Apparently my compression tester has given up the ghost. It'll read, but won't hold pressure. I threw it on there anyway. Doesn't look like I have any totally dead holes. The needle was topping out around the 300psi range for each cylinder. Obviously not super accurate, but they are at least making compression.Compression check would be my starting point.
Not sure if your A/C is still holding but I found with mine after it was converted to 134, the R12 to 134a adapters would cause the refrigerant to leak out very slowly. I'd get a summer out of it but then next year, low on refrigerant again. Was maddening. I did find while trying to locate the leak, that my 6 month old compressor was leaking at the body seal. Then I thought everything was fixed when I replaced that with a new Motorcraft compressor. Nope.
Solution? Take the 134a adapters off after charging the system. Has been 3-4 years now without issue. Blows plenty cold. Also black truck.
Also make sure your schrader valves are in good shape.
Typically, when a pump is totally unusable, it's because the head/rotor clearance got high enough that it won't start when hot(requires complete replacement of head/rotor, the expensive internal parts). This is a true 'failure'.
A more typical "failure" is when the timing gets stuck fully retarded. Not entirely sure why this happens, but over time, the pump will become more and more retarded, or simply 'jump' much more retarded - resulting in blue or even white smoke, crummy performance.
When I have a pump that otherwise works fine, but is doing this, I just pry up the IP gear cover and skip the IP gear a tooth ahead. This gives about 7 degrees of advance, generally enough to get it back into the normal "adjustment range" by rotating the pump. It's a cheap fix that seems to work fine, though sometimes you need to adjust the light load cam from there if it's too advanced down low.
One other failure that I've heard about but not seen myself is the head/rotor actually siezing together. This would be due to a lack of lubrication in the tight tolerances, or some sort of metal getting in the wrong spot. When this happens, the "tang" breaks off internally and the pump drive spins freely. This IP core is basically spare parts and not practically rebuildable.
You also have seals leaking/weeping diesel, which isn't a 'failure' per se, but becomes one of those things you want to replace. Again, something that ordinarally would need replacement, but it's possible to swap seals without too much hassle, especially if it's one that's easy to get to.
Any failed bearing material would be in the housing, not in the pressure side of the pump. It would get returned to the tank and filtered through the fuel filter before getting to the injectors.
Pretty much the only thing that would send material to the injectors would be the inlet vane pump on the input of the IP.
We shall see. Fortunately, it's a thrust bearing, not a side bearing, so there should be no wear on it - I'd expect the only real issue would be destroyed seals if it slid too far out. Remember, the shaft comes out that way, so there's no bosses or other diameters to catch on things and wear.
No, you don't need any special tooling. Just need a vice, hand tools and allen wrenches. The only 'special tool' that you are supposed to need, a tool for removing the inlet cone on the back, well, a open end wrench worked just fine. At least on the pumps I took apart, it wasn't on there that tightly. You could even leave the brass adapter from the inlet hardline still attached to the IP, for added strength there.
I've done it several times. Never had any issues. In my case, it was simply a matter of tearing it down far enough to replace the shaft seals(which is /past/ the thrust washer portion), which I did. Seriously - you don't *have* to take apart every single screw and plunger buried deep in the head or housing - just need to get the main parts out, which limits what you need to put back.
There's also settings like the guide stud in the back which will work "ok" at pretty much any position you physically can put it in; it will just affect drivability - so you can adjust and drive and get it good enough again.
Would it? Most people don't even want to mess with the pump at all, let alone tear into and rebuild one. Instructions are out there, and, well, I followed(most) of it and succeeded... but that was just a re-seal job.
The real problem is that to affect performance and actually make one new, you tend to need new parts or at least a flow bench to modify some of the settings. Otherwise, you just have a fixed, but still worn IP.
Even though some people do, and Mac Robb is one of them, I never recommend skipping a tooth on the IP gear. I'd loosen, not remove, the injector lines and rotate the pump some more. All you have to do is loosen the lines enough that they no longer hold tight to the pump.1. Y'all think I should remove the hard lines and rotate the pump, or jump a tooth?
Use a crow's foot on a short extension. I believe that you do have to remove the line from the fuel filter too do this but may be wrong since it's been years since I've done this.I honestly do not see how it would be possible to just loosen the lower lines without removing the top ones first.