KABOOM, my muffler exploded

[bronco loco]

Ok, I need troubleshoot my problem, I was changing the shifting points on my Optishift. Went around the block and heard a loud explosion that even knocked the driver's side rear marker. I was hoping it wasn't the tranny and after looking under the bronco found the muffler wide open.
1.-I think shifting the points on the optishift is not related at all with the explosion.
2.-Last time I drove it, back in May the ignition switch begun to cut off. Can this cause the explosion?
3. There was some dieseling after I shut-off the Bronco yesterday, I think this may have something to do with the explosion.

So, besides buying a new exhaust, where should i start to troubleshoot?, thanks in advance.

 

[savage]

I'm not sure but when you shut it off when it was dieseling, it might have fill the muffler with gas or vapor , when you drove it the next time it might have ignited the fuel . my 2 cents

 

[El Kabong]

2.-Last time I drove it, back in May the ignition switch begun to cut off. Can this cause the explosion?

Yes. While you are driving or cranking the engine, if the ignition is off, unburned fuel/air mix can be pumped into the exhaust system. When the ignition reconnects it ignites normally within the cylinder, & when the exhaust valve opens, the flame spreads to everything in the exhaust system. The muffler is both the restriction & weak point, & gets pealed open like a tin can.

I had it happen once (To my dad's wagon which I had borrowed). It was a very loud boom. I had the coil wire disconnected while doing some work on it & forgot to reconnect it afterwards. I plugged it back in after cranking it while disconnected, started it up & BOOM! Then I bought him a muffler.

When I was a kid there were stories of guys turning the ignition off in gear then back on to blow out the mufflers so they'd have a loud exhaust system.

 

[BRONCROB]

Ha,I used to do that all the time on my old work truck on propane.Kill the ign. pump the throttle and turn the key back onKABOOM!!You may want to look for a bad connection in your ignition system.

 

[ugly74]

I used to purposely do that in my dodge....there was a heard of goats i had fun scaring the crap out of (i dont do that anymore), and its fun to drive past a golf course, and catch a golfer with that boom while hes on his backswing (i still do that).
They get pissed!

 

[roundhouse]

Yep. We used to do that on purpose

 

[bronco loco]

So i guess I'll start with replacing the ignition switch....

 

[AKwheeler]

If you are running air injection, it needs to be diverting to atmosphere on decelerations. If not, the rich decel fuel and extra air can cause the backfire.

 

[Pa PITT]

Ugly as I drive by the grass pool course I unroll my window and honk and wave at the guys not working ..

 

[M36]

When I was a kid there were stories of guys turning the ignition off in gear then back on to blow out the mufflers so they'd have a loud exhaust system.

Did that with motorcycles all the time. ;D

 

[Skiddy]

Ha,I used to do that all the time on my old work truck on propane.Kill the ign. pump the throttle and turn the key back onKABOOM!!You may want to look for a bad connection in your ignition system.

lol i used to do that too in my 66 truck, never blew a muffler though;D

 

[bronco loco]

If you are running air injection, it needs to be diverting to atmosphere on decelerations. If not, the rich decel fuel and extra air can cause the backfire.

Can you please elaborate. I have a holley 670 ta

 

[bronco loco]

No secondary air injection on my 1998 explorer engine with 670TA holley.