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

scrambler73 · May 16, 2015

JimRB said:
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.

So it could be "leaky injectors"????

Do you mean that while the tractor is sitting, fuel is leaking into the cylinders causing a rich condition at initial start-up?

If the injectors are leaking, how is fuel being delivered to the injectors if the key isn't on and the fuel pump isn't running? Just built up pressure?

As for a Injector Cleaner? What specific product have you guys had good experiences with?

The (electric) fuel pump begins making its "pumping noise" (clicking) as soon as you turn the ignition key to "on"

Once again, thanks for helping me work through this!

JimRB · May 16, 2015

Diesel injectors can leak just like gasoline injectors can leak. Leaking can be just a tiny dribble or more. Some of the older style injectors had two pressures for delivery. You can do some Google research on leaking injectors. This guy has a basic explanation. DBW LLC ? TDI Engines and Fuel Systems

JimRB · May 16, 2015

You know that the diesel has pressure, lots of pressure? Diesel Injection Pumps - Fuel Injection Pump - Diesel Power Magazine

Why Diesel Fuel Injectors Fail - Diesel Power Magazine

topstoy · May 17, 2015

scrambler73 said:
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

I have a 2520 but similar starting issue and has done this since brand new. I think, unless it is really cold out, that it starts better if you just turn the key instead of waiting for the light to go out. I was wandering the same thing. With that little inline fuel pump running as soon as you turn the key, could it actually be flooding itself out.

JimRB · May 17, 2015

No, the in-line fuel pump is low pressure meaning a few PSI. The actual fuel distributor makes thousands of PSI of pressure. The injectors are not going to dribble at a few PSI but could at a few thousand residual PSI.

wmonroe · May 17, 2015

scrambler73 said:
As for a Injector Cleaner? What specific product have you guys had good experiences with? The (electric) fuel pump begins making its "pumping noise" (clicking) as soon as you turn the ignition key to "on" Once again, thanks for helping me work through this!

I've had good luck using seafoam, take the fuel filter canister off and dump out the fuel and then refill it with seafoam. Start it up and let it run at just over idle till the smoke clears (there will be LOTS of smoke). I wouldn't do this with the newer common rail fuel systems that run much higher pressure but the older systems that are mechanical and under 10,000 psi it works well.

The reason I said to try priming the fuel system is that sometimes if you have a slow leak the low pressure lift pump doesn't get fuel to the injection pump right away and causes the extra cranking and short rough running you are describing.

jenkinsph · May 17, 2015

I am wondering if the valve guides are leaking a small amount of oil into the cylinders. This could cause the smoke for the initial start up and would clear up when the engine is started up after a few seconds.