Cat C9 engine noise

[Tom and Pat Fudale]

I have developed a strange noise on start up.  After the air heat light goes out, and I start up the engine, it makes a very loud rattling noise, somewhat like a spark knock in a gas engine.  This lasts for a couple of seconds, and smooths out and runs fine. This is the Cat C9 400hp.
Also, on my trips this fall, on a very cold morning, it ran fine for about a mile to the interstate.  When I accelerated to highway speed, I developed a terrible vibration until I got up to speed. I took it to Ring Power in Florida, but they could not get the condition or any engine codes. It does'nt do the vibrating thing on warm start-ups. I can't really tell if its the engine or the transmission.

[Gerald Farris]

Tom,
It is impossible to properly diagnose an engine noise, without being able to hear the noise. However, your description sounds like you have an injector malfunction. The problem that you have is, that you have to be able to reproduce the malfunction, or the Caterpillar technicians will not be able to determine that it is an injector, and if so,, which injector is the problem.

It is much to expensive to replace injectors unless you are sure that you have an injector problem, and which one is defective.

Gerald

[Richard And Babs Ames]

The injectors are over $300 each plus installation. We have lost two but both only under load and warmed up. Both failures set a code for Ring Power to read.

Air in the system comes to mind also as it can cause rough running you might have a very small suction leak at a fuel filter or fitting that would not show up by diesel showing. Does it only happen after sitting at least a few hours and did you change your fuel filters?  

[Tom and Pat Fudale]

This first noise that comes from the engine is a clattering noise that lasts only a few seconds and then stops and runs fine. This happens at every start-up. No air leaks and isn't related to oil change. The other vibrating while accelerating only happened when it was extremely cold. Doesn't happen when engine is hot. No problem after engine is hot and running at highway speed or running up-hill on hard pull.

[Gerald Farris]

Tom,
Like I stated earlier, there is no way to properly diagnose a noise without being able to hear it. There are numerous possible reasons for the noise that you are describing.

You could have a malfunctioning injector that is fuel starving a cylinder on startup. There is also the possibility that you could have something like a piston slap or crankshaft bearing noise that goes away as soon as it receives adequate oil flow. The oil will fill in the space between the two surfaces and act as a cushion to stop the noise.

The bottom line is that you need to get a knowledgeable technician to lessen to the noise, and since it only happens cold, you will have to overnight or leave the coach at a Cat dealer to check out the noise. This may take several days to determine what the noise is, or they may crank-up the coach and know immediately what the noise is. It may be very minor or major, but you have to determine what it is first.

Gerald

[Tom and Pat Fudale]

Cat service manager says that one of the injectors has a very minor leak while engine is not running. He wants it toget worse as it does'nt clatter long enough to be able to isolate the offending injector.

[Wayne Baumann]

HI,

I HAVE A 'O7 CONTESSNA WITH A C9 ENGINE, AND THEY HAD TO REPLACES #5 INJECTOR TWO TIMES IN  150000  MILES.  THE FIRST TIME IT HAD A SLOW LEAK, AND THE SECOND TIME IT STUCK WIDE OPEN GOING DOWN THE HIGHWAY AND IT SHUT THE ENGINE DOWN AND HAD TO BE TOWED 150 MILES TO DENVER COLO.  HOPE THAT THIS INFORMATION CAN HELP YOU,

WAYNE BAUMANN