Engine chatter

[motmot]

Hello I was hoping that someone could help me out. I've recently discovered at 1800 RPM a distinctive engine chatter. Below and above the RPM range of 1800 to 2000 RPM the engine runs smooth however once it gets to 1800 RPM, it hesitates and if you accelerate through it after 2000 RPM it returns to a smooth operation. The only other symptom the truck has is an intermittent lifter ticking noise at idle. Can anybody help me out?

 

[SignalNco]

Where does the noise sound like it's coming from, engine, exhaust, etc??

 

[motmot]

The ticking at idle sound is heard through the exhaust. The chatter is clearly from the engine. I cannot tell precisely where, I'd also like to add that I can see a bit of smoke at the same time as the chatter.

 

[Wildchild467]

Well if your valves are ticking, have you adjusted them? If you know you have an issue with one thing, its best to solve them. Its weird how one thing can effect another sometimes.

If the air compressor belt is loose and it is building air, that can sound like a ticking, or knocking. If the belt is tight and it is building air, sometimes that can sound like a ticking in the air lines which is normal. Dont forget about your other belts too. Again, dont overlook something because it is weird how you may not think that something would be a problem when it really is. I hope this helps.

 

[SignalNco]

Chatter is kind of a broad term. That's one of those things that you wish you could hear for yourself. Do like Wildchild said and check the basics first. Do some searching around on here to find something similar. Sometimes injectors will make a knocking sound as well and to the untrained ear could be mistaken for a valve tapping. Use an engine stethoscope or a nice long screwdriver with the handle against your ear to help pin-point where the noise is coming from. Multi-fuels make lots of noises.

 

[Seth_O]

I had a buddy with an older 2-cylinder motorcycle. He had a persistent 'chatter' or rattle at a set RPM range. It only came with a very specific RPM range, and it showed up every time he hit that range. He spent HOURS hunting it down, ultimately it was found to be the exhaust shield, which had a loose bolt. As the engine went through its range of RPM's it hit different harmonics at different RPM's; at that particular RPM range the engine vibration resonated with the exhaust shield and caused it to rattle.

Obviously a very different engine, but the point is that I would check all the stuff Wildchild intimates, and also look around for stuff that bolts to the engine (could transfer vibrations) and make sure its all snug and greased where appropriate.

 

[DavidWymore]

I'd try valves first. It's easy.

 

[SignalNco]

Just curious, is it leaking fuel anywhere? You also just for good measure might want to check everything on the intake side going up to the turbo (I'm assuming you have one). Make sure there are no obstructions.

 

[Tracer]

I agree. I had a a tapping noise in my truck at idle that drove me nuts for weeks. I checked everything under the hood, and finally found that the copper line going from the air compressor to the governor was rattling against the firewall at idle. I secured it with a clamp and no more rattle. So don't overlook the simple stuff.

I had a buddy with an older 2-cylinder motorcycle. He had a persistent 'chatter' or rattle at a set RPM range. It only came with a very specific RPM range, and it showed up every time he hit that range. He spent HOURS hunting it down, ultimately it was found to be the exhaust shield, which had a loose bolt. As the engine went through its range of RPM's it hit different harmonics at different RPM's; at that particular RPM range the engine vibration resonated with the exhaust shield and caused it to rattle.

Obviously a very different engine, but the point is that I would check all the stuff Wildchild intimates, and also look around for stuff that bolts to the engine (could transfer vibrations) and make sure its all snug and greased where appropriate.

 

[scboolitcaster]

Following this.

I've noticed an intermittent roughness around 1500 - 1800 rpm. I have to fix my brakes before I can check but I hope fixing my fuel leak is going to resolve it.




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[SignalNco]

Where are you leaking fuel? Does it leak all the time or do you notice it more after you drive it?

 

[Wildchild467]

I have a rattle under my dash and am not sure what that is. It sounds like a bracket of some sort. Once you work on these trucks enough, you can almost pin point the sounds, at least I can usually. Each noise has a different pitch. a rattling copper line at idle has a different sound than a loose rattly bolt on the firewall, or some metal making a squeaking sound against something rubber. It is interesting how they all make different sounds. If you are short on time, spray some soapy water on the belts, if the sound goes away, then you know it is a belt issue.

 

[TsgtB]

I had a rattle on a generator from a heat shield, it was much easier to fix than pulling the valve covers....
Also a pinhole exhaust leak at various RPM can be an annoying or deceptive sound.
I've seen a tiny rock that was stuck in a fender support that made a horrible noise...
it could be a number of things, start with the simple things and feel around.

 

[scboolitcaster]

Where are you leaking fuel? Does it leak all the time or do you notice it more after you drive it?

It was leaking any time the engine was running, more after running it a while. Got to where just having the in tank pump on would make it leak. Look for my thread "fuel leak woes".

I don't want to derail this guy's thread.

 

[SignalNco]

Hey there "motmot", any updates on your engine chatter problem?

 

[scboolitcaster]

Following this.

I've noticed an intermittent roughness around 1500 - 1800 rpm. I have to fix my brakes before I can check but I hope fixing my fuel leak is going to resolve it.




Sent from my LG-V410 using Tapatalk

Fixing the fuel leak seems to have resolved the hesitation/miss I was seeing.

 

[TsgtB]

I had a weird clatter today for just a second, I was about to turn up a steep section of road.

I "blipped" (bumped) the throttle (with the clutch in) just before letting the clutch out, and instead of any exhaust reply, it sounded like a momentary tire to louver, or like the rapid clicking you would get when starting a chevy with a dead battery... (not even a couple of seconds) but didnt stall or hesitate, it was still running like normal.

I went ahead for a 30 minute drive, backroads and a few nice highway miles each way. Never a single hicup.
Has anyone else ever experience something like this..?