1. Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

JLG 45ic Electrical Problems

Discussion in 'Other Construction/Demolition Equipment' started by Buck2010, Aug 30, 2010.

  1. Buck2010

    Buck2010 Member

    Joined:
    Aug 30, 2010
    Messages:
    11
    Location:
    Alabama
    My JLG lift is not supplying fuel when i turn the key to the on position. I applied 12v to the fuel pump and it works, checked the fuel shut-off solenoid with 9v and the plunger moves. Could this be a bad relay somewhere? Any help would be appreciated.
     
  2. tool_king

    tool_king Senior Member

    Joined:
    Mar 29, 2010
    Messages:
    1,173
    Occupation:
    road mechanic owner
    Location:
    new jersey
    what kind of lift is this boom or scissor ? what is the serial number? what kind of engine is this lift?that why i can look it up in manauals.
     
  3. willie59

    willie59 Super Moderator

    Joined:
    Dec 21, 2008
    Messages:
    11,906
    Occupation:
    Service Manager
    Location:
    Knoxville TN
    It's an articulated boom lift tool king, they were available in electric, Yanmar diesel, or Vangaurd dual fuel engine. If it's a dual fuel, make sure someone hasn't (for whatever reason) flipped the select switch for gas/propane to where it's not in the gasoline position, I've seen it happen many times. If that's not it, you need to go to JLG website and download the wiring schematic. It's fairly simple, and a decent diagram. The power goes through the fuel relay, the fuel select switch, then to a final fuel relay. But that last fuel relay gets it's ground via the engine processor, not sure how it's doing that. Also, there will be no power on wire going to final fuel relay unless your cranking engine, then it will power up that circuit. Once engine starts and has oil pressure, an oil pressure switch changes first fuel relay and sends ignition power to the fuel circuit, there's no power on fuel pump wire with ignition switch just in "ON" position.
     
  4. Buck2010

    Buck2010 Member

    Joined:
    Aug 30, 2010
    Messages:
    11
    Location:
    Alabama
    Thanks for the information, I have checked the dual fuel switch and it is in the gas mode, but now that you say that it has me wondering if something has malfunctioned with that switch (because i have flipped it a time or two). I thought the pump would have power to it with the key in the on position, should the fuel shut off solenoid have power to it when the key is on? And I am assuming when power is applied to that solenoid it is letting fuel into the carb? I will do like you say and download the schematic and start there. Also, does the engine tray pivot out? I saw some swing arms in the parts manual and there is a 3/4 inch bolt on the exhaust side of the tray, i removed it and then there is a smaller bolt on the radiator side, but it doesn't act like it wants swing out. Thanks, again for the help..
     
  5. willie59

    willie59 Super Moderator

    Joined:
    Dec 21, 2008
    Messages:
    11,906
    Occupation:
    Service Manager
    Location:
    Knoxville TN
    Go to www.jlg.com

    In the left column, click on Services

    In the left colun, click on Parts and Service Manuals

    Select JLG

    Select JLG boom lifts

    Then select 40 45IC

    The schematics are in both the parts and service manuals, download both.
     
  6. willie59

    willie59 Super Moderator

    Joined:
    Dec 21, 2008
    Messages:
    11,906
    Occupation:
    Service Manager
    Location:
    Knoxville TN
    The little solenoid on the carburetor is called an "anti-dieseling solenoid". When you take power away from that solenoid, it sticks a plunger into the main jet of the carb and stop fuel flowing through carb, kills the engine. As for the fuel pump circuit, I'll try and walk you through it.

    Ignition power comes from 87A of ignition relay, white/yellow wire. This relay is powered up by the platform and lower ingnition on switches. The white/yellow wire powers a number of circuits, including ingnition. It goes to terminal 87A of first fuel relay. You see this relay just above the Auto Choke Sol on the schematic. Notice, just before white/yel connects to 87A of fuel relay, it splits off and sends power to other circuits, one being the coil for the fuel relay. Power goes through the coil, and is looking for ground to activate the coil via the gray/blu wire. The gray/blu ties into the Engine Low Oil Pressure switch circuit, and finds ground because that switch is now closed because there's no oil pressure. Thus, the coil in fuel relay powers up and pulls the contact off of the ignition circuit on 87A and connects the contact with term 87 of fuel relay, the starting circuit. Therefore, when you turn the ignition "On", it takes away power from the fuel pump circuit. Once you hit the starter button, then you get power for the fuel pump from the start circuit via the contact connection in the fuel relay. Once engine gets running, and the low oil pressure switch breaks open, then the coil in fuel relay releases the contact and connects to 87A once again, sending power to fuel pump via ignition circuit.
     
  7. Buck2010

    Buck2010 Member

    Joined:
    Aug 30, 2010
    Messages:
    11
    Location:
    Alabama
    Thanks ATCO, prior to my problems in getting the lift to crank i had a bad coil on cylinder 2, I replaced that coil with a new one. I started it after i replaced it and thought ok that worked fine. It ran good then it shut off kind of sudden, i thought it had run out of fuel. Now after reading your post above, i think you just solved my problem, I will go back and check my coil install. Evidently, I have mechanic skillz they are just all bad skillz :)
    Hopefully this is the problem, i will check it tomorrow. Thanks.
     
  8. Buck2010

    Buck2010 Member

    Joined:
    Aug 30, 2010
    Messages:
    11
    Location:
    Alabama
    I checked the new coil i installed and everything looks correct. I pulled the fuel line off of the pump and now it is not trying to pump gas when i turn the engine over. It was pumping gas earlier, should i replace the 87A fuel relay(s)?
     
  9. willie59

    willie59 Super Moderator

    Joined:
    Dec 21, 2008
    Messages:
    11,906
    Occupation:
    Service Manager
    Location:
    Knoxville TN
    No need to replace parts/relays yet because you haven't deterimined if one is bad. Get out your 12V test lamp and start testing the fuel pump circuit while having a helper crank engine. You could start at the fuel pump and work your way back. You need to locate that relay that's shown in the schematic in area of fuel pump.

    Have helper crank engine and see if wht/yel wire on terminal 30 of relay is hot. If not, use the schematic to start working your way back the circuit while testing.

    If wht/yel on term 30 is hot when cranking, see if wht/yel on term 87 is hot when cranking. If it's not, remove blk/wht wire from term 86 on relay, put a jumper wire on 86 and connect it to ground.

    If this doesn't allow power from 30 to go to 87 when cranking, failed relay.

    If it does allow power to go from 30 to 87, something faulty with ignition processor.
     
  10. Buck2010

    Buck2010 Member

    Joined:
    Aug 30, 2010
    Messages:
    11
    Location:
    Alabama
    I found the fuel pump relay, 30 was hot while cranking, 87 wasn't hot while cranking, I jumped 87 to 30 and it crank and ran fine. I couldn't figure out how to pull 86 out of the harness easily so i didn't ground 86, do I need to or can I assume this is a bad relay?
     
  11. willie59

    willie59 Super Moderator

    Joined:
    Dec 21, 2008
    Messages:
    11,906
    Occupation:
    Service Manager
    Location:
    Knoxville TN
    Ok, now your saying you are working with the fuel relay that is the last electrical control to fuel pump? If so, I think I understand what your saying that you couldn't remove ground wire (blk/wht) on relay terminal 86, it's probably one of those sealed modular relay housings that require a tool to remove terminals from housing. Really no need to replace the relay at this point. If you had power on wht/yel on relay terminal 30, but it didn't power up terminal 87, you really need to test blk/wht on terminal 86, even if you have to cut the wire, and put a jumper on it to ground. If you do that, and the relay now operates the fuel pump, the problem is the ignition processor isn't making a ground for the fuel relay. I'm not sure why they are using the processor to make a ground for the relay, I'm sure they have some reason, but I'm thinking you'd be ok simply wiring the blk/wht wire to a good ground and leave it that way.
     
  12. Buck2010

    Buck2010 Member

    Joined:
    Aug 30, 2010
    Messages:
    11
    Location:
    Alabama
    Yes, the relay looked like it was sealed, I will cut the black/white wire 86 and ground it. I found the start relay lying in the engine tray, it looked like the metal clip that holds the relay to the relay bracket has been broken off for some time. Do you think the relay gets ground from that clip that mounts it to the bracket? I didn't try holding that relay up against the bracket and try starting it.
     
  13. willie59

    willie59 Super Moderator

    Joined:
    Dec 21, 2008
    Messages:
    11,906
    Occupation:
    Service Manager
    Location:
    Knoxville TN
    Nope, look at your wiring diagram. The relay sends power to terminal 30, that same wire jumps off and sends power to terminal 85, which is for the coil of the relay. Now the relay only needs a ground on terminal 86 to activate relay. That would be blk/wht wire on terminal 86. That's the way all these type relays work. Terminals 85 and 86 are for the relay coil. Terminal 30 is the common terminal for the relay contacts, terminal 87 is NO (normally open) to terminal 30, terminal 87A in NC (normally closed) to 30. "Normally" in any electrical circuit is always used to describe a circuit in it's "off" position, no power to it, no power activating anything, basically a unit that is stopped.
     
  14. Buck2010

    Buck2010 Member

    Joined:
    Aug 30, 2010
    Messages:
    11
    Location:
    Alabama
    I cut the blk/white wire 86 and grounded it to the relay bracket, still wouldn't start. When I jump 87 and 30 it starts up. Does that mean relay or ignition processor? I managed to get the relay apart and exposed the relay coil, which was a job in itself. I am going to go back through some of your previous post and see if i can wire the relay up to 12v and see if i can activate the relay, I am going blind trying to read that schematic.
     
  15. willie59

    willie59 Super Moderator

    Joined:
    Dec 21, 2008
    Messages:
    11,906
    Occupation:
    Service Manager
    Location:
    Knoxville TN

    Whoa, slow down bro, ain't no big deal, your doing Ok. If you grounded terminal 86 of relay and it still didn't respond, that simply means relay is probably bad. Try a new relay. Point is, if you have power on terminal 85 of relay (while cranking), and a good ground on terminal 86 of relay, that should activate relay and connect terminal 30 to terminal 87 of relay and power up your fuel pump.
     
  16. Buck2010

    Buck2010 Member

    Joined:
    Aug 30, 2010
    Messages:
    11
    Location:
    Alabama
    Ok will do.
    The schematic has two numbers for that relay 848/849, I am guessing I need the 849 (#4460375). I have sent an email to www.epwparts.com to see if they have that part. They are not showing that part on their site. Thanks for the help.
     
  17. willie59

    willie59 Super Moderator

    Joined:
    Dec 21, 2008
    Messages:
    11,906
    Occupation:
    Service Manager
    Location:
    Knoxville TN
  18. want 2 get high

    want 2 get high Member

    Joined:
    Aug 14, 2018
    Messages:
    12
    Location:
    IL
    I know this is an old thread but I had the same problem with my 45IC. Swapped out the relay with one I pulled out of a truck at the salvage yard and back in business.
    Hope you had the same out come.