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Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 8630
Experience:  I am ASE Master Truck Certified.
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We have c15 acert twin turbo. The computer is not showing any

Customer Question

We have c15 acert twin turbo. The computer is not showing any codes. The motor seems to run well with no load or a little load. But, will only build 35# ***** black smokes and low power under load. Have resolved any possible leaks before and after turbo. Also, will die sometimes immediately after startup
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Cat Man replied 1 year ago.
Hi. Thanks for asking your question and requesting me! I will try and help you out.
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. Since you have already inspected the piping and turbos. Next 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. I see this a lot.
Please let me know if you need more help or have more questions.
Expert:  Cat Man replied 1 year ago.
Hey. I just wanted to see how things were going. Please let me know if you need more help. I am happy to assist. If my information was helpful, please leave a good or higher rating so that I receive credit. Thanks.

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