Back box just exploded!

[Sheffy]

I went to pull away, foot flat to the newly adjusted accelerator (wasn't getting full throttle before!) and then BOOM, exhaust blew up and is now split open along one of the seams. On the plus side it sounds louder!

 

What to do now? Replace whole exhaust? Grab a backbox from a scrappy?

 

Any help appreciated.

 

Cheers.

[RicardoM]

Buying a new rear silencer is the least of your worries. You must find out why a lot of unburnt fuel mixture got in there. Otherwise you'll witness a new explosion.

 

Probable causes:

• bad valve timing
• bad ignition timing
• too rich mixture!
• weak spark
• bad spark plugs

[Breezy_Pete]

Sounds like something some people would pay good money to achieve.

 

Could it not be that the (soot-filled) horse-hair-like wadding stuff inside the back box moved about enough to cause a major blockage, then a catastrophic pressure rise?

I've heard of that before somewhere, I think.

[RicardoM]

I don't believe in that theory. You need a totally sealed muffler with a solid cork.

Speaking of which, is it possible somebody played a prank on you? Meaning plugged or glued your exhaust? Maybe some sealing foam?

[KenONeill]

I don't believe in that theory. You need a totally sealed muffler with a solid cork.

Speaking of which, is it possible somebody played a prank on you? Meaning plugged or glued your exhaust? Maybe some sealing foam?

In which case the car just won't start!

 

A back-fire (where you're on the money about possible causes) certainly can split an old box along the seam line, where it's weakest.

[whitep]

Do you live near a tourist attraction and have any big bearded khaki wearing people in black toyota pickups waving flags with funny squiggles on it living nearby? Maybe they planted something overnight in your backbox?

[RicardoM]

Do you live near a tourist attraction and have any big bearded khaki wearing people in black toyota pickups waving flags with funny squiggles on it living nearby? Maybe they planted something overnight in your backbox?

Watching too much national TV can be hazardous for the brain.

[Sheffy]

I am a firm believer that it occured as a result of my month of part throttling due to the way the throttle cable had been incorrectly adjusted. As a result of all the partial throttle, some unburnt fuel was being deposited in my backbox.

 

Once the throttle cable had been adjusted and I began to make use of my new found power (HAHA!), the exhaust heated enough to ignite the unburnt fuel in the backbox resulting in an explosion.

 

Although I'm relatively useless when it comes to cars so it is merely a guess!

 

Thanks for the responses by the way. I have since replaced the backbox, but now need an exhaust hanging rubber as one is missing and causing the exhaust to foul on the chassis.

[KenONeill]

I am a firm believer that it occured as a result of my month of part throttling due to the way the throttle cable had been incorrectly adjusted. As a result of all the partial throttle, some unburnt fuel was being deposited in my backbox.

 

Once the throttle cable had been adjusted and I began to make use of my new found power (HAHA!), the exhaust heated enough to ignite the unburnt fuel in the backbox resulting in an explosion.

 

Although I'm relatively useless when it comes to cars so it is merely a guess!

 

Thanks for the responses by the way. I have since replaced the backbox, but now need an exhaust hanging rubber as one is missing and causing the exhaust to foul on the chassis.

Easiest way to sort that out is to go to a smaller branch of a chain, and play about with rubbers to get the right hang, then pay for the rubber you actually have on the car.

[Phil-E]

Too much power!