2008 TC40DA loosing power

Fields_mj · Jul 21, 2025

I picked up a 2008 TC40DA in Jan to replace my old Ford 1710. Time will tell, but I'm pretty sure it's going to be some of the best money I've ever spent. That said, I do have one issue with it. After its been running for a while (30min to an hour), it acts like its starving for fuel, or developed an air leak. It looses power, and after several seconds, it dies. It will start right back up, but then does it again within a few minutes. The more I keep going, the more quickly it happens. After 4 trys, it's almost instant. If I walk away for a while (30 min), it will run for another 10 or 15 min before the problem comes back. I first noticed it this spring, but it wasn't as frequent. AFTER the problem started, I had some work done to it at a dealership which included replacing some leaking fuel lines. Problem seems worse after that, but I didn't have a lot of time on it prior so its hard to say.

I thought it acted like a clogged fuel filter, so I swapped that out last week and the problem still exists. I do notice that when the machine is running, the fuel bowl on the filter has about an inch of air at the top, but I can't see the fuel bowl from inside the cab (LOVE having a cab with AC), and by the time I get out of the machine after it dies, the bowl is full of fuel again. I'm normally running the machine in the back yard moving logs or totes of firewood, and I'm normally not running over 1500 rpm, often lower. My thinking is that either I have a lift pump that is weak, or I have air in the line prior to the fuel filter and its eventually getting to the fuel pump and injectors. Problem with that is that I'd think that it would pretty quickly work its way out and back through the return line.

Any thoughts or ideas?

Thanks,
Mark

nyone · Jul 21, 2025

Could be some junk in the tank clogging the outlet. Next time it's happening instantly take off the fuel line right below the tank and let her drip for a bit. Low flow there and it dosnt matter how good the rest of the system is.

WM75Guy · Jul 21, 2025

Sounds like an issue where fuel is getting choked off from the tank. After it sits enough fuel flows through to let it run for a little longer. From the tank to the fuel filter, the clear bowl, is gravity fed. Coming out of the bottom of the tank is a pretty small elbow, doesn't take much crud to block it. If that is the case that involves removing the tank and cleaning it out. Also, though uncommon, the cap may not be venting so you get a vacuum in the tank. Easy to test that, trying running it with the cap loose or off while sitting still and see if it stops.

Fields_mj · Jul 21, 2025

I think I had tried running it without the lid on at one point, but can't recall now. I've been worried that there might be junk in the tank or in a fuel line, but it seems like the issue would be more sporadic if it was something in the tank. If its stuck in the drain or elbow, that could explain it. I'm pretty sure the dealership replaced that fuel line, so I'd be a little surprised if there was something in it. That doesn't mean they did anything with the elbow though so its still worth checking. I also wasn't sure if there was anything between the tank and the fuel filter. Glad to know that there's not.

When the machine is running, should the bowl on the filter always be full of fuel? If so, that will be a pretty obvious way for me to confirm the fix because the air appears in the bowl almost instantly when I start the machine. Unless the o-ring on the bowl is leaking some air, I don't understand how that air gets in there.

RobertN · Jul 23, 2025

Sounds like might have fuel supply issues. If the fuel bowl isn't full, then pull the line and run to a clean container. Do you get good flow, not gunk? Check the fuel cap too; it might not be venting correctly.

Even when I change filters, if I don't get the air out completely, it only takes a minute to clear up.

Betting it is the vent, or you have some gunk blocking the hose /elbow where it goes in the tank.

Fields_mj · Jul 23, 2025

If its not normal to have air in the fuel filter bowl, then it sure seems like it has to be the vent or a restriction in the fuel line. I believe that fuel line was replaced by the dealership, but that doesn't mean that it didn't have an obstruction in it, or they didn't get it pinched or something. I suppose it could be that the line is laying such that it captured a large amount of air that won't bleed out, but that seems unlikely and it should be pretty easy to address that issue.

Harry in Ky · Jul 23, 2025

Fields_mj said:
If its not normal to have air in the fuel filter bowl, then it sure seems like it has to be the vent or a restriction in the fuel line. I believe that fuel line was replaced by the dealership, but that doesn't mean that it didn't have an obstruction in it, or they didn't get it pinched or something. I suppose it could be that the line is laying such that it captured a large amount of air that won't bleed out, but that seems unlikely and it should be pretty easy to address that issue.

Fuel Filter | New Holland Agriculture | MyCNH US Store

Find schematics, manuals, specifications and diagrams for FUEL FILTER. Find genuine OEM parts for your needs.

www.mycnhstore.com

Look at return line (item #14) on this diagram. If you have that line on your tractor, then try this next time you put it to work. Pinch the line flat with washers and vise grips or something. Seal the line off and run it like that for an hour and see if the problem goes away.

When ever I find a similar problem on a tractor with that line I snip the line a few inches from each end and plug the stub with a rod, screw, bolt, anything to seal it off. Most engines seem to run better without that line in place. Particularly so if the filter won't stay full.

dieselscout80 · Jul 23, 2025

The line on the top of the fuel filter is allowing air to be sucked in to the filter bowl see the below thread for details. I capped mine off and no issues since then.

New Holland TC45D won't start fuel supply issue

Does it just bolt in? It is next in line after the bowl. I was afraid to take it out.

www.tractorbynet.com

Fields_mj · Jul 24, 2025

Isn't that the return line? I've never had any issues with the return lines on any of my other diesel engines. Seems like capping it off would be hard on the fuel pump and make it more difficult to blead air out after doing any work on the fuel system.

Fields_mj · Jul 24, 2025

Looked up the fuel system in my service manual and found this. Looks like that line tees into the return line that runs from the injectors to the tank so capping it off shouldn't create any other problems. It makes sense that this would be causing me problems. The machine has spent its life outdoors, and a lot of the rubber is getting dried out. The dealership I bought it from replaced what they thought was needed before selling it, and the dealership that worked on it last month replaced the majority of what they could find, but there's always going to be something that gets missed.

I may also try running it up to full throttle next time it stumbles and see what happens. In theory, if there are no blockages, I would think that it should bleed any air out of the system.

Harry in Ky · Jul 24, 2025

It's not really a return line in the strictest sense. It's actually a bleed line. Problem is it also lets air bleed in as well as bleed out. Close it off and see what happens. No harm done.

Fields_mj · Jul 24, 2025

Definitely on my list to try. The only problem is accessing it. Between the loader frame and the cab, I'm not certain I can actually reach anything on the top of the fuel filter. When I changed the filter last week, I had to use a screwdriver and small hammer to loosen and tighten the bowl, and I had to move the ring as far as I possibly could before I stood a chance of reaching the next notch. I never complained about being able to access anything on my old 1710, but WOW are things tight on this machine.

Fields_mj · Jul 31, 2025

Well, its not an issue with venting the tank. I also clamped that hose off with a pair of needle nose pliers, and that didn't seem to help either. The fuel filter bowl still remained about half full while the tractor is running. That fuel line is actually new, but I couldn't see the other lines to see if they were also new or not. I'm thinking its either something clogging the line or something in the tank. I'm getting down closer to 1/4 tank and it seems like its happening more frequently. Kind of seems like I should drain the tank, and remove it, clean it out, and run new line from the tank to the TEE near the fuel filter.

nyone · Jul 31, 2025

Fields_mj said:
Well, its not an issue with venting the tank. I also clamped that hose off with a pair of needle nose pliers, and that didn't seem to help either. The fuel filter bowl still remained about half full while the tractor is running. That fuel line is actually new, but I couldn't see the other lines to see if they were also new or not. I'm thinking its either something clogging the line or something in the tank. I'm getting down closer to 1/4 tank and it seems like its happening more frequently. Kind of seems like I should drain the tank, and remove it, clean it out, and run new line from the tank to the TEE near the fuel filter.

Blow the fuel line back into the tank. Also dont go by the gauge.

My tc40 shut off on my climbing a pile. Then the key wouldnt do anything, no lights or anything. Fixed the poor battery terminal connection then it drove 20' and would just crank. Checked for fuel at the injectors, and low pressure pump, nothing. My gauge said 1/2 tank...well turns out it was empty. 12gal of fuel later and I was back up and running.

Fields_mj · Jul 31, 2025

nyone said:
Blow the fuel line back into the tank. Also dont go by the gauge.

My tc40 shut off on my climbing a pile. Then the key wouldnt do anything, no lights or anything. Fixed the poor battery terminal connection then it drove 20' and would just crank. Checked for fuel at the injectors, and low pressure pump, nothing. My gauge said 1/2 tank...well turns out it was empty. 12gal of fuel later and I was back up and running.

I think mine is the other way around. The gauge was getting pretty low, but 5 gal of fuel almost overflowed the tank.

Harry in Ky · Jul 31, 2025

I would lean towards a restriction of fuel exiting the tank. I think the old "compressed air into the supply hose" trick would be next on the list. See what that changes.

SPYDERLK · Jul 31, 2025

Fields_mj said:
I picked up a 2008 TC40DA in Jan to replace my old Ford 1710. Time will tell, but I'm pretty sure it's going to be some of the best money I've ever spent. That said, I do have one issue with it. After its been running for a while (30min to an hour), it acts like its starving for fuel, or developed an air leak. It looses power, and after several seconds, it dies. It will start right back up, but then does it again within a few minutes. The more I keep going, the more quickly it happens. After 4 trys, it's almost instant. If I walk away for a while (30 min), it will run for another 10 or 15 min before the problem comes back. I first noticed it this spring, but it wasn't as frequent. AFTER the problem started, I had some work done to it at a dealership which included replacing some leaking fuel lines. Problem seems worse after that, but I didn't have a lot of time on it prior so its hard to say.

I thought it acted like a clogged fuel filter, so I swapped that out last week and the problem still exists. I do notice that when the machine is running, the fuel bowl on the filter has about an inch of air at the top, but I can't see the fuel bowl from inside the cab (LOVE having a cab with AC), and by the time I get out of the machine after it dies, the bowl is full of fuel again. I'm normally running the machine in the back yard moving logs or totes of firewood, and I'm normally not running over 1500 rpm, often lower. My thinking is that either I have a lift pump that is weak, or I have air in the line prior to the fuel filter and its eventually getting to the fuel pump and injectors. Problem with that is that I'd think that it would pretty quickly work its way out and back through the return line.

Any thoughts or ideas?

Thanks,
Mark

I had the same type of problem on mine when I bought it. I found plastic shavings and "crap" in the fuel line fitting at the filter AND at least one debris in the tank intermittently blocking the nipple output. I lucked out and got the piece out of the tank by grafting in a 1/4 turn petcock at the nipple. Those are wide open when on, and you can hand spin a drill bit or a screw up into the tank to grab the offender and pull thru. You can also augment by temporarily adding a Tee fitting to try to suck it through at the same time.

Three yrs now and no issue other than filter change.

dieselscout80 · Jul 31, 2025

After using compressed air to clear the line supplying fuel from the tank to the filter mine ran fine. However, this past winter I pulled the tank off and cleaned it.

If you take the tank out and pull the tank exit fitting out and it’s grommet it makes cleaning it easier.

Also I replaced the grommet on mine to ensure I didn’t have leaks.

I plan on adding a pre-filter right below the tank.

Fields_mj · Aug 18, 2025

Update - Obviously this issue hasn't been real urgent for me... lol I tried the whole removing the lid to make sure the vent works. No joy. Vent works fine. I blew air back into the tank from the fuel filter. I could hear it bubbling in the tank. That was one day early last week. I also added some Poweer Service Clear Diesel at the time. I tried to run a camera down into the tank to see if I could see anything, but I couldn't see a darn thing. Too much fuel in the tank still to be able to see anything on the bottom. Didn't really have a chance to use it much until yesterday and the problem returned in about 5 min. Thinking back, when i was blowing air into the tank, fuel never did try to run out of the fuel like like it SHOULD have. I finally got it moved over to the driveway where I don't mind spilling a little fuel on the ground now and then. Pulled the fuel line off at the tank. No fuel coming out. Blew air into the drain, and fuel started pouring out. I had the line off at the fuel filter too so I got it hooked up at the tank, then ran around to the filter and hooked that up as well. Fuel bowl STILL didn't want to fill (it was only half full).

I did notice some junk in it so I started to take it off and drain it. As soon as I had it loose enough for the air to drain, fuel started pouring out so I just tightened it back up. At first I thought I had fuel leaking back from the fuel pump and I started cursing myself for not clamping that line off like I would normally do when changing a fuel filter. I soon realized that I had drained noticeably more fuel than what the pump and injectors could hold so what ever the root cause was, it had now gone away. I only ran it about an hour after that, but it had no issues and the bowl was always full. Since the fuel wasn't draining when I had the line off at the tank, OBVIOUSLY there was/is something in there causing a problem. Once fuel was draining though, I would have expected the fuel bowl to fill without having to vent the air out. I would have expected the line on top of the fuel filter to vent the air back into the return line. Am I missing something there?

FWIW, I changed the fuel filter about a month ago. That was the first thing I did to try to address this problem. The problem has gotten progressively worse sense then (until yesterday). The PO used the machine to maintain his deer lease so it sat for long periods of time. I'm wondering if he didn't use some fuel with Biodiesel in it, and I'm dealing with algae. I have some work to do with it tomorrow. When I'm done, I'm going to go ahead and drain the fuel filter again to get the crud out of the bowl. I'll also pick up some Bio Kleen on the way home tonight and add that to the tank before hand.

Harry in Ky · Aug 18, 2025

Seems to me if you had algae in the system you would see some of it with all the lines and such that you've had apart. Something in the tank (or the fuel filter inlet fitting) is likely yes, but algae? When I've found that it's been some black, slimy, sort of stuff. Hard to miss.