Starting problem

[Hawklord]

My 1994 300TDI defender has had a starting problem on and off for the past 6 years and has just occurred again after being no problem for over a year. When the key is turned all lights etc come on but at the last position there is absolutely nothing, no clicks can be heard from relays or solenoids and no turning of the starter motor. To fix the problem I have to wriggle the big cable that runs from the under bonnet fuse box to the starter motor and eventually it will start and may be fine for days, months or years. 3 years ago I removed the under bonnet fuse box and cleaned al the connectors and it was fine for about a year but didn't "fix" the problem. My thoughts are that the issue is in the fuse box but as these cost about £100 I would like to be certain that this is true. As there is no audible click could the starter relay possibly be faulty and by wriggling the positive starter cable I am somehow making the relay work again ?

Can anyone suggest possible causes as it can become quite stressful every time I turn the key not knowing whether or not it is going to start.

 

 

[Snagger]

The wires have probably come off the back of the ignition switch.

[Hawklord]

If that was the case then how does it eventually start by wriggling the live feed wire from starter motor to the under bonnet fuse box which is the other side of the vehicle.

[steve b]

I would start with removing that HD fuse box to check the connections closely and also that wire too . Remove Battery earth first .

I'm not too far from you so if you get stuck....

cheers

Steve b

[Giles]

Never fun is it? I'd try - maybe you have - removing, cleaning and resecuring the battery connections and the main earth to block connections (side of gearbox?? another one???). Just a thought

 

[Snagger]

I misunderstood which wire you were moving.  In that case, it’s likely to be a wire disconnected in the fuse box,  asking unclamped contact when you move the harness.  Also quite possible is that the wiring has been damaged and has an internal break.

[Hawklord]

I have now taken off and cleaned all connections to starter motor and solenoid and removed, cleaned and refitted the big live wire to the under bonnet fuse box. I can't see how to remove the wiring harness wires from the fuse box though.  Looking at the wiring diagram is seems that the 60amp fuse feeds both the ignition switch and starter relay but as the ignition circuits are working ok I can only assume that the fuse box is functioning correctly. Have used the vehicle a few times today after the cleaning and it has turned over and started each time but there is that doubt in my mind and time will tell. For the cost of it I may change the starter relay anyway but trying to avoid £100 for the fuse box if at all possible. Thanks for your offer Steve b. 

[steve b]

Keep us updated  and let me know if you need a bit of help .

The connectors to that type of fuse box are usually released by a small flat blade (3-4mm) screwdriver down behind the terminal from the entry side -there is a tab on the large Lucar female tab connector to depress to allow it to slide out .

This wire can suffer from heat degradation ( hardening ) and cracking of the casing

Steve b 

[Hawklord]

Update - She has started every time since removing and cleaning the connections in the under bonnet fuse box

[steve b]

Excellent , problem fixed

Steve

[Sigi_H]

Another point of view:

My 200 Tdi will only start (but then reliably) when I push the key into the ignition lock. Only turning does nothing. Applying some pressure on the key 👍

maybe you do something like that without recognizing it

[ballcock]

The ignition switch is a common fault and they are not expensive or difficult to replace if you want to keep the original key you can just change the switch block on the back.

[Snagger]

On 8/15/2020 at 4:05 PM, Sigi_H said:

Another point of view:

My 200 Tdi will only start (but then reliably) when I push the key into the ignition lock. Only turning does nothing. Applying some pressure on the key 👍

maybe you do something like that without recognizing it

That is because the folded tabs of the outer steel case have straightened and aren’t holding the plastic base with the terminals tightly against the main casing.  Sooner or later, the base will slide out too far for that pressure to move the contacts into each other.  You can probably save the switch by removing it and re-closing the tabs with a hammer and punch.

[Sigi_H]

Thanks, I know about the reason. I just mentioned it, to see it as another cause

Edited August 17, 2020 by Sigi_H

[Snagger]

Fair enough, but I suggest you fix it before the engine cuts out while you’re on a motorway or pulling out at a junction with oncoming traffic.

[Sigi_H]

The switch is on my list 😁