JCB 3cx help.

[Daveh]

You could try taking out the 4 screws and having a look behind the panel where the ignition sits to see if the feed wire has fallen off, it happened once on mine.
Wouldn't be a bad idea anyway to see if you've got power there in case the switch is faulty.

 

[gatepost]

replaced my ignition switch, as that was faulty, she would start but as soon as you moved the shuttle it cut out, but it was the switch!

 

[holwellcourtfarm]

This is a project 7 "Grey Cab" wiring diagram but most will be the same:

If you can get a 12V feed to A (fuel solenoid) and B (starter terminal) she'll start.

2 is the keyswitch

 

[Ianrm]

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.

Yes, both side covers off. That would certainly make things a lot easier, thanks

 

[Ianrm]

This is a project 7 "Grey Cab" wiring diagram but most will be the same:

View attachment 959925

If you can get a 12V feed to A (fuel solenoid) and B (starter terminal) she'll start.

2 is the keyswitch

Thanks mate

 

[Ianrm]

O

Thanks mate

Ok, did some investigating, there are 2 relays marked as ignition in position 1 & 4. ( been searching for owner manual for a month, found it today) there is power in to both relay sockets at all times. No output ( solenoid not activated with key on) Figure i will run a jumper cable from battery with a couple of hefty wires connecting via a fuse on each ( start with 5a and work my way up) going to where out put is on fuse mounting blocks. This might confirm possibility of ignition switch fault. Either that or I’ll let the magic smoke out. If anyone thinks this is a real bad idea, I’d like to know. Won’t do it till tomorrow, as it’s part beer o’clock now. Thanks for your time fellas

 

[Zebbedee]

Just check for power at key switch ?? Work logically?

 

[Ianrm]

Just check for power at key switch ?? Work logically?

It’s tricky to get dash out. Want a lead before going that route. Am retired, live Stuarts Point NSW, Australia.

 

[Ianrm]

It’s tricky to get dash out. Want a lead before going that route. Am retired, live Stuarts Point NSW, Australia.

I was a plant operator. My son does contract harvesting and spraying, has a John Deere 640D harvester and a JD 4630 sprayer

 

[Ianrm]

On reflection, if my theory doesn’t pan out, the next step will be checking what’s going in and out of ignition switch anyway, same if it does. Should prob work out how to pull the dash with one hand without destroying anything first, to check ign switch first.

 

[holwellcourtfarm]

On reflection, if my theory doesn’t pan out, the next step will be checking what’s going in and out of ignition switch anyway, same if it does. Should prob work out how to pull the dash with one hand without destroying anything first, to check ign switch first.

The biggest problem on that model is the rev counter cable. From project 7 onwards they have an electric rev counter.

 

[Ianrm]

The biggest problem on that model is the rev counter cable. From project 7 onwards they have an electric rev counter.

What year did the project 7 models start?

 

[agrimax]

Project 7 models or grey cabs started in 1987. Or at least they did with us in the UK,and they ran til August 91. If yours is 96,I'd make it a Project 8. Dashboard to the right hand side of the seat...

 

[holwellcourtfarm]

Who had the great idea to put a coal fire power station in the middle of London, out of curiosity???

What year did the project 7 models start?

Project 7 models or grey cabs started in 1987. Or at least they did with us in the UK,and they ran til August 91. If yours is 96,I'd make it a Project 8. Dashboard to the right hand side of the seat...

Sorry folks, I've now realised my mistake in thinking I'd read the op as an '86 not a '96 3CX.

My replies will have been wrong as there are big differences once you move to the project 8.

Apologies.

 

[Ianrm]

Project 7 models or grey cabs started in 1987. Or at least they did with us in the UK,and they ran til August 91. If yours is 96,I'd make it a Project 8. Dashboard to the right hand side of the seat...

Y

Sorry folks, I've now realised my mistake in thinking I'd read the op as an '86 not a '96 3CX.

My replies will have been wrong as there are big differences once you move to the project 8.

Apologies.

no worries mate, wasn’t looking forward to battle with tachometer cable, the heater control cable is enough of a pain when trying to get the dash out.

 

[Ianrm]

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.

Ok, no power to ignition switch, haven’t found the 50a fuse near + battery terminal yet. If that was blown would I still have radio and lights ( Which are both working)?

 

[Zebbedee]

Ok, no power to ignition switch, haven’t found the 50a fuse near + battery terminal yet. If that was blown would I still have radio and lights ( Which are both working)?

Would ignition supply not come from starter? Main battery lead goes to starter then supply lead to ignition comes from there I would think, but just put a jumper supply from battery to ignition switch and see if the machine will start for you

 

[Ianrm]

Would ignition supply not come from starter? Main battery lead goes to starter then supply lead to ignition comes from there I would think, but just put a jumper supply from battery to ignition switch and see if the machine will start for you

I’ll have to work out which wire going to switch is supply wire. There are 4 thick wires, one thicker than the other 3. There is continuity ( when plugged into switch) between the thickest wire and one of the other thick wires, also. between the other 2 thick wires. Also 3 thinner wires plugging into switch. My best bet is to put power to the thickest wire via a fuse, worse case scenario I blow the fuse, or make sone smoke I guess. If I can fire the old girl up, I can lift the bucket and try and find that 50a fuse.

 

[Netherfield]

Are there no numbers or identification on the switch? Is it a lucas type switch, mine was older model than yours which did, No1 was the main input and usually brown.

One of the thicker wires must be input, one for the starter solenoid, one for the heater plug.

 

[Zebbedee]

I’ll have to work out which wire going to switch is supply wire. There are 4 thick wires, one thicker than the other 3. There is continuity ( when plugged into switch) between the thickest wire and one of the other thick wires, also. between the other 2 thick wires. Also 3 thinner wires plugging into switch. My best bet is to put power to the thickest wire via a fuse, worse case scenario I blow the fuse, or make sone smoke I guess. If I can fire the old girl up, I can lift the bucket and try and find that 50a fuse.

You should be able to work it out by Checking continuity on switch