion when I was in high school (60's). This was stopped about the time of the introduction of the converters. Raw gas there was dangerous because of the temps in the converters.

quote Originally posted by josef644: Backfire is fire from the cylinder bore, valve, the intake and up threw the carb or the throttle body. You are describing a cook off of unburnt fuel that accumulated in the catalytic converter. And yes it can damage the converter. One time maybe not. We used to turn off the ignition , then turn it back on to get this explosion when I was in high school (60's). This was stopped about the time of the introduction of the converters. Raw gas there was dangerous because of the temps in the converters.

An old friend of mine back in University days use to turn his ignition off & on periodically in his '72 AMC Maditor as you decribe while driving down the road - to scare pedestrians, etc., etc. Occassionally this would split open a part of the exhaust system which he simply weld back together back in his driveway. Needless to say the car was pretty much a piece of junk.....

It occassionally made some monster back fires!

Topic: Can backfires damage an engine or maybe the cat???

i guess if a cat with just 1 life left is running behind your exhaust in the exact time you get a backfire . i bet the cat will be damaged


ok real danger is the map . even 1 backfire can kill the mapsensor and thats just not fine.
And if unburned fuel ignites in or before the catalyt u can bet the ceramic structure gets a damage

quote Kitskaboodle:... I was wondering what kind of damage a SEVERE backfire can do to a 2.8 Fiero?

Starting the car after coil wire was loose.

Old muffler.

[This message has been edited by 30+mpg (edited 02-02-2010).]