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Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 8346
Experience:  I am ASE Master Truck Certified.
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I have a 2003 International 8600 tandem axle with a Cat C12

Customer Question

I have a 2003 International 8600 tandem axle with a Cat C12 that has a lack of power.VIN is : 3J062210
Engine Serial Number is: 02KS95555I have had the truck for 15,000 miles. It starts fine and runs ok - it doesn't feel like it has a miss and does not smoke. There is a lack of power though which seems to be getting worse. When I have an empty trailer (about 15k) and try to climb even a small incline I will sometimes drop below 50mph before reaching the top of the hill. Loaded (about 40k) it is hard to get the truck to go above 60mph on a flat road.I have a few questions:
What are the most common problems to cause lack of power in this model?
Can you send diagrams (test port location), instructions (is there a certain rpm to run) and tools (what type of guage) to do the fuel pressure test? (I am mechanically inclined and work regularly with passenger vehicles)
How can I check the condition of the turbo? Is there a way to check pressure and what should it be?
Is there a way to test injectors?
Submitted: 1 month ago.
Category: Medium and Heavy Trucks
Expert:  Cat Man replied 1 month ago.
Thanks for asking your question. I will try and help you out.
Does the yellow check engine light come on while driving?
Customer: replied 1 month ago.
It does not.
Expert:  Cat Man replied 1 month ago.
Thanks for the information.Since the check engine light does not come on, I would suspect 1 of 2 things are causing your problem.The first is low fuel pressure. If there is a low fuel pressure problem, the check engine light will not come on and the engine will have low power. Your engine should maintain a fuel pressure between 75 and 90 psi. There is a plug beside of the secondary fuel filter that is used to check the pressure. If it is low, I would first try the fuel filters if you haven’t already. If it is still low, you may have a failed fuel pressure regulator, which is located underneath the bottom of the filter housing. I have replaced a ton of these for low fuel pressure. It is kinda a known problem. You could also have a weak fuel transfer pump or restricted hand primer pump, if your engine has one.Second I would suspect you have a low boost condition. This can be caused by a leak in the air piping or air to air aftercooler on the truck. I would first inspect all of the piping to see if there is a hole in any of the rubber boots that hold the pipes. From there you may want to cap off one side of the air to air cooler, and pressurize it. They have been known to crack and leak and cause low boost.Please let me know if you need more help or have more questions.
Customer: replied 1 month ago.
Would you send a diagram for the fuel plug location? What type of tester should be used (is there a special one for semis or will a regular vehicle fuel pressure tester work)?
Expert:  Cat Man replied 1 month ago.
Any psi gauge will work. There should be a single plug on the secondary fuel filter housing.
Customer: replied 1 month ago.
Is there a certain rpm it should run at or just at idle? Do you have a diagram showing the location?
Expert:  Cat Man replied 1 month ago.
Idle can be programmed from 600 to 750.
Sorry. I do not have a diagram. But if you find the secondary filter on the non turbo side of the engine. The plug is on the filter housing.
Customer: replied 1 month ago.
I will check the pressure.
The truck has 550,000 miles. I bought it from a fleet company. How reliable are these engines and typically how long can they run before they require major work or engine overhaul? The reason I am asking is that I have the option of sending this to dealer auction and just buying a different one.
Expert:  Cat Man replied 1 month ago.
Normally these get up to around 750,000 miles before overhaul.
The biggest issue with these are the cam followers. They have been known to fail often on these.
Please reply back if you need more help or have more questions. I am happy to assist.
Customer: replied 1 month ago.
regular pressure gauge I have has screw type and looks like I need a special adapter no one has around here. any other way to check it - such as inline.? If can, please tell me the line location. (I can send a photo so you can mark it as well)
Expert:  Cat Man replied 1 month ago.
you can check it in line. Use the line that runs from the filter housing to the manifold.
Customer: replied 1 month ago.
I cannot find which is going to the manifold. I have attached a photo. I am thinking C is the test port. Line A is the line coming from the rear (tank area). Line B looks to be going down towards the block.
Expert:  Cat Man replied 1 month ago.
C is the test port. Line B comes from the fuel pump. A is the fuel return line. The only way to test pressure is C.
Customer: replied 1 month ago.
Unfortunately there are 2 things you have mentioned to be incorrect so far. We cannot use a regular fuel gauge (it requires a special adapter) and then you said we could test inline but there is no such line to do that. I have spent quite a bit of time to get tools which will not work.
Expert:  Cat Man replied 1 month ago.
you have the older housing assembly that bolts directly to the fuel manifold. Not the newer one that does not. Sorry. The fitting is the only way to test the fuel pressure.
Customer: replied 1 month ago.
I did send you the engine serial number in the very beginning. it seems like try to make as much as money in front of a computer answering multiple customer questions simultaneously without paying attention to details of the question and not actually trying to solve the problem..
Expert:  Cat Man replied 1 month ago.
Have a great day sir. Not my faulty you do not have the correct tooling. I'm out. Good luck

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