Idle noise

[JEGraham]

Love the site, and I have learned a ton in a short time here!!!! I do have a question, what I have is '03 305 hp cummins. It's making a noise at idle, that to me sounds like a rod, but at about 1,200 rpms it goes away and sounds normal. To me the engine operates normaly otherwise, the oil pressure, the engine coolant temp, and volt meter all seem to be where the are suppose to be. The truck doesn't start hard, nor does it feel like it has lost any power. Just curious as to what you all may think this noise may be. I've been told by some people that it may be an injector, or the pump. I've also been told that it may be a lifter or valves needing adjustment. Any information is greatly appreciated.

 

[rbattelle]

Things like this are usually very difficult to diagnose over the internet.

What the problem might be depends on how loud the knock is. The 2003-2004 engines were (in)famous for a knock at idle. See this thread.

If the truck is operating normally and isn't knocking under load, I would tend to think it's not an injector problem. Seems like injector problems usually show up as a knock under load.

Is it a 6-speed truck? If so, the clutch on a lot of trucks knocked at idle. Harmless, but many people hated it. There was a TSB that replaced the pressure plate. Here's the TSB.

Ryan

 

[steved]

Is it a 6-speed truck? If so, the clutch on a lot of trucks knocked at idle. Harmless, but many people hated it. There was a TSB that replaced the pressure plate. Here's the TSB.

Ryan

This TSB covers a noise that sounds like someone rattling a couple marbles around a 3# coffee can... not really a knock.

It also was typically present at purchase, not something that developed.

 

[JEGraham]

Thanks for the information. The truck is an automatic trans, I've owned the truck for a couple of monthes now, and before this one I had a '99. I understand the difficulty on diagnosis, like trying to diagnos over the phone. Just was unsure where to start looking. Thanks again.

 

[VanOverbeke]

I seem to have the same problem. I have never been with the windows down much when I lived in Alaska, but now living in New Mexico I have them down. I think it is louder than before, but maybe I am just being picky. I adjusted the valves tonight and the tick seems to be there still. I am thinking about putting a scanner on it to see what the tells. If it shows nothing I will just run it I guess.



Bryce

 

[steved]

I seem to have the same problem. I have never been with the windows down much when I lived in Alaska, but now living in New Mexico I have them down. I think it is louder than before, but maybe I am just being picky. I adjusted the valves tonight and the tick seems to be there still. I am thinking about putting a scanner on it to see what the tells. If it shows nothing I will just run it I guess.



Bryce

Sounds like injector ticking to me... mine did the same thing for several thousand miles before one failed.

 

[MrBee]

One great tool to help to diagnose any ticl is to use a mechanics Stethoscope

and listen for the tick. They have always done real well for me.

 

[VanOverbeke]

I will try to acquire a mechanics stethoscope.



I am holding out for injector trouble so I can justify in my mind some DD 50's. It will be downhill from there. I see a some transmission upgrades, maybe a turbo, and.....



Bryce

 

[VanOverbeke]

I took the truck to the dealer to have the diagnostics done to make sure it was an injector. They called said it was injector number 3 that was bad. Said they had put in a new injector and it was all covered under warranty. I did not return the truck to stock because I was not concerned if they paid. I was figuring I would pay with the mods I have. Guess not. Truck runs without the ticking noise now.