Starting problem - smoke form bonnet

[piers_finlayson]

Tried to start the truck up this morning, after having already driven for a while, and was greeted by no starter motor engaging, and smoke rising from under the passenger side of the bonnet - probably just behind the battery.

I was in a bit of a rush and had to leave the truck, but will be able to go and check it out a bit tomorrow - any suggestions as to what I'm looking for - blown fuse/relay - or is this likely to be something more serious?

Thanks,
Piers

 

[nlbyrne]

The 24volt change over is behind the battery, sounds as if something is fried

 

[karl webster]

As mentioned 24v starter sol or bad connection on a bat terminal maybe

karl

 

[frank rabbets]

My relay is under the DRIVERS side battery. Same side as the heater. I suspect they are all the same.

Frank

 

[Towpack]

My relay is under the DRIVERS side battery. Same side as the heater. I suspect they are all the same.

Frank

That'll be the intake heater relay, not the 12/24v changeover. Piers LC won't have one of these being a 12valve model.

 

[frank rabbets]

Quite correct! Got muddled again. Smoke often means heater relay. I'll have to read more carefully.

Frank

 

[Chas]

When smoke came from under my bonnet it was because the engine had started but the starter motor had stuck in and the engine was driving the starter.

 

[Chris]

Smoke - from under bonnet?

That brings back memories!

Brrrrrrrr Let's no go there.

Chris

 

[piers_finlayson]

Smoke - from under bonnet?

That brings back memories!

Brrrrrrrr Let's no go there.

Chris

Yes, I was quite glad when the smoke stopped

Heater relay doesn't sound vital. How come it now doesn't turn over? Likely fuse blown?

Piers

 

[Scott]

Do you still have continuity between the engine and the negative terminal on the battery? I've had it before on a few different vehicles where the earth strap has broken and the symptoms are that the vehicle will not turn over, the current will try and find its way back to the battery via other wiring or cables (sometimes the handbrake), causing the new pathway that the current has found, to over heat and smoke/burn out pretty quickly.

It's only a suggestion. If you do find that you've lost the earth connection between the engine and the battery, you can substitute the earth strap (for testing purposes only) with a jump lead. Connect the jump lead to a good clean metal part of the engine, and then to the battery negative terminal, this will then take place of the failed earth strap and complete the starter circuit. You can then try and start the vehicle.

On the off chance that this is the cause, the wires that have been overheated/smoking due to the overload of trying to take the full force of the starter current, need to be identified and repaired/replaced.

Good luck either way.

 

[piers_finlayson]

No satisfactory conclusion to this thread yet.

I was unable to spend any time looking at the truck over the weekend, and had to get it shifted before the week as it was parked in a 45 minute parking bay . I therefore had to arrange to get the trucked towed to my local garage so they could fix it.

When they showed up they got it started fine, took it back to their garage, checked all the wiring, etc and couldn't find anything wrong, signs of burning, etc.

So, this is worrying. I'm going to try and find some time this w/e to look myself, but I'm not terribly experienced at this kind of thing, so would appreciate any suggestions. Sounds like at the very least I should be trying to take out the passenger battery and checking around there - given that's where the smoke was coming from.

 

[piers_finlayson]

Finally got around to looking at this myself and I thought I'd conclude this thread.

Looks like the -ve cable from the passenger side battery had come loose (the bolt clamping it together had snapped) and had shaken almost free. Then when I started the truck next time and it pulled power from that battery it arced and melted some of the battery terminal due to the bad connection (hence the smoke, and then total lack of connection preventing me from starting) - found small bits of metal that were once liquid on top of the battery and a bit missing from the terminal.