"Whitedog" wrote:

$165/Hr! Is that Canuck money or real money? I don't know anyone around here that charges that much.

Now I'm wondering if there could be blockage between the feed pipes under the pumps and the pump chamber. If I can't get good fuel pumping out the pumps, I think I need to pull one to see. Squatch has that video and it's nothing big, but one thing I noticed he did but didn't mention because it's so natural to him is that you want to hold the plunger into the body as it's removed. I noticed he would push it up, then hold it with his pinky once he couldn't hold it from the bottom.

There is a rubber O ring under each of those pumps, if you are lucky it will reseal, if not part number is 2A3307, they are a couple of bucks each from the Dealer, though Cat says it is NBR 75, inside dia 0.31", cross section 0.19"

I'm with Neil on cleaning everything in that fuel system, the photo you showed us of the one way valve in the transfer pump was disgusting, and I suspect the pipe to your fuel pressure gauge is probably choked with old crud too, double check the 2 gaskets you replaced on top of that fuel tower are the right way round, you wouldn't be the first guy to get them around the wrong way because they look identical, one has a small bleeder hole in it.

The Ford and Toyota Dealers in my local town charge $165 a hour, I've never used the Cat Dealer Mechanics because the one time I asked for help years ago they admitted they had never touched a D2, nor had the tech books for working on one, but I suspect they would be in that same range, plus mileage.

Mike, I have the factory gauge off and using my own gauge since the factory one is no good, so that isn't affecting my readings, but I'll make sure it's clear just so there isn't any crap in the system. I'll also triple check the gaskets, though I'm sure they are correct.

So here's another theory on why it ran then didn't. It sat for a long time and gunk built up in the tank. Running it got that gunk stirred up and it was finding it's way through the system, blocking passages. They shut it down and everything settled, and now it's starved for fuel.

Neil, will pulling the fitting just above the TPump clean out the bottom of the filter housing?

Right now my plan is to get the TPump back on, make sure the filter housing is clean, drain the tank of all of the old fuel, new filters, open all of the pump bleeders and blow air from the filter housing out the bleeders, watching for gunk. New fuel, and see what I get out of the pump. If still nothing, then pull at least one pump and inspect it looking for gunk or erosion/corrosion on the plunger and barrel.

I’ve experienced sudden failures of hydraulic gear pumps. Seemed that the pump was fine when the machine was shut down but wouldn’t prime itself the next morning when it was started up.

It’s not the same level of precision as your injection pumps, but just pointing out that if some abrasive crud got by the filters it wouldn’t take long for it to ruin the pumps and possibly injectors too. There is something (algae/bacteria) that grows in diesel. This crud, as I’ve experienced it looks like black/ brown mud. Usually it just plugs filters, but maybe it’ll damage or plug pumps too if it gets that far. It’s possible the tractor had a tank full of contaminated fuel and it ran long enough to plug the filters as they were loading it on the trailer, so it wouldn’t start back up and it has been like that ever since.

I also have found sediments, (stuck mostly) in the injection pump fuel gallery. I think blowing back and forth with air is a good way to stir and loosen anything in there up. At this point unless your injectors are spraying a good pattern I think I would clean the whole system from filter tower to injection pumps.

So nothing good going on. I have cleaned everything from the TPump to the pump bleeders and still nothing. I drained almost all of the fuel and put in a fresh five gallons and there is no pressure on my gauge at the gauge port.

But even if the pump plungers were all shot, I should still get base pressure.

I pulled my pressure gauge hose off of the adapter on the filter tower and while cranking, I get a little bit of fuel out there and I put my finger over the end and held it there for a minute or so and when I removed it, it spurted out in a fast stream. I'm not sure what this tells me.

I wonder what I could learn if I blocked the port in the filter tower going to the inj. Pump.

If you’re sure the pressure relief poppet, spring and seat are good, then your pump may be worn too badly to build significant pressure. The other thing is if the filters were plugged, you would get low gauge pressure or low flow out the gauge port because it’s after the filters. As a quick check (if it has one) open the bleed screw on the filter tower below the filter mounting plate and compare pressure there to the gauge port after the filters.

The problem with the transfer pumps is they get to pump any rust and grit rom the bottom of the tank into the filter tower or even out the bypass/relief valve and back into the inlet of the pump. Doesn’t take long to ruin a gear pump when it’s pumping abrasive debris.

However it really doesn’t take a whole lot of pressure to get the main engine started and sometimes the higher rpm of the running engine will bring the pressure up enough for good performance. After all it’s not like a Cummins PT or a common rail system where the supply pressure to the pumps controls their output. If you have enough pressure you’re good to go and more isn’t going to change anything.

Now I'm wondering if I could install a pump right at the pressure port and feed it separately. Shut off the fuel at the tank so it doesn't just feed back into there.

You need to filter the fuel so it needs to go in below the filter plate. How about plumbing it in the filter housing drain plug as a temporary? source.

Or simply cut the line between tank and transfer pump and put your add-on in there. The type of pump may be an issue either way. If it’s a positive displacement pump it has to have a bypas to prevent it either stalling and burning up or blowing gaskets etc. Then there’s the problem of power supply for it. What does your tractor have for an electrical system?