Cat 3204 running rough

Anonymous-0

Well-known Member
I went out to clear some snow with my 931B and it was acting like it was missing. It started and ran good for about 1/2 an hour then started running rough and had no power. After a couple minutes it would clear up and run good again for a little while. It wouldn't rev up enough to move and eventually quit where I had to loosen the injector lines to bleed it. I took the filter off to see if it had water or ice but it looked OK. I put some fuel conditioner in the tank and the filter. Got it going again and it was good for about 15 minutes then acted up again where I had to bleed it. I'm going to change the filter but have never a problem like this before. Any idea's what's wrong? It was about 5 deg's. Celcius out so above freezing.
 
We need to know your budget first. Most of the old ones are a money pit and you need to buy new.If you go to repair it tell us how much you have in it, this is so others will not invest in this money pit. Hire a professional mechanic, since you can't figure it out yourself.
LOU
 
Actually Lou, a professional mechanic was helping me clear snow today and said my Cat was acting like a newer Cummins that gets gummed up with carbon in the same kind of weather but my machine doesn't have any electronics. He suggested getting a new fuel filter and adding some fresh winter fuel. We've had some weird weather here, above freezing to -30C and then above freezing again.

Considering it needs fuel to run and a filter is routine maintenance, I don't think $10 or so is going to break the bank. Just in case I'll budget $30 in case I need some injector cleaner or more conditioner.
 
I opened the drain and not much came out. I'm thinking there could be some crud or maybe a little ice in the bottom. I've got it back where I can work on it easier and I'll stick a wire in the drain and open it up to drain any water. The stuff that did come out was oily like diesel.
 
I've had a total of 4 3204 Cats. One acted a lot like yours just after buying it and getting it home. It turned out somebody had mixed something in the fuel tank that wasn't diesel. Once I emptied it and put in clean fuel it ran perfect. It also sounds like your fuel line could be picking up air, I've had that on two diesel trucks.
 
This one is probably free to fix... find the primary line that goes into the transfer pump on the right side of the engine. Take the line off. If you've got good flow there don't worry about the tank; just close the valve. Now take the next part of the line fitting from the transfer pump. This will have a screen on it. Knock the crap out by banging the fitting on the tracks, rinse in a bit of fuel and reinstall. Chances are you won't need to bleed it and you won't need to change the fuel filter.
You will at some point need to clean the tank.

Rod
 
The machine has been sitting for a few months so it's highly possible it got some condensation in the tank. It's easy to bleed. It doesn't have a manual pump but loosening the injector lines on the pump primes it real quick. A fuel filter isn't a high cost part.
 
If the screen doesn't do the fix the transfer pumps on these have been known to get crap in the bypass/relief plungers and also the springs getting corroded and/or breaking. then its time to take apart and check out the transfer pump. I do have to change the fuel filter on mine at least once a year with only about 50 hours on it. I guess the tank has a bunch of crap in it.
 
If you can bleed a 3204 quickly, it didn't need bled.
I've probably cleaned that damn screen 300 times in the last 20 years. I'm not saying you don't have a frozen line but usually a line freezes solid. When the screen plugs up the engine gets the staggers and if you keep pushing it will usually quit after about a minute. If you let it idle it will sometimes recover.
Most generally, if you don't run it till it quits you just shut the tank valve off, clean the screen, open the tank valve and restart. Very seldom it needs to be bled. Sometimes a couple huffs on the ether button is needed to make it run.

Rod
 
I took the filter right off, emptied it and filled it back up with fuel. Even before I removed the filter, it would turn over and not fire. I wonder if the old fuel may have gelled when it was real cold and even though it thawed out left some wax or other crud in the fuel system somewhere? I didn't go out this weekend to look at it cause we got a huge dump of snow the last few days and the temp. dropped to -25C with the wind chill. This recent weather really sucks!
 
What I suspect is happening on mine... and mabey yours as well... is that there's some moisture in there that is now bering algae that's making the crap in the strainer. I've never dealt with algae before so I'm not sure. All I know is that I fill mine out of the same tanks and buckets as the tractors and the dozer is the only one to have this trouble. We thought at one time that someone had dumped a pile of dirt in the tank but it's been cleaned thouroghly since that time. Mine is also a machine that can sit for months at a time doing nothing.
Just keep in mind that this strainer is a pre-strainer before the lift pump. The lift pump sends fuel across to the micronic filter on that fuel then comes back to the injection pump... so if your filter is empty you have a supply problem before the filter.... Even if it's full... the problem is probably before the filter since the filter is pressurized.

Rod
 

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