I bought this machine last year to do some work around my house. It's got 2900 hours on it. Ran like a champ when I got it. I've only put about 75 hours on it in over a year. I loaned it to a friend and when it came back it was running rough with a loss of power at mid to high RPM. It starts right up quickly and idles perfectly but when I increase the throttle, it gets rough and loses power. I'm trying to start troubleshooting this because I need to use the machine for some drainage work in the next month. This machine was the Isuzu 2.2l 4LE2 motor. I have ordered new air, fuel and oil filters and will be installing them next week. I'm hoping it's just something simple like a clogged air filter but we'll see.... If anyone has any input on how to diagnose this issue, I'd be very grateful.
Most likely a fuel issue, first thing to to do probably is find the fuel tank drain plug and drain a pint or so into a glass jar, or a clean container and then pour it into something that's clear glass. You're looking for a separation if there's water, dirt and debris, coloration and smell of the fuel. You never know what somebody will pour into it, or what their fuel can had in the bottom of it. If the fuel looks decent try running it with the fuel cap off, just to eliminate a clogged vent as an issue. Remove the fuel line from the tank, with the cap off blow low pressure air back through it in case there's a blockage. Also if the fuel line attaches to the pump with a banjo bolt, check the banjo fitting for debris and look closely at the hollow center of the bolt, some Japanese machines have the infamous tiny screen screwed into the hollow passage in this banjo bolt, it's the first thing to clog up if you get gunk in the tank. Of course change fuel filters after that, and hope it clears up. By the way, since you don't seem to run it a lot, make sure you keep the fuel tank topped up just as close to the cap as physically possible, the less air the less condensation and oxidation. Also use a good diesel biocide to keep the algae growth to a minimum.
lantraxco - Thanks so much for the great advice. My new filters came in today and I went to work int he machine. I started by pulling the water separator and fuel filter bowls. The separator has a plastic screen filter in it and it had a lot of rusty crud in the bottom. The separator bowl had some too. The fuel filter bowl had rust crud in the bottom too. The fuel filter was relatively new (about 100 hours on it) and it was a quality Donaldson piece. It didn't look very dirty and I'm hoping that it kept my injectors and pumps clean. I cleaned the bowls and screen filter thoroughly and installed a new Donaldson fuel filter. I then pulled the tank access cover on the bottom of the machine and found the drain valve. I got a quart sized ball jar and drained about half a quart of fuel into it. It was murky and nasty. I didn't see any water separate but there was lots of rust and crud in there. It was murky at first but then settled out on the bottom. There was not a banjo fitting on the bottom of the tank or any fuel lines. Also, the ball valve didn't flow as fast as it should which tells me that it's gummed up. I'm guessing that the cause of my problem is that the engine is not getting enough fuel at higher RPM. My next step is to drain the whole tank, flush it out, flush the fuel line and vent line and then put some fresh fuel in there and see if it runs right. I'll be sure to keep it full and use a biocide. Any ideas on how to flush the tank? I can't remove it from the machine so it'll have to be done in place. Is it okay to flush it with water? Thanks again for the help.
I wouldn't use water I don't think. Pull the fuel cap off for venting and drain the tank, if it starts to look fairly clear before the tank empties I would call it good and just put some clean diesel in. The separator and filter should keep any gunk that remains out of the system. Typically the fuel pickup is above the bottom of the tank by a couple inches just to leave the stuff that settles out on the tank bottom. Maybe make it a habit to drain a pint off the bottom before you start it if it's been a while, though having to remove cover to get to it sounds like a pain. The banjo fitting I mentioned would be on the engine, at the end of the suction line coming from the tank, or the line from the water separator to the transfer pump, at the pump, if it has one. The newer engines may have a completely different setup than what I'm used to, lol.
That's a very good point about using water if the pickup on the bottom of the tank is an inch or two above the bottom of the tank. There would be a lot of water in there before it actually started coming out. I'm thinking I'll try running a magnet wand around the bottom of the tank and see if I can pick up some of the rust. I'm also thinking I'll get another pump and try to pump out those bottom few inches.
The drain *should* be in the lowest point for the express purpose of draining water that's separated out, the pickup for the engine should be higher, if all is according to plan..... You need the patented Willie59 suck bucket! Much discussed on some threads here...
You could also open the possibility and drain and run a piece of mechanics wire up through it to loosen any crud sitting above it, I've had good success with this, then do what Lantraxco said, let it run till you see clear fuel.
I got the tank drained. When I opened the petcock under the machine, the fuel came out slowly which again indicated that there was gunk in there. As well as having the drain open, I used an old in tank pump from a car and pumped the diesel out, through a filter assembly and into a few clear containers. The fuel all looked good when it came out and was filtered. There was a bit of stuff in the bottom of the tank but it wasn't bad. It had accumulated in the petcock drain hole which was why it was draining slowly. Once it was all drained, I disconnected the fuel line from the supply tube (which does pickup fuel an inch above the tank floor as you stated) and cleaned out both the drain and the supply with wire and brake cleaner. I then put the filtered fuel back in. I ran the machine for half an hour at 2/3 throttle to pull a tree stump and after about 15 minutes, it started losing power and running rough again. If I put the throttle back to idle, it would smooth out. I would then bring it back up to 2/3 and it would smooth out for a little while and then lose power and run rough again. I took a look at the fuel/water separator and fuel filter while it was running and was surprised to see that they were not full. Here's a video of them: http://www.youtube.com/********=2nYZrEwFv7U The separator was about half full and the filter was only full to the bottom of the filter. I read in the manual for the Isuzu 4LE2 motor that there are both self bleeding and manually bled fuel systems. I'm not sure which I have or how to tell. I know that it was recommended to remove the fuel cap while running the machine and blow through the fuel line. I didn't run it with the cap off but I did remove it numerous times while it was running so check the fuel level and it didn't seem to make a difference. While I had the fuel line off, the fuel supply pipe looked totally clean and no gunk came out of the line so I didn't blow through it. Think I still need to do these two tests? I'm not sure what to do next. This is so frustrating!
Couldn't get the video to play, think HEF mucked up the link. You've got some air in the system which needs to be bled, but I should think now with the fuel tank and lines clean, you need to move on through the fuel system from where the fuel line connects to the water separator right through to the injection pump, somewhere you have a clog I'm betting.
Agree with lantraxco...on my kubota engine, I have a bleed tap (round knob) for getting air out of the lines (not the air screw on fuel filter housing). Whenever I changed out fuel filter, sometimes I`d have rough idling situation. Turn the knob, reprime system, close knob. and it would be ok (or something like that)...knob was up near fuel pump, if that helps. Does sound like you have crud in system though.... Lesson#1 - never lend your machine out...lol
Good advice on this thread for sure! On my New Holland tractor I would have this happen when the engine was starved for fuel. So, I would say that it is definitely your problem and that you are on the right path to getting it resolved. Purging the air is critical. Check all the fuel lines and banjos. You might have to crack more than one to get the air out. You may also have to crack the injector lines to get the air out going to the injectors. I would also bet that there might be dirt or grime in your injection pump. Keep in mind that diesels use super high pressure on the fuel. So if something isn't perfect, it's not going to work. I personally would not run this machine any more until you sort out cleaning the injector pump and then getting the air out of the injector lines. Then you should be golden. Unless your buddy was dumping dirt in the tank, I doubt he did anything to your mini... I bet dirt from over the years just made its way through the system and it just happened to get ugly when he was using it... But yeah, I'm not a big fan of loaning out stuff. Best of luck getting things back up and running. Maybe try to post your link directly into the thread. Keep us posted.
Incredibly useful. Thanks. Having trouble with my IHI digger. Problem after loaning out… thanks again!