Good afternoon all. I have a john deere 304j with the 3.0 deere diesel in it. The other day it starting idling up and down rear irratically like an old detroit. Its getting worse and now it surges when you try to drive it and has low power. Changed filters and checked for fuel restriction, but didn't help. Any Ideas??? Thank you:Banghead
Where are you located (Wisconsin?)? I bet it's pretty cold up there right about now. Have you used any diesel additive lately? IMO you are having a fuel related issue. If it's not the fuel jelling than I would start looking at the filters (which you said that you did). Check for loose fittings and injectors along the fuel lines. Be sure to go through the correct procedure for bleeding air from the fuel system. I would also check the fuel filters. If they are the cartridge type, like mine, be sure that they are seated correctly. Sometimes they can be a little tricky to get them right. Next would be the fuel pump. Is it mechanical or electric? Is there a lift pump? You may have already checked this, as you said that you checked for fuel restriction, but you did not say what you did to check. If your J model is similar to mine (544) than you should be able to check for fault codes in the dash. Have you? I still think fuel problem but electrical or ECM may be the next thing to check on. These are the things I would check out.
Check the lift pump...... my guess its going bad.
fuel spec I need to put in a guage at the lift pump. It sprays out of the line pretty quick when its cranking, which i know doesnt mean anything. I know it isnt a fuel gelling problem, i am not exactly sure how the fuel system is set up but, i know it is all under the valve cover.
Call your dealer to see about warranty, pips, and mods. There was one out for the Ctl's and skids with the same engine so there might be something there.
Finally drug the machine into the shop and hooked up a site glass and guage after the filter and i'm getting about 8 psi with the machine running. When it runs it surges about 1000 rpm up and down by itself. i wonder if there is a mechanical governor problem. it will not start in the warm without the the throttle being pushed a little
Called John deere and they said no warranty. Pulled valve cover and governor cover and found nothing obvious. I wonder if there is an injector screwing up causing the issue.
What you describe is not a injector problem. Sounds like a fuel supply or injection pump problem.
I have pressure after the lift pump. The dealership says its normal for the machine to hunt for an idle at first for a couple seconds. This one runs from 600 to 2000 rpm constantly if you can keep it running that long. It has a fuel system similar to a detroit except the outside body of the injector turns from what i can see
This loader has the 3.0 mechanical governed engine. Their should be no "hunting" by the governor. If you dont have a fuel problem then its a pump/governor issue.