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My d6h cat loses power after 20:minutes. Idle it for a few…

My d6h cat loses...

My d6h cat loses power after 20:minutes. Idle it for a few minutes and it will power back up for a much shorter time. I have replaced the air filters, and both fuel filters. Today I took the line loose between the primary filter and the check valve. Flow was good to the check valve but very weak coming out of the check valve.

Mechanic's Assistant: What is the complete model and serial number of your machine?

3zf04444 Cat d6h 1992 model

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Answered in 2 minutes by:
7/28/2020
Mechanic: catmastertech, Technician replied 2 years ago
catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 4,039
Experience: Field service technician for CAT 19 years.
Verified

Hello,

Which check valve are you describing? Where is it located?

Have you checked the fuel pressure at the injection pump?

Please note that I am not set up for phone calls. Please ignore the site pop-ups, they are site generated and I do not have any control over them.

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Customer reply replied 2 years ago
Check valve is between the primary filter and the secondary filter.I have not checked the pressure.Looks like three bolts to take the check valve apart. Just wondering if it is tricky to get back together.
Mechanic: catmastertech, Technician replied 2 years ago

Are you describing the one in the outlet of the primary filter (strainer)?

It sounds like you are describing the fuel transfer pump.

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Customer reply replied 2 years ago
that is probably right. I took the line loose and could see that the next part was a check valve.
Mechanic: catmastertech, Technician replied 2 years ago

Let me detail the thing I have seen.

The most common issue for lost power is plugged filters. Assuming you have already addressed that, next would be blocked lines. If you let the fuel flow when the strainer is off, it should flow freely from the tank. You can then remove the line from the strainer and it will be slower but still flow freely to the transfer pump. Once you have a good supply of fuel to the transfer pump, the next thing is to know if the pump is making pressure. It must make 32 psi under load or the engine will be weak. If you don't have a gauge, then replace the transfer pump with a REMAN transfer pump from your CAT dealer. Part #0R-3537.

If you complete all this work and the problem keeps returning, your tank may have trash in it and needs to be removed for complete cleaning.

If it still looses power, get a gauge and hose assembly and watch the fuel pressure. If the pressure remains above 32 psi and the engine is still weak, check for other causes first, and then you may need to look at injectors or the injection pump repairs.

catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 4,039
Experience: Field service technician for CAT 19 years.
Verified
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Customer reply replied 2 years ago
Any chance that there is trash in the transfer pump? The machine has full power up to the point that it shuts down. It is pretty abrupt, but does not completely die. Left to idle it will eventually return to full rpms, but loses power Quickly.
Mechanic: catmastertech, Technician replied 2 years ago

Normally, trash in the pump will be a constant loss of power. It sounds more likely you have trash in the tank and it is getting suck over the supply fitting of the tank. When it stops the debris floats away since the engine is not running and pulling it over the fitting.

This can be a very frustrating problem but, I have seen it many times before. I would go directly to the tank first.

If you are finding trash or sludge or algae in the fittings or other check valve or hand priming pump's check valves, then you could also have trash in the injection pump housing and it could be blocking the return check fitting causing too much fuel pressure.

catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 4,039
Experience: Field service technician for CAT 19 years.
Verified
catmastertech and 87 other Construction and Road Equipment Specialists are ready to help you
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