Deere 6420 rough running

[Jeff Thomas]

I have a 6420 4wd that runs fine most of time. However, every once in a while it runs rough sounding as though air is in line or it has bad fuel. If you turn the tractor off then on again its solved the problems mist of the time. Changed the filters and checked for air but still does it every once in awhile. I called a John Deere mechanic and he said it could have something to do with a sensor in the fuel injector pump. They are 3000 dollars. Anybody have similar problems?

 

[jenkinsph]

Sometimes air leaks can be hard to find and intermittent too.

New fuel pumps are expensive but doubt this is your problem at least it should not be necessary to replace it. Most people try to find a good reputable injector pump shop and have the pump rebuilt and adjusted to specs. Even the typical Deere dealer sends the pumps out to be repaired just as starter and generators are sent to their respective shops.


I would go over all the lines with a fine tooth comb, clean everything up well so you can see if it leaks fuel. I would also check the return lines to make sure none of them are stopped up. Tighten all the tubing lines with tubing wrenches to specs. I had a fuel siphon pickup tube (in the tank) in one of my tractors develop a small crack in it, it about drove me crazy sometimes working ok and other times not. Recognize that from the 1st stage fuel transfer pump back to the tank the fuel line is at a slight vaccum so if any thing is loose or pin holed it can draw in air ( air entrainment). If nothing seems to work after checking the above I have spliced in a piece of fuel grade clear hose at the main transfer pump outlet to see if any air is being entrained. Should also add that the transfer pump diaphram can have a pinhole in it too. Check the tubing when you are having the rough running.

Next and only after trying the above I would remove the injector pump and send it in for service. They do need to be rebuilt occasionally but rarely need to be replaced with new.

Keep us posted on your endeavor.

 

[JESSE1]

The fuel line from the tank to the filter has a bad habit of going bad after a number of years. Your tractor is still pretty new but I'd recommend changing out the fuel line. My 6400 started getting air in the filter any time it sat for a day. The fuel line was seeping just enough for air to get in it. Changed it out and no more problems.

 

[FMcCool]

Yes, about exact same as you. I have '03 JD 6320 doing the same and dealer does not seem to know how to solve. Made similar changes, fuel filter, check valve, and fuel shut-off solenoid all replaced to no avail. Going to contact someone at JD Hqs. at this point.

 

[FMcCool]

Follow-up note; I expect you already checked fuel injectors by backing off on individual lines with engine running. Resultant loss of power would show that the injection pump is good. Also would assume you checked that primary and secondary air-filters are good. Do you have any check lights showing when problem arises? I do not.

 

[sixdogs]

The fuel line from the tank to the filter has a bad habit of going bad after a number of years. Your tractor is still pretty new but I'd recommend changing out the fuel line. My 6400 started getting air in the filter any time it sat for a day. The fuel line was seeping just enough for air to get in it. Changed it out and no more problems.

Bingo. I have a six? year old 5520 with same(?) engine--and spent agonizing hours trying to figure out the same problem.
It was a rotted fuel line that I didn't realize had a slow leak from rubber-rot cracking.
Rather than the gamble of another line at Deere I got the correct line at NAPA and hope the quality is better.
Mine is an open station tractor and the line was not a straight shot and very difficult to change. Maybe three hours?
If the fuel line is OK, I like the idea of calling JD at the home office.

 

[Jeff Thomas]

Yes, about exact same as you. I have '03 JD 6320 doing the same and dealer does not seem to know how to solve. Made similar changes, fuel filter, check valve, and fuel shut-off solenoid all replaced to no avail. Going to contact someone at JD Hqs. at this point.

Let mrs know what you find out

 

[bchambley]

I have 3 tractor with the same engine. It seems that around 2,000 to 2,500 hours the injector pumps start to give problems. I have had to rebuild all three. The cost was around $1,000. All tractors have done exactly as you described, and the rebuild solved the problem.

 

[Jeff Thomas]

I have 3 tractor with the same engine. It seems that around 2,000 to 2,500 hours the injector pumps start to give problems. I have had to rebuild all three. The cost was around $1,000. All tractors have done exactly as you described, and the rebuild solved the problem.

Where have you had them rebuilt. Also is there any issue reinstalling them.
Thanks

 

[REGRACO]

WERE YOUR PUMPS ELECTRIC STYLE ?

 

[HallFarm]

I have the same fuel problem. Checked everything. Diagnostics say solenoid bad in injector pump. Dealer suggest putting a rebuilt one on. He also stated they are having a lot of problems with these injectors. Seems John Deere would make them right or at least help. Please let us know if you have any succes with corporate!!!

 

[Tx Deere]

If your fuel filter has the glass sediment bowl on it make sure the gasket is still between the filter and the sediment bowl because it will run fine for a while before it starts to suck air from here without leaking fuel also just go ahead and replace all the fuel hose and replace the squeeze style hose clamps with good screw type

 

[HallFarm]

Thanks TX Deere, we have checked all those things and replaced all fuel lines. Talked with the dealer again yesterday, my problem is not the first to to come through that dealership. Several more have had the same issue. Only thing that seems to fix the problem is a new injector pump. They stated that Chevy had used the same pump on some engines and were experienceing similar problems. Seems pump replacement is the only option. I have truly tried every other potential issue to no avail. Will let u guys know if it works, I have one on the way!!

 

[Jerry/MT]

I have a 6420 4wd that runs fine most of time. However, every once in a while it runs rough sounding as though air is in line or it has bad fuel. If you turn the tractor off then on again its solved the problems mist of the time. Changed the filters and checked for air but still does it every once in awhile. I called a John Deere mechanic and he said it could have something to do with a sensor in the fuel injector pump. They are 3000 dollars. Anybody have similar problems?

It sounds like fuel delivery issues. I would make sure that you don't have some crud in the fuel tank that's clogging the tank outlet and/or fuel line itermittently. With low fuel in the tank, you might consider removing the drain collecting the drained fuel and seeing what you have in the tank. It might surprise you! Water and algae are common problems with diesel fuel. Was there any evidence of debris in your fuel line or the filter when you changed them out? (I bought a used tractor out of New Mexico and I had aproblem ith water in the fuel. It surprised me because the humidity is very low there but the PO might have had a contaminated storage tank.)

My neighbor has a 6420 and he's had a lot of problesm with lift pumps (multiple replacements) but as far as I know, that has resulted in an inability to start. However intermittent operation of the lift pump can cause a problem with fuel delivery.

Make sure all the fuel connections are tight so they don't suck air.

Don't replace/rebuild the pump until you have eliminated all the more likely possibilities.

 

[tjnoonanndt]

if tractor is common rail do not open injector lines. if it is common rail it sounds like a suction control valve your jd mech prob checked codes look out for ecu 1347.07

 

[mini]

I have a 6320 that on a cold day after the first startup of the day it will run for about 10 minutes and then start missing badly. Shutting it down for about a minute or two and recranking solves the problem for the rest of the day. This tractor never has this problem on a hot day or during the summer. Anybody had this problem?

 

[MBBuilders]

I know this thread is old. but if anyone is still having problems. I purchased a 6420 in 2016 it was a nightmare.
Hi eng temp, hi trans temp. injector pump solenoid And every other code possible, (28 in total) all at different times. it run for weeks then out of the blue it would start running rough then stall, it would start up run for a few seconds and die, Jd tech re programmed ecu, it ran for a few days and started all over again, I found the problem last summer, there is a short wire harness going from ecu into the cab 16 inches long had a tiny nick in the wire and would short out. replaced wire all fixed

 

[beenthere]

had a tiny nick in the wire

How in the world did you find that nick? tks for posting your "find" and solution. Nightmare for sure...

 

[MBBuilders]

It was by chance, after Jd tech come out and his fix didn't work, desperation set in. I knew it was going to get real expensive so started chasing wires starting at injector pump. everything looked good, then open up fused panel and started pulling on plumes of wire and would hit the key. the third wad of wires I wiggled around it popped off played with a little more and didn't take long after to track down. I repaired the wire first with black tape, but ended up replacing most of the wire. the nick in the casing let moisture get in and corroded the wire, was going to replace harness but it was just under $500 dollars for 16 inch harness.