John Deere 990 fuel problem

Markbasinger · Sep 9, 2022

John Deere 990 ran out of diesel fuel. Coasted off a bank and tried to restart. Cranked briefly then refilled with fuel. Started but had to bleed. Ran rough and discovered 1st cylinder closest to dash is not firing. All other cylinders are firing good. Removed and cleaned injector for that cylinder. No change. Replaced that injector but no change. Any ideas? Any help appreciated.

thepumpguysc · Sep 9, 2022

Did u leave the line off to see if the pump is actually pumping fuel TO that injector.??
U could bend the line SLIGHTLY and hook an injector back up to the line TO SEE if it’s popping the injector..
B VERY CAREFUL WHEN DOING THIS.. the spray from the injector WILL penetrate your skin and you’ll end up in the hospital.!!
It’s either not enough fuel FROM THE PUMP..
A faulty injector..
Or a dead cylinder in the engine.. a compression test can verify THAT..

Markbasinger · Sep 11, 2022

thepumpguysc said:
Did u leave the line off to see if the pump is actually pumping fuel TO that injector.??
U could bend the line SLIGHTLY and hook an injector back up to the line TO SEE if it’s popping the injector..
B VERY CAREFUL WHEN DOING THIS.. the spray from the injector WILL penetrate your skin and you’ll end up in the hospital.!!
It’s either not enough fuel FROM THE PUMP..
A faulty injector..
Or a dead cylinder in the engine.. a compression test can verify THAT..

Thanks for the suggestions. I loosened the line to the top of the injector of the non-firing cylinder and while there is fuel there, I don’t know if it is enough volume or pressure . I replaced the injector for that cylinder but it still didn’t fire. I did not yet try testing to see if the injector actually fires. Thanks for the safety tip. I’ll keep you posted.

Markbasinger · Sep 19, 2022

Tested the injector as you suggested and it functioned properly. I then went through each fuel hose and connection. There were 2 hoses with small cracks in the back where I could not easily see them. I also had one nut on the top of the pump that was not completely tight. Once hoses replaced and all lines tightened. it worked. It's often the simple things isn't it?? Thanks so much for your help!