Perplexed - loss of power during day, more power at night.

[Tx Jim]

Depending on yr model JD 5425 could have a fuel cooler. If a fuel cooler is present check to be sure there's good air flow through the cooler fins

 

[workinonit]

Maybe ... but I'm not inclined to take any action to find out. Very clearly, my issue seems to change with either ambient air temp or "final" engine operating teimp. Clogging would not tend to improve if running constant but the air temp drops.

OK. Just letting you know that this will cause exactly what you are seeing, I know. I'm guessing that fuel requirements change as the machine heats up and if you are partially starving the engine for fuel it won't manifest itself until temps come up. Just my theory, that's what mine was doing. Doesn't m,atter to me if you check iot or not. Out of all the things to try that I've read it's the simplist and doesn't cost anything to do it. So try everything else first. You would probably be surprised how much crap is in your fuel tank.

If the strainer gets clogged badly enough it will start to pull the priming plunger down on your fuel filter...if you have one.

 

[JimRB]

You also cleaned the water separator? My baby Deere tractor has a separator near the fuel tank that gets clogged up. Another fuel filter closer to the fuel pump. That does not explain liking cooler weather. I replaced my air filter after blowing out a few times. I could see a good bit of bright light through the new filter that I did not see with the old filter.

Google research show some people talk about fuel lines need to be replaced, tank cleaning and fuel filter housing cleaning "Memory, have you ever taken apart the top of the spin on filter housing and cleaned it out? I have seen them plug up with all kinds of nasty #### up there. If you are really plugging that inline filter a lot you may have crap in your tank or be getting bad fuel. If it is fungus get some biocides treatment and use about twice what it calls for for a couple tanks of fuel and treat your storage tank with it also."

By the way I got fuel lines from McMaster Carr for my diesel car. They were for return lines and were silicone based I think. One of my friends was commenting that he had a hard time getting lines from regular car parts places like Advanced or OReilly's.

None of that really explains lower power when hot and better power when the temp drops 10-20 degrees. Well maybe bad fuel lines and they might be expanding internally and choking off fuel supply.

I do know on my car and tractor that the fuel return line has some warm fuel in it. My transmission gets plenty warm brush cutting or finish mowing. Other tasks never generate much heat.

All the radiators have been blown clean? My tractor just has an engine radiator. My Dodge truck has an intercooler, a power steering cooler, or maybe a transmission cooler, a AC condenser and the radiator.

Turbo failure is an off in the weeds thought to my mind.

I cannot find any temperature sensors at the JD parts website.

 

[5030]

Turbo failure is an off in the weeds thought to my mind.

Turbo failure is way more common that you think and most times it will be the failure of the ceramic bearings and seals on the hot (exhaust) side of the turbo. Once the radial play allows the compressor wheel to contact the scroll, it on the way out. I check mine for end and radial play regularly. Only takes a few minutes and a tool to loosen the clamp on the intake side.

With big trucks, you always will have a boost gage to determine if the hairdryer is providing required boost. Not something that is on most tractors however.

 

[Egon]

Cooler denser air at night. Perhaps higher moisture content too.

 

[5030]

OK. Just letting you know that this will cause exactly what you are seeing, I know. I'm guessing that fuel requirements change as the machine heats up and if you are partially starving the engine for fuel it won't manifest itself until temps come up. Just my theory, that's what mine was doing. Doesn't m,atter to me if you check iot or not. Out of all the things to try that I've read it's the simplist and doesn't cost anything to do it. So try everything else first. You would probably be surprised how much crap is in your fuel tank.

If the strainer gets clogged badly enough it will start to pull the priming plunger down on your fuel filter...if you have one.

I will say, between my filler neck strainer I installed last year on both mine plus the Racor style fuel polishing unit and water separator I've installed between the fuel tank feed and the primary fuel filter, nothing get's past it and I can see (at a glance) what, if anything it's collecting, in it's clear bottom bowl and I can easily drain it off.

All diesel fuel is questionable today so why take a chance?

 

[5030]

Cooler denser air at night. Perhaps higher moisture content too.

That kind of lends itself to a failing turbo charger.

 

[workinonit]

I will say, between my filler neck strainer I installed last year on both mine plus the Racor style fuel polishing unit and water separator I've installed between the fuel tank feed and the primary fuel filter, nothing get's past it and I can see (at a glance) what, if anything it's collecting, in it's clear bottom bowl and I can easily drain it off.

All diesel fuel is questionable today so why take a chance?

My point is that if he hasn't checked the tank strainer and at least cleaned it or at best removed it, that could be causing his power loss. I've had it happen on 2 tractors. And the hotter and longer you run it the more power loss. These strainers get completely covered with tank crap.

I removed mine because I have double filters with a water seperator as well. Mine started throwing a low fuel pressure alarm with power loss and turned out that was the issue.

 

[RancherGuy]

OK, I'm back. Great comments. Thank you all.

I'm into raking now, so I'm not running at the edge of available power, but although my autumn is fully loaded, it is an issue I will work on as time permits.

Some questions answered: this tractor is 2006 and simple, but with turbo. Air filter, then turbo, then intake manifold. No intercooler.

Fuel injection comes from the injection pump, straight into the cylinders - no fuel rail.

Metal fuel supply line runs along the engine block, seemingly as much as possible, then comes out to feed the injector. I can't help but imagine the heat it picks up. There is no fuel cooler. Replacing flexible hoses is a great idea - they are original.

I have not checked for water in the fuel filter - good idea. In the 15 years since the enclosed barn was built and tractor stored there, I have never run into water issues with any equipment. It's just not present.

The tank cleaning is a good idea, but a hated task. Did that once - tank is 2 parts and it takes hours just to check.

Thanks for the recommendation on how to check turbo. Seems like a very easy task to accomplish.