2003 Bobcat 763G fuel solenoid problem

[Jray]

2003 Bobcat 763G, problem started with fuel shut off would not shut when the key was turned off, then later the fuel solenoid would not open when trying to start engine. Replaced the fuel solenoid and still same problem. Checked and replaced fuses, replaced relays, inspected wiring and connectors, ect. I have 12 volts at fuel solenoid at pull terminal, ground is good, zero volts at hold terminal. I have the electrical schematics but still having trouble locating some of the numbered wires pertaining to the fuel solenoid. Any help and direction is much appreciated. Thanks

 

[Equipment_Tech]

I would start by confirming the wiring by using your wiring diagram for the fuel solenoid (Ground,Pull,Hold)

Bench test your new solenoid to ensure the wires (plug) on the machine side are activating the solenoid correctly

If everything checks out good and solenoid functions properly (12-volt battery bench test) referring to your wiring diagram perform a resistance test on the wires themselve starting from key switch to solenoid to confirm there is good signal throughout all the wires

Keep us posted

 

[Jray]

Thanks Equipment Tech for your response. Bench tested both solenoids (new one and the old one) both checked good. Installed new cab wiring harness, checked connector pins at right and left panels and connector to main harness. No hold function of fuel shutoff solenoid. UGGHHH. Should I pull the mainframe harness and relay/fuse panel and check the connections/wires? or work from controller back to the engine harness? Thanks again for any suggestions or guidance

 

[Robanybody]

There should also be a Bosch relay in that circuit. You'll find it under the cover between the bucket function levers, Right about where your calves are located.

 

[Jeffro]

Check the relay in fuse/relay panel between where your legs are while sitting in the seat. There is a fuse and relay for fuel. My S250 had bad corrosion in the box. A lot of cleaning and making sure terminals were tight when fuses and relays are in.

 

[Jray]

Will do, it will be my project for tonight when I get home. Several of the fuses were corroded, but not blown, so I replaced them all. Did you use a special cleaner on the relay plugs? I'm going to focus on that relay/fuse area and work my way back to controller. Thanks for your help

 

[Jeffro]

Will do, it will be my project for tonight when I get home. Several of the fuses were corroded, but not blown, so I replaced them all. Did you use a special cleaner on the relay plugs? I'm going to focus on that relay/fuse area and work my way back to controller. Thanks for your help

I used Qc electrical cleaner. Disconnect your battery before spraying it in there. It dries fast. Make sure terminals are tight to where the fuses and relay don't move easy.

 

[Equipment_Tech]

I would start by confirming the wiring by using your wiring diagram for the fuel solenoid (Ground,Pull,Hold)

Bench test your new solenoid to ensure the wires (plug) on the machine side are activating the solenoid correctly

If everything checks out good and solenoid functions properly (12-volt battery bench test) referring to your wiring diagram perform a resistance test on the wires themselve starting from key switch to solenoid to confirm there is good signal throughout all the wires

Keep us posted

Yes, I would check everything in that circuit to make sure. Hope you find the issue

 

[haymaker]

Will do, it will be my project for tonight when I get home. Several of the fuses were corroded, but not blown, so I replaced them all. Did you use a special cleaner on the relay plugs? I'm going to focus on that relay/fuse area and work my way back to controller. Thanks for your help

Any update so we know what it was??

 

[Jray]

I have cleaned fuse/relay connections, checked for loose wire connections on back of fuse/ relay box, bench tested engine harness, etc. The problem sill remains, turn key and pull function of fuel solenoid works but "hold" fails to hold fuel shutoff open, no 5 volts to 8800 wire at solenoid. Thinking of sending left panel to isoscell for evaluation, or controller evaluation

 

[haymaker]

Sorry if it comes to that. I hope someone has additional insight to the issue that may help.

 

[walio123]

The left panel has nothing to do with the fuel solenoid, the pull function comes from a relay in the fuse block and the hold function comes from the main controller. Check the integrity of the hold function cable to the controller and for a corroded pin in the controller socket. If the fault is in the controller...the problem is easily solved with an extra relay.....I can draw a schematic if you don't know how to do it. This is if the solenoid is working properly 100%

 

[Jray]

Will check connections of main harness to controller tonight and give update. Thanks for your help, you saved me from sending left panel off for repair. I will post findings. Thanks

 

[Jray]

Update !! Bought a new main wiring harness and installed. Still have the same problem with no hold function of fuel solenoid. Is my next step to replace controller? or send it to Isoscell for repair? I have spent a fortune on new parts and still having same original issue. Anyone used any other repair service for the controller? Thanks for any input

 

[walio123]

controller repair is expensive....just use simple car relay, and give + on hold wire after ignition - its very simple.

 

[Zanecr]

Update !! Bought a new main wiring harness and installed. Still have the same problem with no hold function of fuel solenoid. Is my next step to replace controller? or send it to Isoscell for repair? I have spent a fortune on new parts and still having same original issue. Anyone used any other repair service for the controller? Thanks for any input

Did you solve this?