Diagnostic Help - No Electrics (at All)

Before I clear some space in my lounge to mount the Silver Surfer on a onyx plinth as an ornament I've had the issue again c:

Drove it back from the service at my Indy and all was well. Parked on the drive and a few hours later car unlocked via alarm fob, ignition on (all lights) and then when I went to engage the starter motor I heard the solenoid click..............then nothing. All went dead and total power off.

Tried fiddling with the key no joy (ruled this out). Few minutes later all lights on, go to turn over, solenoid clicks then nothing - dead again c: Left a few mins repeated and then started no problem.

I've since then tried to replicate the problem but cant. Starts every time, starter cranks perfectly and 12.4v on standing battery.

I've been reading up in Streather's book and there is a 'suggestion' poor connectivity to the starter motor can cause 'all sorts of electrical issues' and wonder if the demand by the starter on the battery (via the earth strap(s)) is causing a circuit break somehow :dont know:

I'm now leaning toward the battery/starter connectors so just ordered a new earth strap :what:

Sound about the right way to go :dont know:

Well ... hmmm .. you have an engine earth strap which could well be faulty .. But .. you have a battery earth strap that would still give electric power to everything else , something is dropping the entire battery connection to everything .. after re reading posts , im still back at what on the wireing diagram shows some sort of + ve connection point that several wires come off from that feed everything , its got to be at that point i think.

The starter draws a huge amount of current so thats breaking the connection thats faulty , its just so randome is the problem .. need it to pack up , easy fix then lol

tell you what .. take a long drive to Sussex and ill drag out a voltmeter and have a look for you

Demort said:

.. after re reading posts , im still back at what on the wireing diagram shows some sort of + ve connection point that several wires come off from that feed everything , its got to be at that point i think.

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Any ideas where this 'connection point' will be as it appears the positive wires run underneath the spare wheel and then up behind the fuel tank and I wouold expect them to go to the motherboard of the fusebox :dont know:

Positive runs straight to the starter iirc which isn't easy access. It's a common point for bad connection so worth undoing and applying copperslip on re tightening. One important point. Disconnect the battery + terminal before doing the job. A short to earth is easy to do in that tight space and will make quite a bang.

Ive been looking at the wireing diagram i posted on my first post to figure out this problem , at K 50 it shows the battery and the feed wires .. off hand i dont know location but we have a 964 in atm so ill have a look tomorrow.

Im expecting though that it will be in the fuse board , the board can be pulled up to inspect underneath .. hell of a lot of wires though and do it with battery disconected if you want to look.

There are four 4mm2 feeds from the battery, they go to the central electrics (3) and the ABS unit. The large 35mm2 cable goes direct to the Starter and then to the alternator.

Demort said:

Ive been looking at the wireing diagram i posted on my first post to figure out this problem , at K 50 it shows the battery and the feed wires .. off hand i dont know location but we have a 964 in atm so ill have a look tomorrow.

Im expecting though that it will be in the fuse board , the board can be pulled up to inspect underneath .. hell of a lot of wires though and do it with battery disconected if you want to look.

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Demort - you're a star :thumb: I've ordered a new battery earth lead and may as well get a new battery for the price. But I'm thinking if it's not at that end it must be the main +ve supply to the fuseboard so what that looks like feeding in will be useful. :what:

Feeds to the central electrics go to R11 term 3 and R41 (DME) term 3 on the board side. Another goes to Fuse 38.

I had a look and a chat with the guys at work , the connection i see on the diagram would apear to be a solder joint , or crimp point in the harness , its were 1 wire is split off to several others so unfortunatly its some were in the loom .. how ever i dont think it is that now as a problem with it would generate heat so you would have seen smoke , burning smell etc....

One of my collegues rembers haveing a problem with the feeds as they go into the fuse board its self , poor rail connection but it will involve lifting the fuse board to check ...

If you want to do it your self undo the thumb screw back and right in the fuse board and undo the allen key bolt in the side , lift out the plastic spacer ( white ) and the board will lift up .. your then looking for the large red wires

Disconnect the battery first.

If your not keen i take it you have a local indy , just get them to lift it for you to check the wire condition and see if theres a problem , its also good to do a "wiggle test " with the fuse board up and see if you can get the fault to occur.

My way of thinking is its something that needs fixing , hard to trust the car atm i guess so you will not drive it as much and thats not good !


.. i looked every where for a picture of the under side of the board but cant find one im afraid , and i couldn,t take apart a customers car to photo it for obvious reasons !!

Changeing the batery earth lead is a good idear though if only to eliminate it.

There should be a very large cable going to the starter and a single smaller wire leading off , this is the main electrics wire so have a good look at that connection .. its also possible that the car has been modified so might have other wires on the positive side , a lot of the cars i see have had this sort of thing done over the years as problems crop up and a bypass is often easyier than a trace and repair.

Demort/Ras - Many thanks :thumb:

OK I've been spannering today :roll: and I've done the following:

1. Lifted out fuseboard and checked main positive 'in' connections. Checked all other wires/connections/fuses/relays all looked OK. Had a general 'wiggle about' but not power disturbance.

2. Decided to whip out the clock and check the contacts on that to make sure they were clean/sound - dont ask me why. Now that was a tight fit and the rubber gaiter holding it must be as strong as the clasp on Big Joe's wallet :grin:

3. Removed the battery and earth lead. The twisted lead was to some degree 'ionised', copper still clear running through inner strands but it looked dodgy so it was replaced with a new one. In addition the earth to body connection point was given a good clean, again this and the joining wires (one goes straight to ABS unit) connectors were covered in something :what: so gave them a good wire brush.

4. Wacked on a new 096 battery as I managed to secure one for £41 with a 4yr guarantee, 76Ah and CCA 670A :grin: . I'm not convinced there was anything 'wrong' with my old Bosch S4 battery but from my detailed files it shows as being fitted 18.03.2006 @£66.39 Previous to that OPC fitted one in 2000 for the 'bargain' price of £162.10

Next job is to tackle the starter motor connections - clean off and tighten up to see if that sorts it.

Excellent job .. this is turning into a knighmare to fix .. im supprised it hasn,t cut out with all that work ....

Just a thought , you know your way around a car so .. can you rig up a bulb to ign feed wire or perhaps cigar feed wire ?

If the problem happens again the bulb will go out if its a total electric failure.

What im thinking is we might be missing something so if we can prove its a total electrics failure we are back to main feeds / earths .. if not we just have a cutting out problem and theres several other things that can be.

Zingari said:

Demort/Ras - Many thanks :thumb:

OK I've been spannering today :roll: and I've done the following:

1. Lifted out fuseboard and checked main positive 'in' connections. Checked all other wires/connections/fuses/relays all looked OK. Had a general 'wiggle about' but not power disturbance.

2. Decided to whip out the clock and check the contacts on that to make sure they were clean/sound - dont ask me why. Now that was a tight fit and the rubber gaiter holding it must be as strong as the clasp on Big Joe's wallet :grin:

3. Removed the battery and earth lead. The twisted lead was to some degree 'ionised', copper still clear running through inner strands but it looked dodgy so it was replaced with a new one. In addition the earth to body connection point was given a good clean, again this and the joining wires (one goes straight to ABS unit) connectors were covered in something :what: so gave them a good wire brush.

4. Wacked on a new 096 battery as I managed to secure one for £41 with a 4yr guarantee, 76Ah and CCA 670A :grin: . I'm not convinced there was anything 'wrong' with my old Bosch S4 battery but from my detailed files it shows as being fitted 18.03.2006 @£66.39 Previous to that OPC fitted one in 2000 for the 'bargain' price of £162.10

Next job is to tackle the starter motor connections - clean off and tighten up to see if that sorts it.

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Nothing is that tight Mr Z! :thumbs: for a solid solution.

been reading this?

http://p-car.com/diy/clockrepair/

it cured my car of the Xmas tree effect and random complete power loss..

kenloen said:

been reading this?

http://p-car.com/diy/clockrepair/

it cured my car of the Xmas tree effect and random complete power loss..

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Ken - one of my theories pointed to this as well hence I had a look at the clock but I've not investigated further yet.

You mention you had complete power loss? Was that everything ie no warning lights, no anciliaries working and obviously nothing on turn of the key - completely dead as if battery removed :dont know:

Zingari said:

kenloen said:

been reading this?

http://p-car.com/diy/clockrepair/

it cured my car of the Xmas tree effect and random complete power loss..

Click to expand...

Ken - one of my theories pointed to this as well hence I had a look at the clock but I've not investigated further yet.

You mention you had complete power loss? Was that everything ie no warning lights, no anciliaries working and obviously nothing on turn of the key - completely dead as if battery removed :dont know:

Click to expand...

Yeah exactly that. my feeling is that the Xmas tree is the effect caused if the engine is running (inertia? its not a static fault and doesn't last), not running you get zilch as if battery fully disconnected. I even replaced the ignition switch gear as it was mentioned on the rennlist forums. Clock resolved for me. oh i did notice it was worse when condensation was in the car which led me to think dry joints..