J D 855 won't start

   / J D 855 won't start #1  

Dennisfly

Gold Member
Joined
Nov 9, 2003
Messages
273
Location
Lake Anna, Virginia and Alleghany County, VA
Tractor
John Deere 4410
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.
 
   / J D 855 won't start #2  
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?
 
   / J D 855 won't start #3  
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?
 
   / J D 855 won't start
  • Thread Starter
#4  
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.
 
   / J D 855 won't start #5  
Re: J D 855 won\'t start

I would think your on the right track with checking compression next.
 
   / J D 855 won't start #6  
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
 
   / J D 855 won't start #7  
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?
 
   / J D 855 won't start #8  
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
 
   / J D 855 won't start #9  
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.
 
   / J D 855 won't start
  • Thread Starter
#10  
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.
 
 
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