We recently bought our 2014 JLG 600S with the Cat 3.4 engine. It will start fine initially but within an hour approximately it will shut itself off unexpectedly. When we go to restart it will crank over but will not fire. After waiting roughly 1-2 hours it will fire back up We checked.... Fuel cap off or on does not affect it Has good fuel flow from tank and through the pump which is working We tried replacing the ECM and did not change anything All wire and harness connections look good We had 2 mechanics look at it and check with diagnostic analyzer an no codes are shown If there is anyone who has experience with this issue please share your thoughts. Thank you in advance
Has anyone checked the fuel shutoff solenoid? Make sure it does not stop working after it heats up for awhile.
Thank you for your reply. Are these known to go bad on the 3.4 Cat Diesels? How can a person check if they are bad?
I'm not familiar with that engine, is it a common rail engine? If so that makes it alittle harder to diagnose. Which ECM did you replace? machine or engine. Maybe you could post some pidtures of the engine to give us a better idea of what it is.
This is the best I have at the moment. Thanks for your help I’ll take a couple tomorrow morning and post them Have a good night and Merry christmas
They aren’t actually a CAT engine They are a bastardized Fiat engine with CAT paint and an ECM that can be read by ET. They are hot garbage. I’d like to meet the engineers in a dark alley. The procedure for getting it out of derate after fixing emissions fault is the most retarded thing you will ever do as a mechanic.
Looking at dragon123's picture, it does not look like a common rail engine. It must be an earlier one. Would it still have an ECM if it was a mechanical engine?
Mechanically injected, but the ECU is just barely visable on the right side of the picture. Appears to be a Zexel VE injection pump and your FSS should be what that black w yellow striped wire is going to. I know with worn out Stanadyne DB rotory pumps, they'll heat up, get out of tolerence and won't restart until they cool down. You can confirm that by pouring room temp (not cold) water over them after they fail and they'll usually fire right back up. Don't know if the same procedure would work on that pump, but might be worth a shot. If you do that, make sure to fully cover that generator below it so no water gets into the windings. Post the serial of your machine and should be able to dig up more info.
The inj pump shut off solenoid is to the right of your pic. and the connection is laying on the steel lines going to the injectors..(white) U can either disconnect it and run a jumper from the + side of the battery to the spade in the connector.. idk if that’ll throw a code or not.. Or u can clip it straight to the solenoid stud.. If u want to bypass the solenoid entirely, unscrew it and remove the plunger and spring from the center of the solenoid and reinstall the body, unfortunately I don’t see a manual s/o lever on the pump.. which means you’ll have to choke off the fuel or open several steel lines going to the injectors..OR.. cut off the air with a clipboard.. Good luck..
I just swapped all the parts from a failed 3.4 cat to a long block. Both of them said Mitsubishi on them.