Help please Fuse popping

[Smiffy]

Firstly those little 8014 will start absolutely on the key all the time the battery is good and the slightest decline they don't even turn over
Secondly I think all jcbs of that age should have a basic imoboliser with a chipped key.
They really aren't very complicated machines. Even with the imoboliser

 

[Deanofire]

Firstly those little 8014 will start absolutely on the key all the time the battery is good and the slightest decline they don't even turn over
Secondly I think all jcbs of that age should have a basic imoboliser with a chipped key.
They really aren't very complicated machines. Even with the imoboliser

so are you saying you think the battery could be causing the 40A fuse to keep blowing ?

 

[V8Druid]

so are you saying you think the battery could be causing the 40A fuse to keep blowing ?

you really need a tip top battery for any diesel engine ...
if it 'labours' at all it will struggle to start, as a compression ignition (diesel) engine needs to be spun over at optimum speed, in order to ignite the fuel charge ...
slowly 'squashing' the cylinder's contents will not result in ignition - it needs rapid compression .

low voltage in batteries also causes all manner of other issues and particularly in any electronics on board ... they need a specific voltage to function and a poor battery's voltage will dip massively and rapidly with a heavy draw, like heater plugs or starter ... the initial heater plug draw on a poor condition battery can/will drop the available power to the starter, post heat cycle

 

[Steve]

It is unlikely the battery is causing the fuse to blow . The fuse is more likely to blow because of a dead short. A dead short will also pull the battery down.

 

[craig]

Try disconnecting the heater plugs, and try again to see if its blows, it could be a plug failed and shorting out.
Alternatively replace the fuses with some thing solid, screw driver, spanner, pliers etc, and try again, look to see what smokes , that will be where the fault is



*second paragraph is a joke/not recommended/do not try*

 

[Rob65]

I had a glow plug fail by becoming a short circuit to the head of the engine.

I suggest disconnecting the wire from the heater plugs and replacing the 40 amp fuse again.
If it is a heater plug problem the engine will turn over using the key but probably won’t start. Everything else should work at this point.

If it looks like heater plugs are a problem you can identify which one it is by taking all the connections off between them and then checking the resistance of each plug with a multi meter from the connection on the top to a good clean point on the engine. I can’t remember the exact figure but it will measure something like 5 ohms for a good plug.

If you are ok with the first bit of what I have described but don’t have a multimeter then changing all the heater plugs would be my advise.

 

[Smiffy]

so are you saying you think the battery could be causing the 40A fuse to keep blowing ?

No quite the opposite. You wouldn't have got the odd start out of it if the battery is a problem thats it nothing atall without a jump start. However as said if it's on the original battery it will do you absolutely no harm to replace it. Especially if it's slow turning over.


Do you have a multi meter?? I can't remember if you said in your original post. This will speed up diagnosis as you can check for continuity rather than unplug things

 

[Steve]

As the 40 amp fuse is blowing with the key only turned to the first position the problem is likely to be a dead short with something that only comes live with the ignition on like ignition wiring electric fuel pump & associated wiring, also worth checking wiring to the arm rest safety switch as they could easily get trapped & short out.

 

[Furniss]

IIRC Mine did it and it was heater plugs .... take the wire off the rail connecting the plugs and try again.

 

[Gecko]

so are you saying you think the battery could be causing the 40A fuse to keep blowing ?

The manual I have downloaded (Sn. 1156000 +) shows the primary fuse as 80A, so I'm assuming this manual doesn't cover your machine too closely.

Typically, glow plugs suck 5~10A each and often spec'd at 11V (not 12V).
If it's 10A, then each plug will measure 1.1 Ohms.
With four glow plugs connected together, it'll look like 0.27 Ohms which is about the same as the test leads on a multimeter.
Trouble is, most meters can't read accurately enough at the bottom of their range to give you confidence in the reading.
eg. cheap leads and a shorted plug may give the same reading as good leads and a good plug.
Just some Gotchas to be aware of.

 

[Deanofire]

you really need a tip top battery for any diesel engine ...
if it 'labours' at all it will struggle to start, as a compression ignition (diesel) engine needs to be spun over at optimum speed, in order to ignite the fuel charge ...
slowly 'squashing' the cylinder's contents will not result in ignition - it needs rapid compression .

low voltage in batteries also causes all manner of other issues and particularly in any electronics on board ... they need a specific voltage to function and a poor battery's voltage will dip massively and rapidly with a heavy draw, like heater plugs or starter ... the initial heater plug draw on a poor condition battery can/will drop the available power to the starter, post heat cycle

Thanks for this explanation i am going to order a new battery today and go from there.

 

[Deanofire]

I had a glow plug fail by becoming a short circuit to the head of the engine.

I suggest disconnecting the wire from the heater plugs and replacing the 40 amp fuse again.
If it is a heater plug problem the engine will turn over using the key but probably won’t start. Everything else should work at this point.

If it looks like heater plugs are a problem you can identify which one it is by taking all the connections off between them and then checking the resistance of each plug with a multi meter from the connection on the top to a good clean point on the engine. I can’t remember the exact figure but it will measure something like 5 ohms for a good plug.

If you are ok with the first bit of what I have described but don’t have a multimeter then changing all the heater plugs would be my advise.

Thanks i will try this today if i can work out how to disconnect the plugs,

 

[Deanofire]

No quite the opposite. You wouldn't have got the odd start out of it if the battery is a problem thats it nothing atall without a jump start. However as said if it's on the original battery it will do you absolutely no harm to replace it. Especially if it's slow turning over.


Do you have a multi meter?? I can't remember if you said in your original post. This will speed up diagnosis as you can check for continuity rather than unplug things

Thanks yes i do have a meter but not 100% sure what i am testing.

 

[Deanofire]

As the 40 amp fuse is blowing with the key only turned to the first position the problem is likely to be a dead short with something that only comes live with the ignition on like ignition wiring electric fuel pump & associated wiring, also worth checking wiring to the arm rest safety switch as they could easily get trapped & short out.

That was my first thought and i did look under the arm ,and as i said there were two yellow wires cut but they only lead to an empty plug for accessories i suppose so i taped them up. not sure how the arm safety switch works as i cant see a physical switch.

 

[Deanofire]

IIRC Mine did it and it was heater plugs .... take the wire off the rail connecting the plugs and try again.

am trying this first today
Thanks

 

[Deanofire]

The manual I have downloaded (Sn. 1156000 +) shows the primary fuse as 80A, so I'm assuming this manual doesn't cover your machine too closely.

Typically, glow plugs suck 5~10A each and often spec'd at 11V (not 12V).
If it's 10A, then each plug will measure 1.1 Ohms.
With four glow plugs connected together, it'll look like 0.27 Ohms which is about the same as the test leads on a multimeter.
Trouble is, most meters can't read accurately enough at the bottom of their range to give you confidence in the reading.
eg. cheap leads and a shorted plug may give the same reading as good leads and a good plug.
Just some Gotchas to be aware of.

ok thanks seeing as i am not great with ohms on a test meter i will try as suggested disconnecting the rail to glow plugs and try turning over to see if it blows the fuse.

 

[Gecko]

Thanks yes i do have a meter but not 100% sure what i am testing.

If you take the bus-bar off, you can measure the resistance from the top terminal to the engine block.
The plugs should be in the 1~2 Ohm range and all read the same.

If your meter has manual range settings, set it to the lowest Ohm range.

 

[Deanofire]

If you take the bus-bar off, you can measure the resistance from the top terminal to the engine block.
The plugs should be in the 1~2 Ohm range and all read the same.

If your meter has manual range settings, set it to the lowest Ohm range.

am going to go and look at it now will take some pictures lol

 

[Deanofire]

If you take the bus-bar off, you can measure the resistance from the top terminal to the engine block.
The plugs should be in the 1~2 Ohm range and all read the same.

If your meter has manual range settings, set it to the lowest Ohm range.

right have looked at it and think i found the bus bar, if its the flat rail at the top i can get to the forst nut maybe possibly the second but no chance the furthest one as its right at the back, and i think thats where the wire is connected as well so no chance removing that either.
sorry its so dusty in there but here in the south of France , everything outside gets covered in this dust
am not sure what the big plug at the front is

 

[Deanofire]

Quick question does the cab on these tilt to gain access to the engine , if so, how ?
TIA