Truck backfires

[justletmein]

Ok so this truck is headed to fish camp to rust out and die. It's got headers and catalytic converter is punched through so should be clear. The header gaskets were bliwn out so I replaced them, now it's backfiring while idle. I patched an exhaust pipe hole with fiberglass patch gizmo and reseated the plug wires but haven't checked plugs themselves but I'll do that tomorrow. I'm supposed to drive it to the coast Tuesday so this backfire thing is screwing up my timing.

What other simple things should I check to squash this real quick? I can do plugs and easy stuff.

https://youtu.be/tk9nvlQHOEE

[Big Lee]

Sounds like tin being struck. And not a misfire. Could be my phone audio.... what year, make, model, engine?

[Pipeliner1]

Sounds like something hitting something metal?

[justletmein]

It's a 1996 Dodge Ram big V8. Seems backfirey, burat of exhaust out the back when it happens. I'm wondering if something goofy is going on with that punched out converter. It was fine before I replaces the exhaust header gaskets so not sure how that ties in other than the gas has been sitting in it close to a year. I'll get a better vid tomorrow, don't wanna tick off the neighbors now.

[Big Lee]

If it was fine before you made the repair. Don't get too crazy with it. Make sure a bolt or tool is not in the fan shroud. Try to isolate the exact location.

[RifleBowPistol]

Sounds like either the plug wires are crossed up, if it has a distributor, or you have some other problem. It sounds like a exhaust valve may not be opening. What I hear, is a cylinder firing back into the intake. Either the plug wires are crossed up and it's firing a cylinder at the wrong time, or a exhaust valve is not opening, so the burnt mixture is going back out the intake valve the next time it opens. If the plug wires are not crossed, I would say it has a valve train problem, bent or smashed/split pushrod, broken exhaust rocker arm, collapsed exhaust lifter or wiped out exhaust lifter roller and cam lobe.

I keep hearing the Dodges have all types of lifter problems, if it's not a crossed plug wire, I would be checking the valve train. I do not know when Dodge stopped using distributors and went coil on plug. A buddy of mine has two 01 Dodges, they both still have distributors. Those are the newest Dodges I have worked on, other than fwd junk Dodge cars.

The noise sounds a lot like a old small block Chevy, when they eat up a exhaust lifter. They get air and fuel in the cylinder, then it is fired by the ignition system, but then the exhaust valve does not open, so the burnt mixture has to go back out the intake valve the next time it opens. So you hear a pop in the intake manifold when it does.

[Hart8]

I'm no help,but it did remind me of a funny backfire story!
Had an old Chevy suburban with a 454 in it.You had to kill it in drive,then put it in park;or it would backfire everytime.Headers/duals..It was loud as hell!
Home depot parking lot.Mexican dude bent over in his trunk rearranging some stuff,as to get all his bags in it..I put it in park,killed it;and BOOM!!!! He must've smashed his head on the trunk,cuz he came up rubbing his head,and shaking a hammer at me�� I apologized several times.

[justletmein]

I don't have an update yet, but did want to clarify that when under load there's no backfires. So for example if I hold the brakes and rev it up to maybe 1.5krpm there's nothing it just chugs. If I leave it in park and rev it'll still spit backfires but less of a pop.

I'm no help,but it did remind me of a funny backfire story!
Had an old Chevy suburban with a 454 in it.You had to kill it in drive,then put it in park;or it would backfire everytime.Headers/duals..It was loud as hell!
Home depot parking lot.Mexican dude bent over in his trunk rearranging some stuff,as to get all his bags in it..I put it in park,killed it;and BOOM!!!! He must've smashed his head on the trunk,cuz he came up rubbing his head,and shaking a hammer at me�� I apologized several times.

LMAO

[6.5 shooter]

Sounds like it already died.

[Bucknaked]

I don't have an update yet, but did want to clarify that when under load there's no backfires. So for example if I hold the brakes and rev it up to maybe 1.5krpm there's nothing it just chugs. If I leave it in park and rev it'll still spit backfires but less of a pop.



LMAO

Do not leave it in park and rev.

Problem solved!

[CttH]

Tell your buddy to quit hitting things with a hammer.

Sent from my BE2025 using Tapatalk

[justletmein]

Ok I didn't like how the plugs looked so replaced them all, gapped and added dielectric grease. The backfire is considerably better and less frequent but it started to kick in more again after it warmed up. I did find another or a new exhaust leak right in front of the Cat. I'm told this Cat was clogged or crumbling and they punched it out and "might have crud in the muffler" also. Yeeyee

Maybe a better sound of the backfire here, you can skip to the end. When it backfires it shoots a burst of exhaust out of the back pipes.

https://youtu.be/eVBDOfoOfTs

[Kingfisher789]

I’ll give you some clues....if it’s a dodge w a distributor check replace the cap and rotor. If your Dodge has been sucking air past a manifold leak did a long time it’s got s burnt valve....it probably won’t spit back on the road. Un hook plug wire from bad cylinder and drive that POS rusty dodge south.

[Kingfisher789]

That’s not really a “back fire...

[justletmein]

It's definitely got a leaky intake, looks like it's duct taped on I'm afraid to touch it lol.
Really tough to get back to where the plug wires go, doesn't look like the old distributor caps but I dunno for sure. This is a 1996 5.9L.