Deere 855 starts a bit rough, clears up and then runs perfect...... ideas?

[scrambler73]

Hi guys,

New here and have a quick question about the 855 I bought about 6 months ago. I bought it from a local dealership that took it in on trade. This dealer has actually sold this tractor 3 times! New, first trade in and then again.... lol.


Anyways, once it is started, the tractor runs excellent. It has less than 600 hours on it.
This is my 3rd X55 series tractor, (755, and another 855), so I am fairly familiar with how they "should" start and run. Thing is, with this particular machine, it has always kind of fought its way to life when started first thing in the morning (engine completely cold).

It's not that it takes a super long time, just a bit longer than my old 755 (fired INSTANTLY) and 855 (took a couple of cranks, but fired as you would think it should) and this bugs me because I know it "could" be better....
This current 855 feels like it picks up on One cylinder............. then Two..........and then finally the Third picks up and finds a nice smooth idle. This all takes about 10-15 seconds every single time you start it cold. If you plug in the block heater it is lessened, but not by much. Starting on a warm day makes no difference either.
Once again, after that initial starting it runs as you would expect a sub-600 hour machine to run. No blow by, Oil is still clean after about 50 hours of my use (my other X55's oil would have turned black by now) and other than the little starting gremlin is as nice a 25 year old machine as a guy could find!


I can tell what I have checked, but I don't know if it means anything?

Since the 855 uses that goofy "air heater" thingy instead of glow plugs, I put a voltmeter to it when starting the tractor first thing "cold" (dash light lit up) and the Volts were 10.5 (+/- .2)

Shouldn't this be at least 12V? or is there some sort of resistor inline to reduce voltage before it hits the "heater"?

Once the light on the dash went out, the voltage did go to Zero, so at least I know the system is working as it should (aside from not knowing if it has enough voltage?)


If it's not the "heater", what else do you recommend I check?

Thanks for the help!

 

[scrambler73]

I kindly received a PM (his message in RED below) from another board member and thought I would post it here in case it might help someone in the future....

I can't offer any help on the engine starting issue, but I can comment on the heater. There is no resistor used in the 12V feed to the heater. The 10.5 volts probably comes about because of various voltage drops in the wire and connectors. Cleaning up connectors and/or using a larger wire to the heater will eliminate some of the voltage drop.

My 790 also has a heater, and it has a manual operate position on the ignition switch. Does the 855 have a heat position or is it totally controlled by the thermo module? Is the heater screen totally functioning or only partially functioning?

As to the 1, 2, 3 cylinder start up, it could be that the valves are out of adjustment or all cylinders don't have the same compression pressures due to valve wear, rings or cylinder condition.



Ok, thanks.

Could it also be that when I take a "Volt Reading" while the heater is working, the resistance going to create "Heat" in that little screen is taking away from the reading at the wire? When I measure volts at the battery terminals it is 12.5-ish.... (tractor not running)

The 855 has an Auto switch.

I have never checked the screen to see if it is fully or only 1/2 functioning. How does one check that? Does the screen visibly "GLOW"? or is there another way to check for full-function?

As to being an engine issue? The way this runs after its initial (first start up of the day) is like new, so I would be highly surprised if there was an issue with uneven cylinder pressures, ring wear, etc. That said, I have never checked or adjusted the valves and that is not a bad idea and will be done at its next service.

One more thing that may be of importance and the more I think about it, "Might" be a possible Cause??? (I'm just throwing things out there in case any of you guys with more experience/knowledge could chime in)

This is an earlier 855 (1989 w/fuel tank in front of the radiator) that has an electric fuel pump instead of a diaphram/pump found on later 855's.

Is it possible that this pump is allowing some "leak down" where it's taking a few cranks of the engine to get fuel back to all three cylinders at initial start up? Does this electric fuel pump/system have a check valve in it? (to keep fuel from leaking back when its shut off) As mentioned in my first post, the tractor starts the same when it's 20 degrees (block heater not plugged in) as it does when it's 80 degrees. With the block heater plugged in, it starts only slightly easier.. Like taking 7 seconds instead of 10...:laughing:

Most people wouldn't complain because it always starts and is really not that bad, I just know how well it COULD (should) start!

thanks again guys.. Keep the suggestions coming!

 

[TractorGuy]

My 855 does not have a visible heater/glow plug screen like some tractors I've seen. It only works when the outside temperature is below 65 degrees and has a light that illuminates on the dash while it is working then it goes out indicating you can start the engine.

I think you might be on the right track with possible fuel leak down. I would invest in a service manual if you plan to work on it yourself.

 

[scrambler73]

Now, I'm on a mission to figure this out! Since making my first post I've been thinking about it all day.....

What about a fuel shut off solenoid that works well enough to start/kill the tractor, but when closed, it isn't really completely closed and has just a "hint" of a leak? I'm still a rookie to Diesels so be gentle, but is it possible for the solenoid to allow just a slight bit of fuel to "dribble" INTO the engine and cause a minor "flooding" condition upon start up?

maybe it isn't "starving" for fuel.....maybe it's actually too rich?

hmmmmmmmm?

I moved the tractor from the barn to the garage today (hadn't started it in a couple of days) and it started a bit rough like usual. I only drove it 300 feet and then shut it off, so it wasn't even close to being up to operating temp.
7 hours later, I went to move the tractor back to the barn and it popped right off INSTANTLY.... I didn't even bother waiting for the "heater light" to go out. I just turned the key and it popped right off.

This is what is pointing me in the direction of a fuel issue

 

[wmonroe]

Fuel filter been changed lately? Does it have a fuel lift pump or does the fuel pump gravity feed to the injection pump?

 

[scrambler73]

Fuel filter been changed lately? Does it have a fuel lift pump or does the fuel pump gravity feed to the injection pump?

Fuel filter is clean. As stated in my first post, the early 855 has a little inline electric fuel pump on it.. Is this the same as the "lift pump"? Once again, I'm a diesel rookie.
:ashamed:

 

[RPW]

Injectors could be dirty / clogged. Might try running injector cleaner and see if that helps. BTW my 5103 will do that when it's real cold.

 

[scrambler73]

Injectors could be dirty / clogged. Might try running injector cleaner and see if that helps. BTW my 5103 will do that when it's real cold.

I will definitely give that a try. :thumbsup: that said, wouldn't the tractor run poorly all of the time though if injectors were clogged/dirty?

Is there a diesel specific injector cleaner that you guys have good real-world results with? I've always had decent results with Lucas products and a few from Justice Bros.

 

[wmonroe]

Fuel filter is clean. As stated in my first post, the early 855 has a little inline electric fuel pump on it.. Is this the same as the "lift pump"? Once again, I'm a diesel rookie. :ashamed:

Sorry I missed that in your first post. Can you hear the fuel pump turn on when the key is on? I would try "priming" the system by turning the key on 3-4 times and letting the fuel pump run. There is a chance you have a very small leak somewhere and it takes a couple seconds for the pump to get fuel pressure to the injection pump again.

 

[JimRB]

If you were serious about this tractor you would send the injectors off for cleaning, leak down and pressure testing. You eliminate leaky injectors then you can move on to things leaking inside the fuel distribution pump.

Biodiesel is a cleaning agent. It can also attract moisture which can get your fuel tank all icky. Or you can stick with commercial diesel cleaning solutions.