Kubota SVL 90-2 Chugging & Skipping

Hey all! I have had this machine now for three years. Bought it with 300 hrs and now just clicked over a 1000. This machine truly has been babied and maintained very well. It gets used for basic construction work in the summer but plows snow in a couple commercial lots in the winter. During this time it’s been in and out of the dealer shop for a bunch of things some normal some serious. Most of the time it was DPF related issues and finally after 4-5 cleanings was just replaced it within the last 75 hrs. Sensor issues related to oil pressure because something freezes in the dpf/oil system. Temperature problems. All of the, usually throws some kind of code. Now I think the issue at hand is fuel related, but no codes at all. It’s starts just fine and can idle on high with no noticeable change, but as soon as it drives or actuate any hydraulics the engine bogs down and sputters then recovers and repeat. We had issues in the past with the fuel water separator. We drain it and clean it then usually solves the problem. Not this instance though. So got a union and bypassed the filter hoping the elbows were dirty and again no change. We had the tech out and he said there was erratic flow in the fuel system which was due to the flow control valve. Replaced it and it corrected the readings on the fuel rail, but still skips and sputters under load. The fuel pressure readings are all good and reading as they should. We don’t think there’s an issue with gelling because it hasn’t been cold enough. Even still we’ve been adding fuel additive every fill up, and the filter has less than 50 hrs on it. Needless to say we ordered a new one just in case. Should be in tomorrow. The tech says the only thing that can be the problem is the injectors. Now I’m not denying that very well could be the issue, but I take everything the service departments say with grain of salt. I am just continually surprised with the amount of things I have had to replace on a machine with such little hours on it. If you have any light you can shed on this it would be greatly appreciated and if you’ve had similar issues please share. Thanks for your help!

This may sound overly simplistic, but could the fuel itself be contaminated? Maybe drain the existing fuel, change the filters, and put fresh fuel in.

I mention this because one time I accidentally added gasoline to my diesel tractor. It idled fine, but under load/increased rpms it ran rough. Finally realized what I had done.

Have nothing to lose except time....

Start simple and change the fuel filter. I have had nothing but problems when it's cold with that filter, I had it parked in a heated garage, loaded it up to go move snow 5 min down the road, made two passes, sputtering and bogging, trailered back to the garage, changed the filter and it was fine (filter only had 100 hours or so on it), this has happened several times when it's been cold. I buy my fuel from the same spot and put additive in, it's the only machine that has this issue and from talking with the dealer they say that double fuel filter sales in the winter, I think it's because it is a very low micron filter and if the fuel filter has any water trapped in it you're done. A side note, DO NOT LET IT IDLE FOR EXTENDED TIME!! And run it pretty much wide open, that should end any DPF issues.

Thank you guys! Just picked up the new filter and were going to back blow the tank and see if the fuel flow is better then clean the tank. We’ll see what happens. Out of curiosity what do you use for additive?

Just curious if this problem was ever corrected. We are having similar issues with our machine. It will bog down and even die. It will not keep the fuel bowl full either. We have cleaned the tank replaced all fuel lines replaced the fuel pump filters etc. Machine has no codes when it happens only code that sometimes comes up is for intake air temp but is not there often.

By pass fuel water separator with a inline fuel filter temporarily. Those housing suck air and cause those problems. Also is there a orange valve on the fuel filter housing? If so it needs to be closed not open. If it's open you'll loose power under load. The valve was to help bleed the the filter and has been removed on newer machines

Ok I will bypass that filter. The valve your talking about is closed. I will report back when I find out if bypassing the filter works out or not. Thank you for your help

Can you take a picture of the valve. It's not on the fuel water separator it's on top of the fuel filter housing and is orange. If bypassing the clear water separator works take fuel water separator off and make sure the 90 degree fittings aren't clogged that also happens often

The orange valve has to point up

Yes the orange valve is closed. I haven't bypassed the water separator yet but plan on it tomorrow. I did take the filter housing off and check the elbows in both the water separator filter housing and the fuel bowl housing. I'm hoping the water separator housing is sucking air. I pulled the fuel petcock off the fuel bowl and replaced the oring and checked for debris and it was all clear

Ditto midnightmoons comment. We used to change out a fair amount of those housings. And the 90 elbows get clogged easy as he mentioned.