Fried electrics. !

[shithotfast]

Driving back from a great day out yesterday, almost got home when the engine died. 2 secs later tons of smoke from under the dash! Panic! Opened the front clip and disconnected the battery.

It seems the ignition switch was a bit too close to part of the chassis rails, and touched. Must have worn the insulation down (after 12 years!) and the brown main wire touched. It goes direct from the battery terminal to the ign switch - without any fuse at all. Not sure if the new cars/looms have this fused - anyway as a result that whole wire burnt its insulation and so the wires from the ignition switch to the battery are a bit of a mess. Concerned there wasn't a fuse there? Anyway - I guess the only thing to do is buy another loom and cut this section out and splice in the new section as the wire was of course right in the centre of all the other wires and they are a mess as well now.

Dont suppose anyone has an old loom, or part of an old loom before I buy a whole new one and bin 75% of it?

Anyway, bit of a warning as I will now put a fuse in line on the new ign wire.

[macgtech]

This is a known weak point in the loom - a lot of current goes through this point and without a fuse its asking for trouble. Our loom went up previously and we are fitting power relays for the fuel pumps so that the ignition barrel is low current only. We are also going to fuse the loom properly so each circuit has its own fuse which isn't the case at the moment with the standard loom.

Jonny

[MarkWebb]

Yes my ignition circuit modded to be completely low current using a number of relays and extra fuses. However I still have massive unfused cable running to starter motor. Must fit fuse but it is a little bit tricky at battery end. Have run completely seperate relay switched supp;y for ecu and HP fuel pump.

[Steve_D]

My ignition switch is now relay protected as it was getting so hot you could nearly burn yourself on it.
My car now has 16 relays and 22 fuses.

Steve

[spatz]

I agree, I have more or less completely rewired the loom in my car, all is going over relays and fuses and a mains kill switch.
There is a 100 amp main fuse for the big wire that runs from battery to the kill switch. From there the suppy is running to the fuses.
The starter cable is unfused as this is a bit tricky. For my next car I intend to run the lights and some ancillaries from the ultima loom, but everything
that requires power will have its own new thicker wire.
The loom really requires an update for LS engines as you have fuel pumps and ECU and they are both thristy.
I also noticed that some cheaper calbe ties that have sharp edges easily cut into the insualtion, so that is something you should really avoid.

[anonymous-user]

Most OEM battery +ve terminals (or the KL30 B+ distribution block mounted on said terminal) incorporate a fusable link designed to melt first if the starter cable is damaged (usually as a result of a crash) It might be posisble to incoporate one of these into your new wiring system?

The trick to is have this fusable link not covered in flamable insulation, so when it melts it does not cause a fire.

Of course the other, and probably simpler option is just to incorporate a battery cutoff switch within reach of driver....... ;-)

[k wright]

Steve at AutoBionics has offered to make a loom for the car that has only the circuits that are needed (no A/C or windshield washer, etc.) and said that he can make it modular allowing fitting to other cars.

Look him up. He is very familiar with the car.

[GTRCLIVE]

Always fit a Mega Fuse in-line from the battery disconnect and the main lives on the car for this reason. 150amp fuse will just protect you from a potential fire

http://www.vehicle-wiring-products.eu/VWP-onlinest...

Holders

http://www.vehicle-wiring-products.eu/VWP-onlinest...

Protects everything except the Starter motor main draw cable , as 2000 cranking amps hard to fuse..

[Storer]

We use a similar fuse in a Cerbera. It requires the fuse to be replaced regularly (annually) if it is not to fail at an inconvenient moment.

Paul

[Storer]

To those that have fitted many relays and reduced current in the factory loom.

How have you fitted them? In a bank and if so where? Or singly. Would you do it differently if you were starting from scratch with the body off?

Your advice/opinions would be welcome.

Paul

[spatz]

I am running two additional relays for circuuts which were available as I got rid of the the relays for the indicators (stalk)
this time I have ordered another 2 holders so can add 4 more relays altogehter, that should do it.
I will probably also go for a one or 2 external relays for the radiators, there are 70amps available they should do the job.

[anonymous-user]

GTRCLIVE said:

Always fit a Mega Fuse in-line from the battery disconnect and the main lives on the car for this reason. 150amp fuse will just protect you from a potential fire

http://www.vehicle-wiring-products.eu/VWP-onlinest...

Holders

http://www.vehicle-wiring-products.eu/VWP-onlinest...

Protects everything except the Starter motor main draw cable , as 2000 cranking amps hard to fuse..

You can use a Ford Transit battery earth cable, which has a fusable link built in:

[GTRCLIVE]

Storer said:

We use a similar fuse in a Cerbera. It requires the fuse to be replaced regularly (annually) if it is not to fail at an inconvenient moment.

Paul

Sorry what do you mean, I have used them in my GT40 and Ultima and never had them blow ? if yours where blowing you must have been on the limit of the fuse to often. Maybe you should have gone up another 25amps...

Fuses don't degrade..... only circuit breakers degrade and only then after multiple blows...

[GTRCLIVE]

Storer said:

To those that have fitted many relays and reduced current in the factory loom.

How have you fitted them? In a bank and if so where? Or singly. Would you do it differently if you were starting from scratch with the body off?

Your advice/opinions would be welcome.

Paul

Start from scratch If I was you, because you end up making a better job of it, and you can use the thin wall cable instead of the old stile heavy wall cable that was dumped by most car companies years ago.

[Storer]

GTRCLIVE said:

Sorry what do you mean, I have used them in my GT40 and Ultima and never had them blow ? if yours where blowing you must have been on the limit of the fuse to often. Maybe you should have gone up another 25amps...

Fuses don't degrade..... only circuit breakers degrade and only then after multiple blows...

Clive

Cerbera's tend to run quite close to the limit on a 100amp fuse and they do degrade to the point where they affect the ecu and injection system and cause poor running.

I have upgraded to 125amps to help avoid the problem but it is the cause of many questions about poor running on the Cerbera forum.

Paul

[spatz]

Storer said:

Clive

Cerbera's tend to run quite close to the limit on a 100amp fuse and they do degrade to the point where they affect the ecu and injection system and cause poor running.

I have upgraded to 125amps to help avoid the problem but it is the cause of many questions about poor running on the Cerbera forum.

Paul

yes could be but is then not a problem of the fuse itself but rather its connection to the fuse holder, if the fuse and holder is getting hot then something is wrong and you should clean the contacts.

[Steve_D]

GTRCLIVE said:

....Fuses don't degrade..... only circuit breakers degrade and only then after multiple blows...

Sorry have to disagree. In my experiance fuses do degrade over time but probably several years.

Steve

[YIIHAA]

Ultima factory said:

In summary the Ultima wiring system will perform faultlessly provided the build manual is followed.

Has the ignition switch, and the supply to fuse 1 been changed since 2001?

I had a very hot ignition switch, the key burnt my hand and the insulation on the connectors melted. I wasn't the only person with this problem. You can read about it here:
http://www.pistonheads.com/gassing/topic.asp?t=110...

My build was standard, and followed the build manual, all be it a version from ten years ago!

[deadscoob]

Question to the factory:

Is the dedicated loom only available from AS?

I will be sourcing an ls engine from elsewhere, I want to be as factory standard as possible which will include wiring, but am I being forced to use AS if I don't want to have a bespoke loom made?

Thanks.