Traction 784 - loosing power

[polyfusion]

Hi, having an issue with our 784, hopefully get a few ideas from here.

On level ground (road or grass), the tractor runs ok. Maybe a bit slow at picking up to speed if starting in 4th, but eventually gets there. Going up small inclines in higher gears, you can feel the tractor beginning to loose power, but changing down, we can get the tractor there.

Working in close quarters, I noticed that one of the front wheels went down into a small depression, maybe 6-10 inches deep, and when I put it in reverse (and gear 4), when I let out the clutch and expected the tractor to move, it wouldn't, and when I pressed down on the accelerator, the revs aren't really starting to pick up. Changing down to gear 2, and the tractor was able to move out of the small depression.

When the tractor isn't able to move, the wheels are not spinning, and the engine isn't revving hard; would this rule out a clutch issue?

I changed the 2 fuel filters, and it maybe made a small difference, but not much.

I might have a look at the air filter today, seems like a bit of a job to get to it.

Torque amplifier always in the tortoise position, I didn't try the rabbit position when having the loss of power, might do next time.

One thing I noticed at the fuel pump was that the stop cable was a bit kinked, and the stop lever wasn't all the way to the stop screw, and pushing the lever to the stop made the engine rev a little more, but even after checking this lever is still as far forward as it can be, it doesn't seem to make much difference overall, either before or after seeing this.

Anything else I should have a look at? We will need the tractor to move some round bales in the next few weeks, and hoping we can get some of the power back before then, not sure it will be able as it is.

Thanks for reading.

 

[DLTTrekkers]

Check shut-off link ...to be all the way back ....in run posision

 

[polyfusion]

Have checked that, but still loss of power. Shut off is pushed all the way forward to stop.

We took the air filter out, and there was a big lump of straw in the intake side of the filter, cleaned it out, and retried, still poor power.

So we went out and bought a new filter, maybe a little improvement with new, but still noticeably low on power.

So I decided to have a look at the fuel priming pump, or lifting pump, I see it called a few things about the place, the I&T service manual doesn't mention it.

Anyway, it a "Facet Electric Fuel Pump", looks like this one:

Facet Fuel Pumps - Facet High Performance Fuel Pump, 1/4 NPT fitting 6.5-7.5 Max. Pressure

We couldn't believe the amount of dirt/sediment in it, we could barely pull out the filter it was so jammed with gunk, and there is a magnetic disk in the base that was about double it's size without any gunk on it. Hopefully this is contributing to the issue.

We're cleaning up the filter and the insides as best we can at the moment, but the electrical wire going into the center of the body, the wire going to it broke off inside this housing (it looks like there were only a couple of strands holding it together before I began messing with it) - is there any easy way to get the housing off without doing too much damage? It seems to be crimped on near the main body of the pump.

 

[DLTTrekkers]

Check fueltanktap on rightside for dirt

 

[Quebecguy]

I am not familiar with the 784 but if the manual doesn't mention the pump, it may have been added by a previous owner. Does your tractor run if you simply bypass the pump?

 

[DLTTrekkers]

Check the feed to the filters at the back under the fueltank by loosening the fueltanktap on the rightside and removing the tal ....you will find a lot of dirt in that feultanktap .

 

[polyfusion]

Thanks for the suggestions.

We took off the fuel tank drain plug, and emptied about a litre into a container. There was a few pieces of dirt, maybe around the size of tomato seeds, but it didn't look too bad, other than the large particles, the diesel looked clean, not sludgy (like the stuff in the priming pump filter). The feed to the priming pump comes off a pipe connecting the two fuel tanks together, and comes out the top of that pipe, maybe there is a blockage there, but again, hard to imagine dirt could get lifted up through there, but I suppose it's possible.

Regarding the pump, it looks stock. We cleaned it out, put it back together, and it is working ok. Because the fuel tanks are lower than the fuel filters and injector pump, I don't think the tractor would run without it. I was really hoping after seeing the amount of sediment in the priming pump lower body and filter, that this was the cause of our problems, but sadly not. Cleaning may have improved it a little, but not noticeably.

I ran out of time to do some more checks, but if anyone has any suggestions, I'd be very grateful, I can try them out in a few weeks time.

What we've done is:

- clean out the filter element and lower body in the priming pump
- replaced both fuel filters and air filter
- straightened stop cable so that it returns to the run position fully after starting up.

The tractor does have a front loader (Quicke 2200), and nothing on the back, so it is a bit front heavy. Maybe it's expecting too much to expect it to pull out of a (small) 6-10 inch rut starting in 4th gear reverse. It will pull out better in 1 or 2 reverse, but I would have expected the tractor to have enough torque to pull out in 4th reverse.

A quick question, should these tractors be able to pull off in 4th high on the road, or should we be starting lower and switching up as road speed increases? We've always started off high, and never really had any issues.

On the road, driving along in 4th high, a small incline would cause the tractor to noticeably loose some of it's go. Maybe we will fare better when the front loader is off, and a bale on the back.

The tractor will rev fine and quickly when stationary. It's only when trying to move that there seems to be poor power available, particularly in higher gears.

 

[polyfusion]

Something I probably should have pointed out is that this tractor has a Sekura cab, so it doesn't have the fuel tank mounted behind the driver seat.

The fuel tanks are mounted under the drivers feet, on the underside of the cab, hence why it probably needs the electrical priming pump to force the diesel up to the fuel filters, and onwards to the fuel injector pump. The electrical priming pump is mounted on one of the tanks fairly close to where the fuel comes out into the fuel delivery line.

How is the fuel delivered to the fuel filters from the tank on original 784's? Is it purely gravity with the tank being higher than the filters, or is there any assistance?

I was looking at this youtube video, International 784 - YouTube and I can see this 784 has an original fuel tank behind the driver, but something added to the engine block above the fuel filters, and going to the fuel filters. Looks like a fuel pump, but I've seen other photos of 784's that don't have a pump here; maybe it was originally situated elsewhere, if there was one.

 

[polyfusion]

I am not familiar with the 784 but if the manual doesn't mention the pump, it may have been added by a previous owner. Does your tractor run if you simply bypass the pump?

I had time this weekend to try a few things, and found that if I remove the electrical cable going to the pump, the tractor will run more or less the same as if the pump is connected and ticking away. So it seems as if it's doing next to nothing to deliver fuel through the filters, and on towards the fuel injector. It might be sending a little, as I was able to bleed out the system with the pump on, but maybe it's just not enough to deliver enough fuel when the tractor has to respond to a load.

Does this sound like it could be the problem? Sound reasonable?

I did a little more digging on 784's with original cabs, and the fuel tanks do seem to be either high above the engine, or behind the driver, so with our Sekura cab and the fuel tanks below the filters and fuel injectors, it might seem that the fuel pump is imperative for giving the engine enough fuel to work under load. Otherwise the fuel injector is just enough to run the engine without any load.

Any thing else I should consider?

 

[kthompson]

It sounds like you are doing a good job checking everything. It still could be an air issue but probably fuel or lack of it when loaded. This tractor does not have a turbo charger does it? If so be sure it is working.