Tune up, than banging sound?

[Dano500]

So, has not been driven hardly at all since I bought it. I finally did enough to get it on the road, in regard to minor stuff like steering box, suspension stuff.

So, I went and got it inspected and noticed that it just feels so sluggish with acceleration, of course maybe that’s what 175hp feels like, IDK. Drove fine, but always had a blown muffler, so I’d hear a popping sound from time to time coming from the back. I replaced the rotor, cap, coil, plugs and wires. Immediately noticed it idles much higher, but now there is this weird “banging sound.”
After tune up, I turned it on, noticed higher idle, but that’s it. Got it, put it in reverse and as I backed up, noticed the sound. Wasn’t with any cadence like lifter tap. I thought something was touching driveshaft, or fan? Maybe I left something somehow. Nope. Couldn’t find anything.

When I turned it on a few days later to explore it some more, I heard it in park. I did noticed an exhaust manifold leak on driver side this time around. It’s not a tic like with lifters. When I heard it from the cab, it literally sounded like something clashing with moving metal. Idk I haven’t don’t any other work on engine besides tune up.


Any ideas? Thanks in advance
Dan

 

[sidschev]

did you cross spark plug wires ???? id check them thats what it sounds like

 

[squaredeal91]

Assuning auto. Check torque converter bolts. I had em come lose and it Sounds like the world is ending loud lol (6.2). I've also had a cracked flexplate that churped and made clanging Sounds. Check that too.

 

[squaredeal91]

And maybe it's idling too high now because it's running better. Idle was compensating for poor running check firing order
18436572.

 

[Dano500]

@sidschev @squaredeal91, thanks, I’ll check firing order. I drove it around the neighborhood just before the tune up and no banging, so maybe firing order vs. tq converter bolts.

Thank you both.
Dan

 

[Dano500]

@squaredeal91 @sidschev - so I checked firing order and it was in order. Could a manifold leak at the block sound like that?

 

[squaredeal91]

It Can. I bought a square once with a header leak and it almost sounded like a knock or wrist pin lol.

 

[Bessie]

So, has not been driven hardly at all since I bought it. I finally did enough to get it on the road, in regard to minor stuff like steering box, suspension stuff.

So, I went and got it inspected and noticed that it just feels so sluggish with acceleration, of course maybe that’s what 175hp feels like, IDK. Drove fine, but always had a blown muffler, so I’d hear a popping sound from time to time coming from the back. I replaced the rotor, cap, coil, plugs and wires. Immediately noticed it idles much higher, but now there is this weird “banging sound.”
After tune up, I turned it on, noticed higher idle, but that’s it. Got it, put it in reverse and as I backed up, noticed the sound. Wasn’t with any cadence like lifter tap. I thought something was touching driveshaft, or fan? Maybe I left something somehow. Nope. Couldn’t find anything.

When I turned it on a few days later to explore it some more, I heard it in park. I did noticed an exhaust manifold leak on driver side this time around. It’s not a tic like with lifters. When I heard it from the cab, it literally sounded like something clashing with moving metal. Idk I haven’t don’t any other work on engine besides tune up.


Any ideas? Thanks in advance
Dan

Could be an exhaust manifold leak. They will surprise you.

 

[SirRobyn0]

Can you record the sound like maybe a short video and post it up?

I feel it's like taking a stab in the dark without being able to hear it.

 

[justhorns]

Use a big a$$ screwdriver to reach around and touch things (that are not moving) with your ear on the other end. This may help find the source. I repeat, do not go near the fan or belts.

 

[Dano500]

It Can. I bought a square once with a header leak and it almost sounded like a knock or wrist pin lol.

So, before I turned it off pretty quick because I was worried it was internal. Now I left it on for a while trying to figure this out, which I think it is the leak, but the truck started almost suddenly dying and I think it is backfiring slightly into carb.

Could be an exhaust manifold leak. They will surprise you.

I just responded up above. I’d appreciate your input.

Can you record the sound like maybe a short video and post it up?

I feel it's like taking a stab in the dark without being able to hear it.

I guess I can try to post it on YouTube and then link here. I wouldn’t know how else to do it. I posted a response to squarebody quote. I’d appreciate your thoughts.

 

[SirRobyn0]

I guess I can try to post it on YouTube and then link here. I wouldn’t know how else to do it. I posted a response to squarebody quote. I’d appreciate your thoughts.

Ya that's the best / easiest way to do it.

 

[GTX63]

Yes, without video/audio, everyone is just throwing darts.
Things like rotten mufflers and leaky pipes complicate things. It's like a doctor checking your heartbeat while the baby is crying. Replace what makes more noise than is supposed to.
Square one, start the motor with the hood open and start moving around the truck until you locate where the noise is strongest.
In park eliminates the rear end, ujoints.
A bad valve can reveal itself with a repeated and lightly audible psst psst psst thru the carb. That and a misfire. There are ways to treat that if that is the problem, or one of the problems.
A long piece of metal ie brake line, can be used like a stethoscope to isolate internal noise.
You might be able to download video from your phone to your computer and upload here using the attach file tab.

 

[sidschev]

rubber hose to find sounds works great

 

[SirRobyn0]

Yes, without video/audio, everyone is just throwing darts.
Things like rotten mufflers and leaky pipes complicate things. It's like a doctor checking your heartbeat while the baby is crying. Replace what makes more noise than is supposed to.

That's a really good analogy. It's like the dude that comes into the shop complaining that he's seeing drops of oil on the ground and the engine is caked with years of long term buildup, but he just wants to replace that one gasket....

Guys have suggested the screw driver or rubber hose method to find the noise which might work, but again is like you doctor trying to listen to your heart beat while the baby is crying. BTY the screw driver method is banned at the shop I manage. I don't like to tell the guys how to work but I feel it's unsafe one wrong move, or accidental move near the fan and that screw drive can go flying, either at you or the truck. The rubber hose can still hurt you, but it's not like it's going to go though your chest if it gets thrown at you.