Cat 3204 running rough

Anonymous-0

Well-known Member
Need some more help with a problem I posted about a while ago. Finally had some nice weather to work on my 931B with a 3204. The machine started right up and I let it run for about 5 minutes before shutting it off and changing the fuel filter. I filled the new filter with diesel and the machine started right up without having to bleed anything. I then used it for about 1/2 an hour and it started loosing power again. Letting it idle cleared it up but it would act up again. I got it back to where I could work on it and it stalled and couldn't get it to even fire. Every time before I could loosen the injector lines and it would start right up.

This machine does not have a hand primer. I loosened the injector lines at the pump and seemed to have fuel there but it wouldn't even fire. I loosened all the small fuel line fittings and they all seemed to have fuel. Looking in my manual(which shows a hand primer I don't have) it says there is a screen in the fuel shut valve off at the tank. I was told on here that there is a screen at the transfer pump as well. Which line at the transfer pump has the screen? One fuel line goes onto a big nut threaded into the pump and the other one has a longer hex (1") fitting the line connects to. I didn't want to take anything apart in case there were O-rings or other small parts that could get lost. It's also a bit of a pain to work on because the loader arms are in the way. Any help would be appreciated.
 
Stick I have mixed a little (50/50) gas and diesel and take something like a windex squirt bottle. Get someone to hold the loader lift control to lift. As you spray the mixture in the breather. It should hit enough to get you loader raised. Then you can get a safety bar on the lift cylinder. After that go to work on the fuel system. You have something stopping it up. Start at the tank and work forward.
 
Transfer pump should be located between the engine oil filter and the oil cooler. You should need an 11/16" and 9/16" wrench and no more. IIRC, you'll see a larger line (mabey 7/16") with an elbow that feeds into the transfer pump. This line comes from the tank. Above this line will be the outlet line from the transfer pump and this feeds over to the main fuel filter on the left side of the engine. Basically... remove the larger line from the elbow. Then remove the smaller line above that goes to the filter. Then remove the elbow. There will be an o-ring on the elbow but it's common. Next you remove the longer hex piece... this is the screen. Also will have an o-ring... again, common. Now... if you didn't have a large flow of fuel when you removed that first line, trace it back to the tank and find out why. Otherwise, clean the screen and reassemble. Here is where the fun starts.... and you'll damn well learn to NOT do this again... Take the filter off and fill it. Remove the 3/4" hex bolt/bleeder on the TOP REAR of the injection pump. Now with the shutoff pushed forward/off, crank the engine until you get clear fuel from the bleeder and reinstall. THen... open the lines at the injectors and make sure you use two wrenches... one to hold the fixture and one to remove the compression nut... otherwise you twist the injector lines off inside. Now set the throttle to max delivery and crank. I probably wouldn't be too shy to pour some ether to it to help with the cranking. When you see some good blasts of fuel coming out at the injectors or on the drip rail that runs along the head... start closing them up and keep cranking.
I hope your batteries are good. If they're not, make her run on ether while bleeding or it will never get bled.

Rod
 
If you filled the new filter you might have got dirt inside of it. Anyway it s starving for fuel
Runs at idle but can t carry a load. The transfer pump might need check valves.
Later Bob
 
Trade it for a OC46 gas crawler.Ours is still working,while yours is sleeping.lol.
LOU
a109339.jpg
 
I've ran it out of fuel before and it wasn't too involved to prime. The fuel lines all look the same size. The fuel pump is on the bottom of the injection pump. I'll take the longer hex piece off and clean the screen. It's the lower fitting. Some of the fuel lines are hard to follow because they go behind the filter. When I emptied the old filter, the fuel was green colored, then black colored when almost empty. The green color might have been from the fuel conditioner and the black maybe from dirt that had been filtered? It has an 8D battery but it's getting old. I can boost it though for faster cranking.
 
What vintage is this machine? It may have a different pump than the sleeve metered job on mine... but I've never found it easy to bleed when it's actually out of fuel. If you catch it and stop when it gets the staggers, you can clean the screen and it will restart without bleeding, but if it full out quits... it will take a while.

I'd say the black slime, etc is the result of water and probably algae in the tank. Dunno about the green.... unless it's dye in the fuel. Around here some suppliers like Ultramar dye their road fuel green.... and I mean GREEN like St. Patty's day beer.

Rod
 
I have always bled my filter by the method in my maintenance manual--the top of the filter housing has a bleeder screw on the left side . I open that and let gravity feed until no air bubbles. Never had to crack an injector.
 
Fought a 3208 for three years acting like that. Finally found a small crack in the fuel line from the filter to the pump. Would run for days and then not for 15 minutes. Sucked just enough air to stop running. Swede
 
It's a Japan built 1986 with the improved 3204 DI. I think the fuel conditioner was a green color and the black maybe from dirt the filter picked up? Before when it quit loosening the injector lines on the pump was enough to get it going again. The fact I had it running when I last parked it and it started right up yesterday after sitting for a couple weeks would indicate something may be blocking fuel flow. I think if it had a leak somewhere it wouldn't have started so easily after sitting. I'll clean the screens at the lift pump and the fuel shut off and see if that's the problem.
 
Mine doesn't have a filter bleeder that I can recall. It wouldn't much matter if it did or not. Even bleeding the top of the pump manifold is insufficient when it really air locks... Mine is an 87 D4H with the Mitsu/3204T

Rod
 
yep--lots of different arrangements--mine is a 1987 D3b, Mitsubishi, engine serial 45v51332, arrangement 2w7487.
no primer pump, filter bled,
constant fuel delivery problems since i bought it in 2008
can"t find any way to get to a possible screen in the fuel tank
 
This machine has a different pump than the one you describe. There is no 3/4" plug on the top. I have good fuel flow to the transfer pump. I took the fuel line off the elbow on the hex (transfer pump screen) and then removed the elbow and screen at the same time. The screen had what looked like brass slivers sticking out of it. Further inspection revealed them to be some type of strong fibrous material. I pulled out as many as I could and then sprayed some cleaner in the elbow on the other end. I blew through the elbow and it seemed to have a restriction like there's a smaller orifice in the hex part or the fibers are a finer screen. It wasn't plugged solid though.

I put it back together and tried it out. I didn't have to bleed it cause I already had it running. I had the fuel line loose and turned the machine over just to lift the boom a little and it fired so I tightened the fuel line and loosened the injector lines to bleed it. It started right up so I lifted the loader all the way up and put an angle iron on the cylinder. It ran good for 45 minutes this time but then started acting up again. I limped it back to where I could work on it, took an hour to move 1/4 mile! When it would die or almost die, it would have puffs of black smoke for a few seconds then clear up and rev faster. When under a load it would just bog right down. Could it be a check valve problem or in need of a new transfer pump? Never had any problems like this before.
 
I am going to pull my transfer pump apart as a cat mechanic told me the check valves and/or springs inside can get gunked up and the springs can corrode and break.said it was common on the Mitsubishi transfer pumps.
 
If the screen is staying clear and you have good flow to the transfer pump then I'd say the transfer pump is the problem... Check for a bleeder on the filter housing if there's none on the pump manifold. Open the bleeder and see if it will shoot fuel when you crank. It should...

Rod
 

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