Kubota L6060 Engine failure

[MHarryE]

First, the warranty on your fuel system is 5 years or 3,000 hours.

The rail relief valve protects the components from over pressurization. It rarelet, if ever, opens. I dompnt have a L6060 WSM but a larger tractor I has says opens at 31,000 psi, closes at 7,300 psi. I believe your pump has a suction control valve that controls the rail pressure but I’m not sure if the pump is similar, only smaller sized, than the pump on the V3800 engine.

On my engines, the relief is around 30,000 psi but I usually see pressures in the 7,000 - 8,000 psi range at high power. There is a broad range from rail operating pressure to relief pressure.

My guess is electrical but it’s only from tier CRI experience with a different brand.

In my experience I have had engine no start for 2 reasons I can remember. One, engine too cold, couldn’t crank fast enough. Computer had minimum cranking speed before injecting fuel. However, at -20F the engine of my L6060 turns over pretty slow but it will start. Second is worn injectors. I had customers replace our OEM filters with will fit substitutes that didn’t filter fine enough, injectors wore and engines wouldn’t start. But one again, different brand. Throwing out ideas.

 

[Cahaba Valley Farm]

First, the warranty on your fuel system is 5 years or 3,000 hours.

The rail relief valve protects the components from over pressurization. It rarelet, if ever, opens. I dompnt have a L6060 WSM but a larger tractor I has says opens at 31,000 psi, closes at 7,300 psi. I believe your pump has a suction control valve that controls the rail pressure but I’m not sure if the pump is similar, only smaller sized, than the pump on the V3800 engine.

On my engines, the relief is around 30,000 psi but I usually see pressures in the 7,000 - 8,000 psi range at high power. There is a broad range from rail operating pressure to relief pressure.

My guess is electrical but it’s only from tier CRI experience with a different brand.

In my experience I have had engine no start for 2 reasons I can remember. One, engine too cold, couldn’t crank fast enough. Computer had minimum cranking speed before injecting fuel. However, at -20F the engine of my L6060 turns over pretty slow but it will start. Second is worn injectors. I had customers replace our OEM filters with will fit substitutes that didn’t filter fine enough, injectors wore and engines wouldn’t start. But one again, different brand. Throwing out ideas.

Hey Harry, do you happen to know what the exact engine model is for the L6060? I can't find it in the Kubota literature.

 

[goeduck]

This site usually lists the engine model, not this time for some reason.

TractorData.com Kubota L66 tractor engine information

 

[AKForest]

Thanks MHarryE. Lots of information. The electrical schematic on this model tractor indicates that the pressure in the rail is controlled by a sensor at the end of the rail. I tested the Solenoid on the pump. It met specifications. Fuel was being delivered to the input side of the pump. But, with the engine cranking, there was nothing coming out of the output. No fuel was getting to the injectors. Also, the voltage getting to the injectors was insufficient to open the injectors.

 

[Cahaba Valley Farm]

Thanks MHarryE. Lots of information. The electrical schematic on this model tractor indicates that the pressure in the rail is controlled by a sensor at the end of the rail. I tested the Solenoid on the pump. It met specifications. Fuel was being delivered to the input side of the pump. But, with the engine cranking, there was nothing coming out of the output. No fuel was getting to the injectors. Also, the voltage getting to the injectors was insufficient to open the injectors.

You got me scratching my head here a little bit. You started this thread off by telling all of us that you are in for a $10,000 repair. Now you are talking about electrical schematics and testing various parts within the fuel system to determine if they are getting enough fuel and electrical voltage, all of which would require quite a bit of tooling and skill to do such a thing. So where are you going with all this?

 

[Like Tractors]

Thanks MHarryE. Lots of information. The electrical schematic on this model tractor indicates that the pressure in the rail is controlled by a sensor at the end of the rail. I tested the Solenoid on the pump. It met specifications. Fuel was being delivered to the input side of the pump. But, with the engine cranking, there was nothing coming out of the output. No fuel was getting to the injectors. Also, the voltage getting to the injectors was insufficient to open the injectors.

The pressure in the fuel rail is measured by the fuel pressure sensor in the rail, controlled by the suction control valve on the high pressure pump. The suction control valve is a normally open solenoid valve that inlet meters fuel to the pumping chamber. Here is a very easy test, disconnect the suction control valve electrical connector and the output fuel line, verify fuel flow to the high pressure pump, crank the engine, fuel should flow out of the high pressure pump outlet fitting. If not either the suction control valve is not letting fuel pass thru or the pump can not pump fuel. If it passes that test then reconnect the fuel line and retest observing fuel rail pressure, if it doesn't go about 1600 PSI, start measuring fuel return flows to determine where the fuel is going. If the fuel return flow amounts from the rail pressure relief valve and injector return are low, the pump isn't making high enough pressure. If the flow numbers are high, find the leak. Fuel return flow amounts from the injectors combined with the rail pressure relief valve should be below 20 Milliliters/minute at cranking speed, well below that. There, the mechanical test of that system is pretty well done now.

 

[Username Taken]

Hey Harry, do you happen to know what the exact engine model is for the L6060? I can't find it in the Kubota literature.

214 Kubota Grand L6 Cab Review | Tractor News

 

[Cahaba Valley Farm]

214 Kubota Grand L66 Cab Review | Tractor News

Thanks for sending a link to the article Username. It doesn't list the model number of the engine but it is still a very interesting read.

 

[Username Taken]

Thanks for sending a link to the article Username. It doesn't list the model number of the engine but it is still a very interesting read.

Playing junior detective here.....


Kubota engines - Wikipedia

V2403-CR-TIE4B
V = four cylinder inline, liquid-cooled diesel
24 = 2,400 cc (rounded)
03 = 03 Series
CR = common-rail direct injection
T = turbocharged
I = intercooled
E4B = Tier 4 because V2403-CR-TIE4B generates less than 56 kW of power.

 

[AKForest]

In reply to Cahaba Valley Farm, I don't know where you are scratching your head about. Before hauling my tractor 260 miles through the Alaska Range, with the highest mountain in North America, in winter, I tried to diagnose the problem myself. I suspect that most of you would do the same. When I initially contacted the dealership about my problem, they suggested that I check a few things before hauling it in to their shop. I know how to use a multi-meter and an allen wrench which was all the tools it took to perform the tests that they suggested. At that point the dealership said bring it in. The dealership performed more extensive testing on the tractor, replaced some parts, performed some labor and thus the expense.