Komatsu WA500-3 low fuel pressure

I'm doing this for my husband who is at working trying to fix this Komatsu WA500-3 wheel loader right now. He said that it is giving a low fuel pressure rail code. How do you fix it? Or does anyone have the computer schematics that I can send to him or you does not matter. He works for a mining company and they have had four guys already look at it with no luck as to why or how to fix it. My husband is usually an operator and not a mechanic but no one seems to know how to go about this. We need help!!! Please.

Thank you

A very loving and supportive wife

Serial number is 52133 if that helps I do not know the year. He is trying to figure that out as I type.

Rabbit,

There were two series of SA6d140 Komatsu engines in WA500-3's with serial numbers in the 5---- range. Your machine has the later SA6D140-3 engine which has a common rail fuel injection system on it.
From what I have seen fuel filters, being clogged, are the most likely culprit of low rail pressure. If changing fuel filters does not fix problem may have to have someone check injector fuel return rate(spill), fuel pump spill rate, and common rail limiter spill rate.
Of course there are other items to check as well, ie: fault codes, wiring to high pressure pumps pcv's and so on.

Hope this helps.

codes

coalrulz said:

Rabbit,

If changing fuel filters does not fix problem may have to have someone check injector fuel return rate(spill), fuel pump spill rate, and common rail limiter spill rate.
Of course there are other items to check as well, ie: fault codes, wiring to high pressure pumps pcv's and so on.

Hope this helps.

Click to expand...

It's not the fuel filter or the pump. It also cuts the power to about 1/2 and gives a caution light. What the reasons for the code all and any that you may know of? Where can I get a copy of the codes and the reasons?

That's really coincidental. This machine's serial is 52138.



I would agree with fuel filters being the culprit. Filters are cheap. It could also be an injector that is derating the engine. The only way to tell is with the scan tool. Sadly I know how your husband feels working without the correct diagnostic equipment, might I add, an operator working on newer common rail equipment usually is like somebody wandering through a forest at night.

I have found that a common rail fuel system is a common rail fuel system, be it john deere, cummins , MB, ect. I have no experience with a komatsu engine . The wa 200 I have seen had the qsb cummins I seem to recall though branded komatsu? The low power when light is on is because the engine is in derate. One of these will be the problem . Fuel filters, pusher pump, high pressure pump. Rail relief valve, injector(s) , rail sensor, wiring between rail sensor and ECM, ecm. If the engine cranks and runs fine till the light comes on then derates as long as the the light is on, I would suspect the rail sensor or the wiring to it. I often find the problem in the connector plugs. The rail sensors are generally inexpensive so without scan capabilities I would just go ahead and replace that sensor. I would also wiggle the wires at sensor and ECM while the caution light is on to see if it goes out. Generally pumps , rail relief valves, and injectors will cause other problems such as intermittent no start. The only thing that scan capabilities would help you with is the ability to see live data and observe what the sensor is communicating to the ECM. A volt meter is all you really need for diagnostics since you already know low rail pressure is fault area.

Something tells me that I had the same issue and there's a banjo fitting with a screen in it like the earlier mechanical engines...might be worth a quick check...

Thank you

I passed the information on to my husband and we are both very appreciative. Thank you so much for all your help.

Check all the hoses and connections from the fuel tank to the pump, the banjo fittings can get blocked causing a low pressure fault.

rabbit464 said:

I'm doing this for my husband who is at working trying to fix this Komatsu WA500-3 wheel loader right now. He said that it is giving a low fuel pressure rail code. How do you fix it? Or does anyone have the computer schematics that I can send to him or you does not matter. He works for a mining company and they have had four guys already look at it with no luck as to why or how to fix it. My husband is usually an operator and not a mechanic but no one seems to know how to go about this. We need help!!! Please.

Thank you

A very loving and supportive wife

Serial number is 52133 if that helps I do not know the year. He is trying to figure that out as I type.

Click to expand...

Im having the same issue with my wa500 did you figure out what the problem was with low fuel pressure code?:Banghead

We have a 3-lk machine that just did the same deal, The lift pump or pressure pump for the common rail gets weak. ours would run fine in the morning or early morning but once hot it would power down. We replaced the whole pump, you can just replace some parts, but it is not a whole lot more money to buy a whole new pump.

Same issue over here with a WA500 - 3LK ( serial # A72397 )

Any updates?