Hi Guys, I have an old 96 3CX backhoe, that I bought for a project a while back. Try to fire it up every month or so to keep everything working. Currently won’t start due to electrical problem that I haven’t been able to find so far, it’s definatley not battery or bat terminals or fuses or relays, no dash light when key turned on. I’d like to Hotwire it to give it a quick run but mostly to move an old car that’s blocked in atm. I could prob get the motor to spin over directly from starter motor, but don’t know the makeup of how the fuel solenoid works. I figure there must be one seeing it turns off with key rather than pulling a manual know to stop. Anyone have an idea as to how I might tackle this? I live in a small town in NSW Australia and there’s no one local that can sort the prob directly for me. Prob have to eventually get it onto a truck to take to someone to fix, which would be damn near impossible with the loader bucket on the ground and backhoe bucket dug in on other end. Thanks in advance.
JCB 3cx help.
- Thread starter Ianrm
- Start date
diggerjones
Member
- Location
- South cheshire, audlem
I would ask on one of the jcb forums, there's lots of information on there
diggerjones
Member
- Location
- South cheshire, audlem
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- Location
- Glen Clova, Angus, DD8 4RD
What happens when you turn the key, to the accessory position and then to the start position?
In the accessory position warning lights should light up (charge and oil pressure) and a buzzer should sound. When you turn the key further, against a spring, the engine should crank.
In the accessory position a 12v feed goes to the fuel cutoff solenoid on the injection pump to open it. This can be easily bypassed with a fly lead from the battery if need be (preferably with a fuse in line). If the starter works then it can also be operated by applying a 12v feed to the relevant terminal on it.
In the accessory position warning lights should light up (charge and oil pressure) and a buzzer should sound. When you turn the key further, against a spring, the engine should crank.
In the accessory position a 12v feed goes to the fuel cutoff solenoid on the injection pump to open it. This can be easily bypassed with a fly lead from the battery if need be (preferably with a fuse in line). If the starter works then it can also be operated by applying a 12v feed to the relevant terminal on it.
Have you access to a multimeter or circuit tester?
Are you getting battery power at both sides of the 3 amp ignition fuse in the fuse box to the right of the seat and power out of the 50 amp main fuse in the box connected to the positive battery terminal? You need to check for power at the back of the key switch too.
Are you getting battery power at both sides of the 3 amp ignition fuse in the fuse box to the right of the seat and power out of the 50 amp main fuse in the box connected to the positive battery terminal? You need to check for power at the back of the key switch too.
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Oops, I thought that’s what I did, can you give me a link to a good one or two, plz. Thx
Yep, been trying to get to the ignition switch. Might have more luck after I remove the cable going to heater switch. I’ve got a bit of a history of breaking stuff by pulling on stuff with one hand when you need two. Lost my dominate arm a few years back, but still try to do most things. Has given me a few ideas tho. Might be tricky getting to starter if I go the Hotwire route. Would usually lift the loader bucket right up to clear space at side, but not without motor. Hopefully I can find the real prob first. Cheers
Yes, have mm and test light, replaced a few of the solenoids that I thought might be involved, with newbies. Even bought a relay tester ( rather than making one) and had time for it to come from China while pondering on next step. Checked for blown fuses with test light. Will have to try and fathom the wiring diagram to work out which fuses should be powered with ignition on. Only about 25% had power with ignition on. Figured maybe the rest were only powered when alternator running and/ an accessory was on
Zebbedee
Member
- Location
- Scotland in the best bit
Start at ignition switch if there’s power there make sure switch is actually working but I would guess that there is a supply issue to switch eg a wire has come off
Good to hear my theory confirmed. Will check out a couple other things suggested first. Main priority is not making things worse my tearing out the dash and fu*king up more sh!t. There are 2 screw connectors with a heap of wires in each feeding the dash near the heater switch, will try and avoid disturbing them if I can.
startinghandle
Member
this may sound silly but have you checked battery is good and have you checked earth connection on chassis?
I found out a long time ago to check easy things first
I found out a long time ago to check easy things first
- Location
- Glen Clova, Angus, DD8 4RD
Earths are often overlooked....
Many poor starting problems are down to under 9V at the starter!
Yep charged battery, also hooked up second battery with jumper leads. Radio, 2 way and lights work ok, but no dash lights or buzzer when ignition on. It’s going to be tricky getting to anything on motor with the loader bucket down and the boom in the way. Will try and get dash out without breaking any of the big bunch of brittle old wires and work my way back from there I think.
startinghandle
Member
Trying tapping around dash with piece of wood and try to start at same time
Something else I found out a longtime ago
Something else I found out a longtime ago
- Location
- Glen Clova, Angus, DD8 4RD
Could be a fault in the main feed to the keyswitch. The lights bypass this. The radio might too.
I'd be rigging a flylead from battery positive to the pump stop solenoid to hold it open and use another to the starter motor start terminal to crank her. Has she still got engine side covers? (Very few still have ime). If not there is just room to get to the starter with the loader down.
Once she's running lift the loader and prop it. You'll have access to do a proper fault trace then.
I'd be rigging a flylead from battery positive to the pump stop solenoid to hold it open and use another to the starter motor start terminal to crank her. Has she still got engine side covers? (Very few still have ime). If not there is just room to get to the starter with the loader down.
Once she's running lift the loader and prop it. You'll have access to do a proper fault trace then.
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