i think that might be your best bet.Well, I guess I'll look up the part number for those in my catalog and see how much they cost, but I should probably get them out and check them for numbers before ordering.
I would be willing to bet that you need some work on the IP, your symptoms of air in all the lines is EXACTLY what mine was doing,but you should replace the nozzles,or capsules, first just keep the old ones for spares in case you get in a bind and need one quick, yours are probably still good. I will try to check and see if the fellow that I know down in Ga. is still alive and doing work. He charged me $800 to go through my pump and it was running like a champ when he got through with it. I'm sure it has increased in price now and the price varies on what he actually replaces.I loaded some shale in my dump truck after work. When I load the truck I shut down, go dump, restart the crawler etc. i cut my work short because the 4th time I restarted it the crawler really sounded like it was missing on one cylinder and after idling for a minute it cleared up. So then I drove the crawler about 1/4 mile to my garage. When I keep the throttle under wide open, working it or driving it, I never had the bog down issue. I just got nervous because restarting was more getting more difficult.
I did not change any parts yet.
So I did the test cracking each injector line at low idle. I had bubbly fuel at each line, pictures attached. I think the 3rd and 4th lines sounded a little different, but I made a video so your more experienced ears can check it out. I uploaded the video to my google drive here:
I also sprayed starter fluid around everything while it was idling and nothing happened.
You're correct,all that I know is that if you do it wrong the engine can run away and the parts are not easy to get.No updates, rain has been relentless and I've been tackling some other things.
Looks like the injector capsule 7S9891 is now 8N8796.
What's involved in rebuilding an IP? Sounds like something the average DIY guy doesn't attempt.
I'm scratching my head here--am I missing something?
1. You are getting bubbly fuel at the IP overflow.
2. No real changes to the engine when you loosen the injector lines
3. AND you are still NOT SURE that you are getting pure fuel to the IP, without air.
4---and we are now off chasing parts in the injectors????
Why not take off the fuel line to the injector pump and attach a hose to it, then:
A. See what happens when you hold the fuel above the IP and allow it to gravity feed into the pump, (no more bubbly fuel?) & (how does it run when working?)
B. Put the fuel below the pump and force the IP transfer pump to suck fuel into the pump. (back to bubbly fuel?) & (how does it run when working?)
Those two tests will cost you nothing but some time and will tell you if you have a bad transfer pump inside the IP or air coming in from somewhere upstream in the fuel line from the filter/priming pump/fuel tank.
I must be cheap or something...nobody is going to reimburse you if you have the injection pump rebuilt and find out that nothing changes! The two tests I have suggested will likely allow you to make the decision on rebuilding the pump with some certainty, although it may only be the transfer pump inside the IJ that is bad. However, a decent shop with test equipment should be able to tell you if the transfer pump is bad and be able to document your injector pump performance to see if it is acceptable without rebuild.
Talk to some local loggers or anyone running older CAT machines,someone should know of a private fuel system guy,CAT will want more than you could imagine to fix your pump.Well I appreciate you summarizing it and those suggestions. I was planning on doing some more work on the "suction side" of things before going after inspectors and the IP. I'm grateful for everyone posting all the information though, I have a lot to learn, and yes, I'm very thrifty in general. I was going to replace the hose and primer pump next. I think I can rig up the fuel can as you described, the only problem is the issue was manifesting after 10 minutes of running, so I will have to figure out how to pull that that alternative fuel source test.
Regarding a shop testing the lift pump and IP, would that be a Cat shop or someone independent? If independent, how do I even go about finding someone like that? Everyone local I know either has a new machine or an old machine that never needs a thing, so my local networking hasn't turned up much.