MorrisExcavation Posted September 16, 2014 Share Posted September 16, 2014 I have a 94' CAT 320 excavator with 6600 hrs. Here recently the engine has started to sputter when at full rpm and under load. It is smooth when running full rpm and just sitting or even a light load. When you are digging heavy and pulling in a full bucket it sound as if it bounces back and forth 100 rpm or so and puffs a little black smoke with every change in rpm. I have changed the fuel filter but no improvement. Does anybody have any ideas where I should check next? Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/37108-94-cat-320-excavator-engine-sputters-under-full-load/ Share on other sites More sharing options...
mrsmackpaul Posted September 16, 2014 Share Posted September 16, 2014 governor spring in the injector pump ????????Paul Quote Link to comment https://www.bigmacktrucks.com/topic/37108-94-cat-320-excavator-engine-sputters-under-full-load/#findComment-260090 Share on other sites More sharing options...
hicrop10 Posted September 16, 2014 Share Posted September 16, 2014 Have you ever replaced the injectors?The whole injector pump may need to be redone.Blow out the fuel lines may have some dirt in them. Quote Link to comment https://www.bigmacktrucks.com/topic/37108-94-cat-320-excavator-engine-sputters-under-full-load/#findComment-260095 Share on other sites More sharing options...
gearhead204 Posted September 17, 2014 Share Posted September 17, 2014 does this have the 3116 or 3126 engine? if so the fuel system is set up like a 2 stroke Detroit with a injector rack, I've had problems with a 936 loader doing this and it was wear in the linkage under the valve cover and the link between the rack and pump. Unlike a Detroit, a cat dealer has the special jig tool to set the injectors. Quote Link to comment https://www.bigmacktrucks.com/topic/37108-94-cat-320-excavator-engine-sputters-under-full-load/#findComment-260142 Share on other sites More sharing options...
MorrisExcavation Posted September 17, 2014 Author Share Posted September 17, 2014 I'm pretty sure it has a 3066 engine, i just got it this summer so I don't know of any injector or pump work in the past. It is finishing a barn demo job today and when I get it home I was planning on trying to clean out the lines then have the injectors tested if that doesn't help. I may also drain the tank to make sure I have good clean fuel in it. I had a little issue with water in my storage tank a couple months ago, I have a 300 gal skid tank at my house and the sight gauge was cracked and let some water in. I thought I had run enough through but it may still be showing up. I have a deere dozer running the same fuel and it's not had any trouble. I have drained the water separator on the excavator a couple times and it did not show water but I'd rather drain the tank and start over to know its clean. Quote Link to comment https://www.bigmacktrucks.com/topic/37108-94-cat-320-excavator-engine-sputters-under-full-load/#findComment-260177 Share on other sites More sharing options...
gearhead204 Posted September 17, 2014 Share Posted September 17, 2014 10-4 on cleaning the fuel tank also check to see if it has a sediment trap. if that is a 3306 engine it sounds like the govener and or springs need help. Quote Link to comment https://www.bigmacktrucks.com/topic/37108-94-cat-320-excavator-engine-sputters-under-full-load/#findComment-260200 Share on other sites More sharing options...
85snowdog Posted September 18, 2014 Share Posted September 18, 2014 I would think the barn demo job would be very dusty . Could it be possible the air cleaner has got plugged up?? I wouldn't think so, but an easy thing to check. 1 Quote Keith Link to comment https://www.bigmacktrucks.com/topic/37108-94-cat-320-excavator-engine-sputters-under-full-load/#findComment-260231 Share on other sites More sharing options...
Popular Post MorrisExcavation Posted September 18, 2014 Author Popular Post Share Posted September 18, 2014 I will check that out, it just started on this job so it could be something as simple as that. I'm not usually that lucky for it to just be something simple but it's worth a look. I've spent a lot of money chasing problems in the past and found out it was just something simple. I used to have an old ford 9000 dump truck that was running like crap, man I'm glad its gone! I tested injectors, rebuilt the injection pump, removed the tank and had it steamed cleaned, blew out lines, changed 5 or 6 filters. I was at my wits end and finally had another guy look at it and it turned out the fuel filter base was plugged up. I spent $2000 working on the old truck and all it ended up being was a plugged up filter base. I took the filter base off and put it in the parts washer for 5 minutes and it ran like a brand new one afterward. Sometimes it is simple things 3 Quote Link to comment https://www.bigmacktrucks.com/topic/37108-94-cat-320-excavator-engine-sputters-under-full-load/#findComment-260293 Share on other sites More sharing options...
gearhead204 Posted September 18, 2014 Share Posted September 18, 2014 does it have the mesh fuel strainer? most people never service them . trace the fuel lines from tank to pump and make sure there isn't one! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/37108-94-cat-320-excavator-engine-sputters-under-full-load/#findComment-260299 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.