Roxor dies under load

[Farmer Ryan]

Hello! I am new to the forum. We have a 2018 roxor and love it. We got ours used with a stage 2 Diesel Freak tune. About 2 months ago it started dying while under high loads at higher RPMS. I changed the fuel filter hoping it would make it work. While it was in the shop, I also took off the fuel tank so I could weld reinforcements on to the back frame because ours had began to crack. While removing the tank I broke the return end off of the fuel pump. We got a new one and replaced it and all was well for about two weeks. We used it on a -5 degree morning and it gelled up after about 5 minutes (It was treated with Howes, I am not a believer in it). on a much nicer day, we limped it home, changed the filter bled the system, and now it is dying under high loads again. I have an OBD2 reader, and there seems to be no connection with fuel rail pressure or rpms that is consistent. Any ideas would be appreciated.

 

[txroadkill]

You got a new return end for the pump or a complete new pump?

 

[Farmer Ryan]

I got a whole new fuel pump unit. It seems like the whole unit has to be replaced if the little plastic quick connect barb breaks. I had a hard time finding one, but Torque King had a few and got it shipped right away. The new one fit and worked, though seems a little slower than the old one possibly? The old one did seem rather yucky but sounded like it spun faster maybe. It did run well after the pump was replaced, but it seems like maybe it is still not getting enough fuel now.

 

[txroadkill]

Could it still be gelled but inside the pump?

 

[Farmer Ryan]

It is possible, but I really don't think so. I have driven it quite a few miles and let it idle for a while and I think all of that fuel is gone. We also used a 911 ish product to help get it going. Is it possible to get just the in-tank cartridge pump? I wouldn't be opposed to trying a new pump but don't really want to get the whole assembly again.

It does take a while to get going when cold, almost like there is air in the line. But it runs fine until it dies, and restarts quickly once it is warm.

 

[MikeT]

the symptoms are what you would expect if the return line for the fuel was not open. Check to see if it got pinched shut during your repairs etc.

 

[Longslyde]

Just trying to clarify, is it happening only when it got cold? And do you have the factory belt driven fan on it? I see you're in Missouri, not sure how much Bio Diesel they run by you, but that can be a problem. In Minnesota, they specifically regulate it to a low content in the winter months due to gelling concerns. Two things possibly causing your problems, not a definite:
1: Factory fan moves a lot of air, which is good, unless you're trying to build heat. Especially if you're on 5.38 gears. And these little engine don't build a ton of heat. So the excessive air can cool the Diesel down to a gelling point if is cold enough, AND you're high in BIO-Diesel content.
2: Too high Bio Diesel Content for the temperature.

Howes and 911 Diesel Treatment don't really help the Bio DIesel as much as they do for Ol' Dino DIesel. If Bio Diesel is your problem, what's happening is, the cold air is gelling the fuel before the pump. I.E in the filter and lines to the high pressure pump. The in-tank pump is strictly a low pressure feed pump. It won't push gelled Bio. If the Bio-Fuel turns to "Bacon Grease", which is what actually happens above 10-15% bio in the real cold, no feed pump will push it through and the pressure pump will starve, and then....chug out and die.

I've been selling HD Semi Trucks for years, believe me, I've seen this in person many more times than I would like. Not saying this is what's happening in your case, but it sure sounds familiar to me with what you're describing.

If there was a way for you to pull that fuel filter AS SOON as it gave you the problem, not allowing it to warm up at all, you might catch the problem. It would be black, sticky looking grease. But the problem is as soon as you leave it sit, without the engine fan blowing around, it'll probably loosen up and look fine. Within minutes actually. Which would explain why you say it starts up fine again.

You could also remove the fan blade as a test, since it's cold, and drive it in the same conditions. It definitely won't overheat if you're moving, but keep an eye just in case. If the fan was the problem, it won't chug out on ya. Then you found the issue. If that ends up being the case, then electric fans would be the remedy.

Sorry for long thread, but this isn't a cut and dry issue. LOL

Hope that helps!

 

[Farmer Ryan]

The problem is the same in higher temperatures, and I have removed the filter right after it dies. I think we also get less bio diesel in our farm tank but am not 100% sure on that. If it is the return line, how do I check that? It should pretty much dump fuel at idle right? I have never done anything with the return side.

 

[Longslyde]

if it does it in higher temps, ther would rule out Bio issues. Does your have another filter in line before the main filter, on the frame rail? That could be plugged up also...

 

[Farmer Ryan]

I don't think so. I was underneath it earlier today and didn't see anything else on the in line. What type would it be? I also felt along the return line and it didn't seem kinked or anything.

 

[Longslyde]

If you had one, it would have been a small round cylinder style. just up from the tank, mounted on the rear part of the rail. It sure sounds like fuel starvation. Have you disconnected the lined from the filter and pump and blew compressed air through, see if any restriction is there?

 

[Farmer Ryan]

Ok I will see if I can find one tomorrow. It has a hard time starting, but after a few cycles it sputters for a while and eventually starts most of the time. Is there a special to bleed the injectors to help with that?

 

[Longslyde]

No, if it runs, the air is out. The supply pump only cycles a few seconds when the key is turned. so if there's a restriction, it may not pump enough fuel, once it see rpm, the pump goes live. That would explain why it would start after a few cycles. Try turning the key on for a few seconds, DO NOT START, then turn the key off again, repeat a few times and then attempt the start. If it starts quicker, you've found that there's not enough fuel being pumped, whether its the pump itself or a restriction in the line. I had a John Deere diesel mower that acted the same way. Pulled the line and blew air through the feed line. Some crap flew out that I never did find, but it ran like a top after that. Hope thats all it is in your case.

 

[lost1wing]

I worked on this d5c for a friend. He had replaced the fuel filter and had it running again. However, it would just die under any kind of a load.

When I got it, I pulled the fuel filter but didn't see anything unusual. But after pouring out the fuel in a pan, I noticed black/green flakes that looked like pepper. Too big to stick to the filter media and it just sat at the bottom of the filter. So the engine would run fine with little fuel flow, but as soon as load and fuel flow picked up, the engine would just quit. This reduced the flow of fuel and these flakes would just fall to the bottom of the filter and the machine would fire right up.

Ended up being dirty fuel from a contaminated underground tank with a broken fuel filter . The fix was drain and clean the fuel tank on the d5c and replace the fuel filter one more time.

 

[Farmer Ryan]

When I get home from school I will try cycling the key a few times, and if that doesn't fix anything I will probably try to drop the tank and empty it. That should also make it easier to blow out the out line and the return line. Does anyone know that pressure the in tank pump should have? I might clamp a hose on and see if I can get our gauge to read at the pump and see if it is weak while it is easy to get to.

 

[txroadkill]

Before you drop your tank just pop the plug on the bottom.

 

[1BB]

I had a vehicle doing this same thing, and after a full day of troubleshooting, it turned out to be a plugged vent in the fuel cap. The vehicle ran fine at an idle and even up to about 50 to 55 mph for a little while, but soon it started dying and starving for fuel. Pulled over and it would idle perfectly, hit the road again and it would die. Let it sit for an hour or two and it ran fine again for an hour or so and start dying again. Talk about driving you crazy.

I'm wondering since this is seven years old, if your cap might be on the verge of being plugged, and that cold weather took it over the edge and now you're starving for fuel at high speeds?

Next time it happens, if you haven't found the problem yet, pull over right away and remove the fuel cap. If she sucks air, you have a vacuum in your fuel tank and could be the cause of the problem. Hop back in and head out and see how she runs then.

 

[Longslyde]

@1BB That'd be another good catch, I did have that happen on another rig years back. It was a gasser, but same rules apply! pumps aren't good pushing fuel in a vacuum.