Newbie question - 05 John Deere 4520 Misfiring

[GM9]

Hello. I am new to the forum. I searched and can't seem to find an answer. (Not sure how to search for an 05 4520. Is it 4520, 4X20, 4xxx, 4000 series, etc? Then there is the 70's vintage 4520)

Anyway, I've owned a 2005 4520 for a few years now. For the past while, it misfires when accelerating. Like one or two cylenders not firing. It seems to be getting worse, almost to the point of shutting off. A freind mentioned something about his Kubota having air in the fuel lines(?). Does that make sense? Any help will be appreciated.

 

[GM9]

Oh yeah, in addition, I am getting an intermittent error code 74, but not sure that is relavent.

 

[RoyJackson]

Can't help you with the error code, but it sounds like you have at least one bad injector.

 

[AKfish]

You should have a listing for a number of the more common error codes in the back of your Owner's Manual. Does sound like a bad injector or two. Have you noticed any change in the crankcase oil? Like over full? Or excessively black - pretty quickly after an oil/filter change? Any diesel fuel smell to the oil?

Injectors that are sticking will tend to load up the engine crankcase with unburned fuel.. That's not a positive situation!

AKfish

 

[arlen4720]

According to my service manual ERR_74 is the display mode switch is stuck on....Doesn't sound related to your problem, but you never know..

 

[Ken]

Do you have access to a thermos temp gun? if so measure the exhaust temp manifold . the cyl. (cyls) causing the misfiring can lead you toward problem
Next is it a single cyl or more than one,
constant or random maybe check for fuel sys problem injector or pump.
This also could be head gasket failure. so check compression. low cyl valve or ring .

What does the turbo sound like when this is happening . squealing or loss of pressure.

Wish could help more just need more information.
ken