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Cat Man
Cat Man, Caterpillar Engine Expert
Category: Heavy Equipment
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Experience:  23 Years Caterpillar Engine experience.
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Caterpillar Caterpillar engine problems

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Caterpillar engine problems
Hi. Thanks for using JA! I will try and help you out.

When you say the injector is not seeing enough fuel, are you saying the engine has an "Injector not responding" code? Or something else?
Customer: replied 5 years ago.

Hi Cat Man,


The code recorded is 653.7 the book says this code is "injector fuel flow is lower than expected for number 3" This info is coming out of the engine management book that came witht the new computer.


Side note: the new computer is not working properly or not being allowed to work properly because there is a problem with the eingine? This what the PGL people told me that sold me the new computer.


I pulled the valve cover and inspected the line and harness to the injectors, not sure which cylinder is number 3? Did not see any obvious problems.






Thanks John

Hey John,

That code is a not responding code for the injector. On a common rail fuel system this code means the injector needs to be replaced because it has mechanically failed. Basically, when these injectors begin to fail, they pull too many amps. In turn the ECM will set this code.

Also, the number 1 reason for this failure to happen is the injector has overheated due to a failed oil spray. There is a hole in the rocker arm assembly that squirts oil on the injector to cool it. I would remove the valve cover and run the engine and make sure you see oil squirting from the rockers onto the injector. If you do not, the rocker assembly must be replaced along with the injector. If you do see oil, the engine just needs an injector.

Please let me know if you have more questions.
Customer: replied 5 years ago.

Thanks Cat Man,


which is injector 3? do you start from the front of the engine or back, are the one two three in a row or is there a firing order that tells me which is number 3?



To find number 3 you would count from the front. 1,2,3 etc.
Customer: replied 5 years ago.

Hi Cat Man,


Sorry it took me so long to get back toy you, I have not been able to get to the machine to check the advice you gave me, other things taking my attention, should I accept and will I be able to to talk to you some more?




Either way is fine. You can accept now or later. If you accept now, you will be able to talk to me after hitting the accept button. I will be here as long as you need help.
Customer: replied 5 years ago.

I see oil coming out of the rocker, it looks as if the oil is falling short of the injector, also can you tell me proceedure on how to pull this injector, do I need any special tools?


I do not see any screws holding the injector in?


Thanks John

Thanksa for the information.

I can get you the procedure. Could you get me the engine serial number? If it is a 6.6, it should start with 666.
Customer: replied 5 years ago.

Thanks for the information.


Here is the procedure to replace the injector. If you have never replaced an injector in a 6.6, there are a few things you need to know.


First, these fuel systems are common rail. This means that all of the fuel pines that you remove in order to replace an injector must be replaced. They are a one-time use. Please do not break the fuel lines loose after installing them and try to bleed the fuel. It is not necessary and is EXTREMELY DAANGEROUS due to the high-pressure fuel that will come out. And lastly, these are software injectors. This means that there is software that must be installed into the engine ECM after installation of the injector. Make sure to write down the serial number and 4 digit confirmation code. In order to program the software, you will need Cat ET software. << click here

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