Can newer cars still backfire?

[Kevin]

Just tonight my wife and i were sitting out back, and some car drove down the big street which is three houses away.

It sounded like it was back firing while driving down the street.

It’s been a very long while since I’ve heard a car backfire.

I’m not even sure how they backfire, or what causes it?

So my question is, do cars still backfire?

I’ve got more questions too, just wait…

 

[wproct]

A lot of things can happen. There are all kinds of exhaust sensors, cam positioning sensors, and on and on that can cause a multitude of issues. I had one occur about 2 years ago that about drove me nuts, but it wasn't backfiring.

 

[Jeepnik]

No, they can't backfire. A backfire is a flame coming back out of a carburetor. What most folks call a "backfire" is actually a muffle explosions , where unburnt fuel is ignited by the heat of the muffler. You can still have muffler explosions and I hear them from time to time on newer cars that aren't properly cared for. But it takes some serious neglect to get that far.

 

[Dan in MI]

Generally no, injected engines don’t backfire, but some can.

I worked on the fix for 4.2L engines that backfired through the intake.

Any idea what kind if vehicle it was?

 

[tabora]

What most folks call a "backfire" is actually a muffle explosions , where unburnt fuel is ignited by the heat of the muffler. You can still have muffler explosions and I hear them from time to time on newer cars that aren't properly cared for. But it takes some serious neglect to get that far.

Also called "Afterfires". The cause is fuel ignited in the hot muffler, as stated above. Very rare with fuel injection. Small engines use an Anti-Afterfire solenoid to cut off the fuel supply in a carburetor to avoid this very loud phenomenon. Briggs & Stratton engines are noted to After-Fire very loudly if shut off when not running at full throttle.

 

[Watertender]

My dad had a 1968 Ford F250 that he used to make backfire. He would do it just to make people jump. One time he scared a bunch of girls who jumped and squealed and he got a big laugh from it.

 

[hittman]

Where’s GasGuzzler when we really need him? Or Captain America?

Yes, they can backfire I believe. Rare? Sure.
But bad ECM, fuel injector(s), modifications by Bubba …… never say never.

 

[txramfan]

Some people tune their cars, ones I've seen first hand while driving were imports, to make loud popping noises . I hear them often near my house, don't know why but people like to run bikes and cars late at night and some like to make their exhaust go bang.

 

[Joe Reilly]

And modern diesels aren’t supposed to puke out black smoke

 

[Dan in MI]

The 4.2’s backfired because of dirty fuel. The injectors sprayed the back of the intake valve. The fuel deposits would get so big the whole valve would look tapered instead of like a T. That mess would absorb fuel and and under right conditions backfire out the intake. It would usually do one large followed by two or three little ones then it would be good for awhile.

 

[Kevin]

And modern diesels aren’t supposed to puke out black smoke

And that’s another question altogether, if diesel engines will still run after turning them off. Dieseling? I think it’s called? I don’t think they do that anymore. I’ve had several new(er) vehicles and that’s not an issue.

 

[Kevin]

Generally no, injected engines don’t backfire, but some can.

I worked on the fix for 4.2L engines that backfired through the intake.

Any idea what kind if vehicle it was?

No I don’t know what type of vehicle it was at all. It was several blocks away. I heard it drove for even a few more after that. So I could hear it for at least 3/4 mile.

 

[WAYNO]

Something the kids do with their metric cars. Quite often I hear these rice or kraut burners popping away. They especially like doing this under overpasses or in tunnels.

 

[Dan in MI]

And that’s another question altogether, if diesel engines will still run after turning them off. Dieseling? I think it’s called? I don’t think they do that anymore. I’ve had several new(er) vehicles and that’s not an issue.

Once they went to electronic injectors it shouldn’t happen.

There is similar phenomenon where a diesel will run away uncontrollably.

 

[XUSNORDIE]

Where’s GasGuzzler when we really need him?

Something the kids do with their metric cars.

You both beat me to it......

 

[mirglip]

On carburated vehicles you could momentarily turn the key off and back one while going down the road in gear and they would pop. You can call it a muffler explosion if you like, but people have been calling it a backfire for 50 plus years.
Sometimes it would split a muffler at the seam.
A hot catalytic converter would prevent unburned fuel from making it downstream to the muffler.

 

[GSP7]

Yes new cars can back fire.

And electric cars can explode and burn for days and days creating glowbawl warming
:eek:

 

[s4s4u]

It would be rare to actually hear a backfire from any distance as the air filter would act like a muffler. Was the sound trailing a quick throttle-down?

 

[Mobuck]

"Small engines use an Anti-Afterfire solenoid to cut off the fuel supply in a carburetor to avoid this very loud phenomenon. Briggs & Stratton engines are noted to After-Fire very loudly if shut off when not running at full throttle."
I guess that part isn't working on our seed tender's 2 cylinder B&S. It doesn't have a variable speed-just governed speed and OFF. Each time it's shut off, there will be a 2-3 second delay and then POP POP. We get used to it but anyone not familiar with this 'after fire' does the 'duck and cover' act. :oops:

 

[Johnnu2]

If it was a truck, maybe it was Jake's Brake....??? I recently learned about these.
https://en.wikipedia.org/wiki/Compression_release_engine_brake

J.

 

[redhawker]

Back in ancient history, the 1970s, a friend told me he was riding with a couple of gang unit cops in LA when they pulled up on a group of bangers, stuck a baton out the window, and the driver turned the ignition off and then back on, causing a backfire. Of course, everybody scattered. Different world back then, bet you couldn't do that nowadays and get away with it. I told a friend about that, and he wanted to try making his car backfire, so he tried it and blew up both mufflers.

 

[el caminero]

On carburated vehicles you could momentarily turn the key off and back one while going down the road in gear and they would pop. You can call it a muffler explosion if you like, but people have been calling it a backfire for 50 plus years.
Sometimes it would split a muffler at the seam.
A hot catalytic converter would prevent unburned fuel from making it downstream to the muffler.

What really helps with the noise, is a leak in the exhaust pipe ahead of the muffler or catcan, and they can go bang from the momentary ignition-off, or multiple bangs on the over-run, in gear or not.

 

[Jakeintexas]

Yes. Although with FI cars it’s much less likely. But you still could get unburned fuel in the intake manifold and generate a sort of backfire.

I’ve had mustangs and a Harley where the after fire has happened and gotten the pops from time to time in the exhaust. Not that big a deal.

One failure mode I had on a 4.6L Mustang was a coolant leak at the heater hose juncture which would intermittently short out a coil pack. This would result in some serious popping in the exhaust manifold at certain RPMs as unburned fuel made it into the exhaust manifold and was subsequently ignited by hot gasses from other cylinders. Took a while to troubleshoot it.

So if this was excessive I’d suspect an ignition problem or maybe injector leak that was allowing unburned fuel to get into the exhaust. First guess would be a coil pack or spark plug.

 

[el caminero]

When i was a kid, the adults and older kids occaisionally called the engine intake backflame a backfire, or more specifically an engine backfire, and the one out the exhsust was just a backfire, tho some were sharp enough reports to be called crackfires, but its a funny language and we moved a lot and ive heard things that some others havent. I also get accused of making this stuff up...rich mixture (throttle closed) on the over-run will crackle nicely with an air leak into the system, the closer to the cylinder the better, but still works nicely after (downstream) the cat.

 

[Paul B]

Many long year s ago when I was between two wives I had a 1954 Mercury two door hardtop a guy gave me or free. He had to make out a bill of sale for one dollar as California wouldn't accept as a just given away car for nothing Seem the guy had backed into a telephone pole hard enough to custimize the rear of that car into a neat "U" shape. It burned more oil than gas and when going down one of San Francisco's steep hills in a lower gear the smoke cloud was just like a smoke screen in war. If it was a foggy night it took a while for the cloud to dissipate. You could also turn the key off when going down a hill and at the bottom when you turned the ignition back on it not only did it do the smoke screen but sounded like a Ma Deuce for about three seconds. It was about that time that I me and courted my second wife. She christened the car, "Old Smokey" and the name stuck. We married and the cars name stuck although the car ended up at a wrecking yard not too long after.
PJ