So im back to having fuel problems. Engine looses rpms when it heats up and eventually stalls. Thought it was water in the tank so I changed the fuel/water separator but that actually seems to have made it worse, or I haven't found the real problem. I definitely have an air leak somewhere. Again, Hyundai 130RC3 about 9000 hours, home owner machine so it sits more than gets run. Went out this morning to do some digging and had to bleed the injectors. Hmmm, air leak? Ran for about 30 minutes and then noticed RPMs starting to fall. Ended up dying out in the woods...fortunately, i was able to get off of the MX track. Opened the hood and noticed first two injectors had bubbles right at the base of the injector and engine. Im thinking this is my problem! Is there a seal or O-ring that is supposed to be there? Any suggestions on sourcing a new injector? its a Cummins 4BTA 3.9
Yes there's a seal of some sort in there. No, that's not your problem. There are different fuel systems on a 3.9 and the fuel system is what you're working on, regardless of whether it's on a Cummins or any other engine. IF this has sat a lot, without ever burning a few full tanks of fuel at a time, then there's a possibility you have bad fuel with stuff growing in it and that's plugging up a screen or fitting somewhere.
ok, thought that could be a possibility too. So the air bubbles i saw at the base of the injectors are fine? No where near a diesel mechanic but ive stayed at a holiday inn express! Ill check fuel lines next.
Pull off fuel filter ,see if fuel level is low . If so you are sucking air from somewhere ,check supply pump.
sometimes the answer may be right in front of my face. both fuel lines at the water separator were cracked. Gonna change those and see what happens next.
nope that wasn't it. Shortest run time yet. Gonna replace the two leaking injectors next. I gotta believe that's part of the problem. I don't see any place for a filter or screen. All my manuals are on my work computer so ill look tomorrow. Seems the only place would be on the back side of the engine (where I cant see anything) where the fuel line goes into the hand prime fittings. If I could remove the counter weight, id be able to see everything!
Was the fuel filter full ?
No, it's not fine, but it's not your problem. If you take the injectors out, take them all out and have them tested. 9,000 hours on a homeowner machine, could be anything. Put a piece of clear hose in the fuel return to see if there's air bubbles there, or a pressure/vacuum gauge in the supply to see what the fuel pressure is doing when it runs and when it dies.
Check the transfer pump on the side of the block too. If it has the cheesy cheap one that looks like a gas engine fuel pump, its a good chance it's junk. Have you run any biodiesel in it? I have seen check valve rubber in the "pushbutton prime" transfer pumps swell up and only allow the engine to idle and nothing more.
The injectors seal w/ a copper gasket.. MAKE SURE to get the correct ones.. they make 2 different thickness'.. & NO, you cant just grab one off the shelf from the parts store.. Personally, I would just try to tighten it up while its still in the head.. worse comes to worse, take the inj. out, clean the bore & flip the gasket & retighten.. IF THAT doesn't work, get new gaskets.. TAKE your old gaskets w/ you to Cummins or a fuel shop.. Its not a bad idea to get them tested.. BUT, be prepared to spend several hundred $ when they tell you they're bad.. & they ARE GONNA TELL YOU they're bad.. its just how the game is played.. I don't make the rules.. hell, I wont even play the game.. I bought my own pop tester.. I know a shop that charges 35.00 APIECE to poptest injectors.!!! It doesn't take long to get to the 130.00 I spent on my own pop tester..
Only filter i see is the water seperator, where the lines were cracked. I didnt see this till late so i went back out, a few hours later and that filter was full. Yeah this has the push button type primer that has never worked. Ive always cracked the injectors and turned it over. Dumb question, were is the return line?
Filter may be part of water separator if not it's in there somewhere .Follow fuel line.
yeah follow the fuel line, makes sense! Doh, took the hood completely off so I could see what was going on back there. Forgot about the two filters there. Looks like one of them may be leaking. Time to change those.
Check level in filters when you take them off
finally got back out there. Filters were full. However some knucklehead didn't fully tighten the filter. Yeah that was me! so I replaced the filter (tightened it) and the water separator. Got it purged and started up but died. Purged again and let it run. Since it was getting dark I shut it down till tomorrow to give it a whirl. Dumped the filters out when I got back to the garage and they were both full of brown crap. Hopefully im on to something.
Tank rust maybe.
Brown crap in the filters means a sure bet there's brown crap in the tank, be sure you drain the dregs from the bottom of the tank. I don't know Hyundai machines but I've yet to see an excavator that doesn't have a drain petcock on the bottom of the tank. Also, again, I don't know Hyundai, but some excavator engines use a tiny mesh strainer inside a banjo bolt fitting at a fuel filter, don't know if that's the case with your machine though
finally got out to run it again. ran longer but still died. Think im gonna drain the tank and look into the banjo mesh strainer. Just cant see that side of the engine too easily. Heres a dumb question....do you drain the water separator with the engine running or not?
Not running.
Ok, so I checked the water separator up by the engine tonight. It was about half full of diesel. Dumped what was in the filter into a bucket. Looked clean and refilled with clean diesel. I couldn't get the other filter off. It ran enough to bring it back closer to the house so I can work on it. There is a drain valve but it only drips when its opened. Naturally I have a full tank of diesel. before I go messing with the drain valve, would it be a good idea to pump out the top 1/2 of the tank to save? Another part of my problem may be the old 55 gallon drum ive been using for fuel transfer. Going to upgrade to a new one or stick with the 5gal jug method.
If you know anybody in the fuel business they could dip the tank for you to see how much water is in it
Blow the drain valve out with air, it's either broken or plugged with junk, if it turned then it's not broken. As long as you have a couple inches of air below the filler you can leave the fuel. If you drain it, you don't have to dump it, let it settle and use the top. If you want to clean the tank, take the drain valve out, and pressure wash it, then rinse with diesel. If there's water causing problems then it will be whats dripping. Let it run into your palm if you can't tell if it's water or diesel.
no, dont know anybody. so I was thinking today on the way to work. Besides the drain valve there is also a shutoff valve on the fuel line. I suppose i could drain the bottom of the tank through that valve if the drain valve is clogged. Yes, i believe the drips were water.
I think BLS meant something resembling a lab test to tell you the percentage of "disolved" water. That doesn't matter in the short term with an unknown amount of free water to drain, kind of like drowning and worrying about your cholesterol.
so, I got lucky and my barrel had just enough room for the diesel I had in the tank. Ended up pulling the drain valve off and there must have been a gallon of water in there. Not sure what to do next. There is a round plate bolted to the bottom where the drain valve and the outlet valve is located. May try taking that off and seeing if I can clean out the tank.
created another superfund site this weekend. Yeah there was still 7 gallons of diesel in the tank when i started cracking those bolts that keep the cover plate on. Got it completely drained into buckets and cleaned a whole crap load of sludge out of the tank. Oh and the inlet tube was full of gunk as well. Need to replace the O-ring before i can get it all back together.