$2945 from Cat. Haven’t checked Kubota. Seeing Denso pumps advertised for Kubota C3.8. Anyone used anything besides OEM?
I’m only surprised that it wasn’t more. My WAG for OEM would have been around $4k.
Any viable options?
Sorry, I have no idea. Companies I worked for would only ever fit OEM parts.
Yep. I am very skeptical of quality of some of the knock offs. Might be same as OEM but I can’t get that info.
It’s not just Cat that use these Kubota engines in machines like yours so there ought to be somewhere selling genuine parts, either Kubota-branded or something like Denso fuel systems (who probably made it originally) that will fit.
What cylinder does hp pump time off of?
A fella I know just did a pump on the C3.3B in a 279D and he told me the pump was significantly cheaper through Kubota. Don't know if that will translate over to the larger C3.8.
Finding brand new Denso pumps but have yet to cross one over to a 299d2. 1/2 the Cat price for one that fits 289d3. New not rebuilt. Expert Diesel out of California. Where would the serial number be on the engine?
What’s the machine Serial Number.? I can find the engine details from that. Otherwise look for a sticker on the valve cover.
Got it. Had to hunt and clean a little bit
Find a Kubota engine dealer, not tractor dealer. PM me if interested
Engine S/N should be 2HQ0199.
If replacing these pumps you will need to mark the gear BEFORE removing pump. There are timing marks but only useful if timing marks are aligned all the way to the crankshaft. If you do not mark the gear, th only way to time is to remove the timing cover and reset the entire gear train. Off time does NOT work. likely will not run at all, or run poor by chance.
Check for a broken spring under neath the 4 bolt top part of pump. What exactly are the symptoms you are having?
Cat Et calling for 4400 psi to start. It is cranking at 2200 psi
What other causes would there be for low cranking fuel pressure? Is there high pressure relief valve?
Bad injector leaking fuel thru, rail relief valve leaking. Fuel supply issue. 1 Should have positive low pressure fuel 10 psi at pump IIRC 2 Rail relief simply remove hose, should have NO fuel normally. 3 Injectors. Use rail cap off fittings to eliminate 4 Check for broken pump spring as in post #16
Excellent. I have pressure on inlet side. Filters clean. I will try to find caps.
Aren’t the lines for the fuel injectors on these engines single-use only.?
According to the book maybe. We have had hundreds of these lines off, not only Kubota but various small diesel. Maybe 2 that we had to replace a line due to leaking. And one of those not related to disassembly that I know. Be interesting to know others experiences. I feel it is a possible failure, so book says change em. In real life, rarely needed.
Good to know. The idea of the question was more directed at the OP to have him take care when removing & installing the lines for testing.
Much appreciated. I had watched a video on the Tube where a guy was t-shooting a Doosan 4 cylinder and was discussing the reuse of the line from rail to injector. Makes sense with the pressure they are seeing.
I am trying to post a video of the fuel rail bypass while cranking the machine. It will not let me. Any suggestions or is that something you can’t do? I am getting 2-3 ounces of fuel during a 5 second cranking period.
You can’t upload videos direct. They have to be hosted elsewhere and linked.
Should I be getting that much fuel through the bypass?
Which pump? Was assuming you meant the high pressure hydraulic pump.
High pressure fuel pump
Good news is your pump is probably working. . . This is your problem, your losing fuel pressure somewhere. Is the bypass return isolated? The injector and HPCR return both tees into that fitting.
I might have been premature in posting. Looks like it is coming off a tee. Very difficult to see back in there. Camera showed it better. HPCR?? The pump was showing 2200 psi cranking on CAT ET If I remember correctly it wanted 5000 psi
That tee has a banjo bolt that carries the fuel from the relief valve. The pipe comes from the injector return, and also picks up the HPCR return via a hose tee'd into the bottom of that pipe. Try to separate the three and isolate the high return flow. The banjo bolt can be removed and the pipe pushed far enough aside to separate those two. The pump return is a hose so can be easily removed.
HPCR?
Rubber hose that tees in goes back to fuel pump. The steel tube runs all the way to front of engine and has a banjo fitting I circled on pic. So that is the injector return ?
Yes, steel tube is injector return, rubber hose HPCR (high pressure common rail) pump return. If you can split out these 3 and crank to see which one has the fuel flow.
What is this banjo fitting sitting on ? If I take it off and disconnect the rubber hose from the fuel pump and plug that that should get me through isolated?
Banjo fitting brings fuel from relief valve to the pipe. I would simply remove the banjo bolt, move the pipe aside a little and remove the rubber line from pump. Then have someone crank while you watch to see which of the three ( hose from pump, pipe from injectors, or banjo bolt hole from relief) that has flow.
Yes sir. I can do that. Is the relief valve for the rail?
Is there a resource out there that can bench test an injector pump?
Lets find the high return flow first, I suspect that is your problem. Yes, a diesel shop specializing in common rail should be able to bench test. However, those are few and far between. Forum guys, I would like to hear your thoughts on common rail testing, and vendors that you use.
All we would do is fit a Reman pump if the installed pump wasn’t performing after eliminating all other possibilities. It’s not as though internal repair parts are available so testing is kind of wasted because whatever is wrong with it nobody can fix it anyway.
It would be nice as a novice troubleshooter to have pump dyno’d before dropping the coin on a new one but I understand what you are saying Nige. I just got back on the machine today. Had to get a motor block repaired for a customer. I went about isolating the return from injectors, rail relief valve and pump a little different. I could not get the banjo fitting at the tee removed. I couldn’t see it and knew it would have a seal on the bottom and didn’t want to lose that. I disconnected the rubber hose off the pump at the steel tube. I removed two coolant hoses and water pump pulley to get at the banjo fitting on the front of the engine. I now have rail relief, fuel pump hose and injector return isolated. Should be able to crank it with belts off water pump to see where flow is coming from. I plugged the outlet where the fuel return goes to tank so anything coming out of rail relief valve should show up at the tee where fuel pump return is disconnected. Thunderstorm ran me off so tomorrow should tell the story.
Got some help to crank machine while I watched injector return, rail relief and fuel pump return. All of the flow was coming out of the rubber hose that runs from fuel pump to injector return line.
So we're back to the pump. . . Good to know I guess. All I can add is that clean fuel is essential for these systems.
Yes sir. It had some nasty stuff in the tank when I got it 100 hours ago. I flushed the tank the best I could. Changed separator filter twice. Changed screen ahead of lift pump twice. It still shows gunk in them. I hope injectors aren’t shot.
To put it in perspective this type of machine suffers a lot from poor-quality refuelling. They get filled from jerrycans or whatever "suitable" container is available instead of being filled from a transfer tank with filters in the line before the fuel comes out of the gun. What came out of the bottom of the tank has obviously passed through the filters and by now will have reached the pump. If you get away with anything less than a new HP pump, a fuel rail, and a set of injectors consider yourself lucky.
Ouch.
You will struggle to get your pump “bench tested” as it may contaminate there bench tester. Ive found that they will pull it apart and inspect for damage, quote repair, repair then test. OEM price is often similar by the time you factor in labour and freight.
One thing I have not tried is to try starting it in starter fluid. If it fired off and achieved higher than the 5000psi that is called for to start would it run? I really need to get it off my front sidewalk and 150’ out to my pole barn.
That can work with injectors that have high return flow. We prefer to cap off one injector and run on 3 cylinders to unload or move into the shop. Do not know if will also work on weak pump. One consideration is that if pump is failing any debris will go straight to injectors. . .
Seems like there is no tried and true way out of this. Sux.
Have anything around with forks that can lift it?
I don’t. It’s kind of the center piece of my farm equipment.
I have nothing to add on getting it running, but I can maybe help with getting it moved. Get one end jacked up with bottle jacks, and get some 3" steel pipe. Start working pipes under it, and you should be able to pull it to your shop, provided you don't have any big ditches to cross.
Quick question. What is the purpose of the regulator circled in yellow on the attached pic?
To regulate the pressure in the HP pump inlet line. If the pressure increases over the set value the excess is bled off into the return line to the tank.
Ok. From the tank to cartridge filter, to lift pump, to filter separator, to the tee(relief valve), then to hp pump. I have checked pressures and flow along that route. I see the regulator outlet goes to top of fuel tank on starboard side. Where is it fed from? I am missing that looking at schematic.
The filter head. It's screwed right into it.......... It's called a regulator. It's actually a check valve.
So it goes through the tank from bulkhead to bulkhead? Then to the regulator?
The attachment in Post #58 describes how it operates. The purpose of the orificed check valve is to remove any entrained air in the "dirty" side of the fuel filter assembly because the air will not easily pass through wet filter media. The title "regulator" is a misnomer, it doesn't actually regulate anything. The outlet from it is teed into the "return to tank" fuel line.
I understand the fuel flow in the pdf. The tricky part was the line coming off the filter head into the bulkhead on the fuel tank through the fuel tank exiting via bulkhead into #1 I circled in the attachment post 55. It just wasn’t intuitive for it to pass through the tank instead of a direct line to the “regulator”.
Just an update. I have the new hp fuel pump and related gaskets sitting here. Waiting on mobile tech to install. I am slowed right now with a wrist injury and can’t do the work necessary to change the pump out not do I have ET to monitor what goes on after pump is changed. However….the machine was still sitting in my front yard at our sidewalk. I thought I would at least try to crank it. Very short crank and it fires right up. No codes. No alerts. I quickly moved it to my barn. Wife was really pleased to have it out of the front door. Let it sit for 2-3 hours and tried to start it again. No go. Head scratcher.
Here is the Denso number on the new pump from Cat. I can’t find a Denso pump online with 509 prefix. The Kubota replacement for the 3800 series 500-50501 looks exactly like the pump from Cat.
Finally got my CAT ET and SIS loaded on my laptop, thanks AristoTruckTech, and have begun changing fuel pump. Is a three jaw puller sufficient to pull the pump gear or do i need to pop for the Cat tool?