J D 855 won't start

[Dennisfly]

J D 855 won\'t start

Tractor has been running great for the past 2 years, good power, no smoke, good start if pre-heated when cold. Now it cranks well, puffs a little smoke, but won't fire. So, I checked that it is full of recent clean fuel, changed the fuel filter even though it wasn't very dirty, bled the fuel system 3 times starting at the filter which has a full clean glass with no air bubbles, then to the tap that feeds the high pressure pump, and finally at each injector. Fuel squirts at each injector during bleeding. I used the block heater until the whole engine was warm to the touch, confirmed that the air heater is working, disconnected the air cleaner in case it was restricted, charged the battery and tried again - nothing! Air temp was in the 40's.

Now I'm thinking I've basically eliminated air and fuel, it might be mechanical. Bad fuel pump or low compression.

Any thoughts are greatly appreciated.

 

[XANDROS_user]

Re: J D 855 won\'t start

Dennis, Am going to be very bold and exclaim loudly:ELECTRICAL. Will probly be a saftey switch, maybe the seat switch or pto switch or (depending on your xmission type) a neutral switch. Do you have a repair manual? What year is this 855?

 

[deerefan]

Re: J D 855 won\'t start

If I had to guess, I worked on and old diesel powerpack that was used to power hydraulic vibratory hammers for sheet piling. Same thing...it ended up being low compression. It had been on a job for over a year and they ran it full throttle 24/7 for the whole job. I think they stopped it once for about 15 minutes to change oil and filters. It was flat wore out. How old/how many hours do you have on your 855?

 

[Dennisfly]

Re: J D 855 won\'t start

I'm unsure of the year but I'd guess it is late 1980's or early 1990's. The tach/hour meter has been replaced so I don't know the hours. It has always run well though, and does not use any oil. I don't think it is electrical because it cranks and I have verified that the fuel shutoff solenoid is, in fact, pulling open. I am wondering about a head gasket or burnt valve although it would probably start with just one burnt valve. I do have a manual. In addition to what I have already done it calls for checking fuel transfer pump pressure (4 PSI, I can see it flows but I need to measure the pressure), injector pump timing, valve adjustment, testing compression, and having the injector pump and injectors tested. Minimum compression should be 384 PSI with no more than 71 PSI difference between cylinders. According to the manual, I can visually check the timing (although it hasn't been changed). I need to find a compression gauge with the proper capacity and screw adapter.

 

[wushaw]

Re: J D 855 won\'t start

I would think your on the right track with checking compression next.

 

[roadiestar]

Re: J D 855 won\'t start

I have a 87 855 that would not start, it ended up being a tiny filter inside the fuel pump.
Tom

 

[frank_f15]

Re: J D 855 won\'t start

I would agree with you but i wonder WHY if the tractor has been starting and running well, would the compression go so bad so fast that it won;t even fire?

 

[LeRoi]

Re: J D 855 won\'t start

Running one minute to not running the next with no proir symptoms, plus the things you have already eliminated, leads me to believe you have an injector pump problem. Either it's not putting out enough pressure, or something has slipped internally it's not putting the fuel in at the right time.
Only a fuel injection shop can tell you for sure.
hth
Leroy

 

[normde2001]

Re: J D 855 won\'t start

You might try removing the muffler/exhaust pipe and trying to start. They can get plugged. Also, normally the fuel line attaches to the injector by a "banjo" fitting. You should be able to remove an injector, re-attach inverted on the banjo fitting and crank to check fuel spray. Should be a perfect cone, messy, but effective.

 

[Dennisfly]

Re: J D 855 won\'t start

Roadiestar,

That's exactly the type of information I need. Do you know if that filter was in the transfer pump or the high pressure injector pump? Also, some 855's use an electrical transfer pump and some use a mechanical transfer pump. Mine is mechanical. If the filter was in the transfer pump can you tell me if you have the electrical or mechanical?

I have the tractor service manual but not the Yanmar manual. The tractor manual doesn't mention the small filter. It must be in the engine manual.

Thanks for the tip.

 

[Dennisfly]

Re: J D 855 won\'t start

Frank,

That was my thought too!

 

[Dennisfly]

Re: J D 855 won\'t start

Normde2001,

Pulling an injector and looking at the spray pattern is also a great idea. All kinds of knowledge and creative thinking at Tractorbynet. It never ceases to amaze me.

 

[RobJ]

Re: J D 855 won\'t start

Pulling and testing the spray pattern is the best suggestion so far. I think in this case there is something in the fuel system still causing this. However you are getting some fuel as indicated by the white smoke (which is actually injector atomized diesel). I normally say stay totally away from ether but in this case I would see if it will run on ether. Just a shot or 2 to get it going then a couple more if it starts to see if you can get it running for a few seconds.

You should also check the injection pump timing. Rare that it jumps butit has happened. Fuel in the cylinder at the wrong time would produce this.

Sitting here I just can't believe it's the bottom end. I've seen them run pretty bad. The pics are from my BIL's jd350 crawler I've rebuilt. Number 2 mostly gone (parts of rings missing) and #3 totally wasted. All this and I was using it to push a pad for the garage. sounded bad, little power but it was working on 1.5 cylinders. No problem in the 1 mile crawl to get to my house and back.

Good Luck and keep us posted..

 

[RobJ]

Re: J D 855 won\'t start

pic #2

 

[Dennisfly]

Re: J D 855 won\'t start

Rob J,

Those pictures are pretty bad. I think my bottom end is OK. No pun intended!

I'm going out of town on business for a week and I only access the tractor on weekends, so it may take a while, but I'll definitely let you know what I find.

 

[RobJ]

Re: J D 855 won\'t start

I know about the weekend acess only, same here. I try and build things during the week, then take up. Next is a front bumper. I have the 3" channel, support brackets, holes drilled. But I can't weld because I don't have the proper measurements. I thought of it after my last weekend trip...bummer

Good Luck with it.

 

[jd110]

Re: J D 855 won\'t start

Dennis, I hate to say it, but I suspect you are correct in looking at compression. I have seen alot of these small diesels do exactly what you are describing. They might run great at 380 psi compression, but they wont even start if all cylinders drop below 350. Larger engines like Rob's 350 crawler can run great at 250 psi. It will start a little hard but will run well. I am not sure why this is the case, but I suspect the indirect type of fuel injection has something to do with it. I would look hard at the air filter, filter housing and intake hoses to see if there was any place dirt could have been getting in. Also be sure to check the cooling system. One bad overheating episode can cause a failure like this also. Good Luck!

 

[roadiestar]

Re: J D 855 won\'t start

its in the eletric fuel pump you have to pull the pump apart to
get to it. The book does not show it. My brother has a Deere skid steer fuel pump stoped working,bought a new one started rite up. Later took the old pump apart filter was plugged, same pump as mine.

 

[Dennisfly]

Re: J D 855 won\'t start

I finally got it started. Between my work schedule and the tractor remote location it took a long time.

I talked to a Deere mechanic and he suggested either or using a gasoline soaked rag over the air intake to see if it will run momentarily. If it will, it confirms adequate compression, mechanical integrity, and will help purge any air that may be in the system.

After disconnecting the air heater to prevent a fire, I tried a little either (probably not enough) but it didn't fire. I then clamped a rag over the air intake and squirted it with gasoline where the air would pass through it. With fire extinguisher poised and ready, I then cranked and it started in about 5 seconds and ran for 15 or so. After it ran I noticed an air bubble in the filter glass that had not been there before.

I retightened the glass, bled the filter and started it with gas again and let it run for 20 seconds until it was smooth. I then removed the rag and it started and ran fine on its own. Apparently, I had been sucking air all the time. It wasn't leaking fuel, just sucking air and it didn't create the bubble until it actually ran.

Live and learn.

Thanks again for all of the fine advice.

 

[pruntyc]

Re: J D 855 won\'t start

I would never use ether in my diesel. Its just not worth it, you can ruin one with it. Its not hard to get too much, and with the compression a diesel has it is just looking for bad trouble.