Ok Guys,

Hopefully this might be the last post on the subject.

I think you must by now all know my problem (Low voltage to ecu when lights/ancillaries switched on).

I've sorted this problem out by running a cable from the + terminal on the battery, through a relay and direct to the ecu. I now get 12.5 volts with lights/ancillaries on.

However, on the + terminal of the battery, there are three small black cables, that are tails of larger cables. One of them was getting very hot, not only when using lots of ancillaries, but it was even quite warm just on tickover with no anciallries on. I'm trying to identify what this supplies power too, as this may point me to the original problem of something drawing alot of voltage.

On the + terminal of the battery, there are three small black wires which lead to (within a few inches) three larger cables. I guess these are basically safety tails, that would burn out in the case of an electrical problem before the mail power leads burned.

The three leads are as follows

The top black tail lead, leads to a red wire which is thicker..... This is the small black lead that seems to be getting hot, and I need to know where it supplies power too as this could be my problem.

The middle lead, leads to a Red Wire which is thircker, with a Blue Line running along it. (This is ok)

And the bottom lead, leads to a thicker Red Wire (This is ok)


Any help much appreciated.

As in earlier posts I have been advised to discard the three thin black tail wires and continue the thicker wires all the way to the + terminal on the battery.

I have some 27amp wire, which is much larger than the original black tail wires is this suitable ????

 

Jim, they ARE the problem. They feed various circuits on the fuse box and can't cope with the current draw from all the circuits.....

Cut them out as you have done and uprate them....

 

"do not just replace them with cable, use a fuse", those were karls words earlier this evening when speaking about this over a beer or 2 after the pod

 

Yep, or you could have a fire if you ever got a big short.

 

Yep, No Problem,Using 35amp Wire,

and 30amp fuse.

Regards Jim

 

BTT

 

is 30 amp enough jim, i think that will blow if you do the sums

 

make sure you know what they are feeding. as above, 30amp fuse is ok but if its drawing a higher load it will pop. also if it aint a higher load the unit/whatever maybe only 20amps thus a 25amp load will pop the unit/whatever and leave your 30amp fuse happy and un-popped !

 

BTT.............

RE : WHAT FUSE SHOULD i USE....

 

They look burnt LOL.....

 

BTT FAO DINGY

 

The top wire was abit crusty close to the terminal, but was ok after the first inch. But it was getting hot when using ancillaries (Full Beam etc)

I've done as the other guys have suggested and replace the three tail wires.

But the one I'm concerned about is the top one. (The burned one) I don't want to run it without a fuse just incase I have a problem (Dont' want the loom going up in flames) everyone tells me that this wire always gets hot, but I don't want to take any chances.

Just not sure what ampage fuse to run on the cable. And of course trying to find out what it supplies.

 

Depends what the wire was connected to...

If it was the chargin circuit try 50-100 amp fuse's starting off on the 50 and see if it runs fine, also put everythin on and see what current is pulled from this wire....will give you an amp rating...

If you have 30amp wire tho, the wire will burn before the fuse goes....usually

 

Jim,

As my loom is all out the car, I should be able to trace the wiring for you.

Sending that ignition amp today for tomorrow delivery if you still need it?

 

Hi Richard.

If you could trace that wire it would be great.

Yes : Please send ignition amp, let me know how much the postage is and I'll get it to you straight away. and either return of make you an offer if this solves a problem.

Regards Jim

 

jim my offer still stands mate.

anything you need to borrow your welcome to.

 

Thanks Ryan,

Will wait for peoples advice and let you know.

Thanks again

Jim

 

If it goes to the chargin circuit car then i would use some better cable...

Maybe replace the whole of the charging cable with some new decent cable...

 

That was my fear dingy.

Will wait for Rich to see if he can trace where it goes,

 

WHAT INLINE FUSE (Ampage) SHOULD I USE GUYS ??????

 

Jim, you can't get the answer untill u know where the wire is goin...

Its no good putting any fuse in if its not right....

It should go to a fuse, unless its chargin then usually goes to alternator....

try a 30 amp if thats the wire u have used....

 

TKS DINGY,

Have used 35amp wire, So i'll try a 30amp fuse to start with.

Still waiting for some info from Richard as to where it goes. But if I disconnect it. Then i have no ignition, no nothing.

Jim

 

The car should have all the protection it needs if it is standard wiring. If it has no fuse then replace with no fuse.

Some of the cables cannot be fused due to the potential current draw (starter main feed), but i suspect this cable does terminate into fuse anyway.

Be sure if you replace it to carefully check insulation (megger would be good but visual OK).

I can prob make you a few cables if you give me what size in mm2 and the length. I can crimp proper lugs onto the end if required or simply leave cut.

Cable will likely be ho7 double insulated (very flexible but quite thick) 16mm 25mm 35mm, 50mm, 70mm, 95mm or 120mm(Toilet roll size)

Depends if we have it, but if we do ill do it for the cost of postage mate.

 

Those 2 wires are not related to the charging circuit. They are something to do with the main fuse box feeds.

The only way to know what fuse to fit is to repair the wiring as it was before to Ford spec then switch everything elesctrical on that is fitted to the car (add 30-35 amp for the cooling fans, I don't think there is anything else that can't be tested easily) with the engine running and measure the current draw from the battery.

For this I used a DC clamp meter. Usually about Ł150 which is a bit expensive to use once. With my Dad's car and all his stereo equipment the total came to 106 amps but that included the charge rate which you should exclude to get an accurate reading....

 

hi jim if it of any use to you tomorrow i will run my car and take amp readings of the 3wires and let you know the current draw

 

Alan : That would be a great help if you have the time to do that.

Regards JIM

 

DON'T just cut the wires out without replacing with a fuse!

That looks like fusible-link wire and it's designed to melt if you have a major drama.

The red and red/blue almost certainly feed your positive busbars in the fusebox and the red/blue often supplies only the higher draw electrical options like e/w, heated bits and bobs, etc.

Best bet is to replace the fuse link wire with a ICE-style fuse board screwed to the bulkhead and run a short, very high current cable straight to the battery to solve the current dramas at that end.

*BUT* you need to find out where the overheating problem is coming from - my bet is that you have a small short circuit to earth in one of the unfused circuits before the fusebox, so check the wiring loom as it passes through any metalwork (e.g. at bulkhead pass-through). It could be something as simple as the fusible link wire not being large enough to handle the standard current passing through it, but you should check to make sure you don't have any other dramas on the +ve side of things.

Finally, I'll bet you a tenner that your earths are crusty as fook and they're causing a load of resistance on the car. Make sure all your earth points are minty clean and then sealed against corrosion with a good contact sealant or even paint, and replace any earth straps between chassis, engine, gearbox and battery if you can afford the cost (it's well worth it).

Not sure if charging circuit on a cos goes from alt direct to starter but I'd put money on that being the case; if so, get alternator off, clean up mating faces, clean up electrical contacts, and again consider changing over to fused cables instead of the shat fusible link shit Ford stuck on.

Good luck,

Al (Monkey with 0 qualifications to talk about what I just talked about )

 

jim the charging circuit goes straight from alternator to baterry this cable runs from alternator round the bulkhead and on to the baterry and maybe one of the cables you have pictured i know you have cleaned all earthing points so i guess no problem there has for things being down to earth i dont thing so the cables are probley getting hot due to being old and broke down cable does not last forever ( ie why do you have houses rewired ) i will have a close look tonight when i get home from work and take amp readings ect and let you know the only other problem could be bad connections in the fuse box causeing high risistance and over heating

cheers alan

 

Just seen this topic:

I discovered that one of those links on my car was all burnt out. There were no problems apparent with the car other than this burnt wire. I replaced like with like, and the wire has been fine since.

The only problem with replacing them was that I couldnt find a soldering iron big enough to solder into the main fusebox feed wires

Got there in the end though!!!

I have a SECS monitor, and that shows 13.2 -13.5 volts at the ECU under no load, and never drops below say 12.8 under full load - will check this later on for you

I couldnt figure out the purpose of the little blighters 100%

Neil.

 

PROJECT ST, ALAN & NEIL : Thanks for that advice guys, I'm going back into the garage and checking everything you've suggested before I do anything else.

Regards Jim

Alan, will await your testing tonight before doing anything drastic.

Cheers again guys for taking the time to help out.

Jim

 

Sounds like your getting some good advice their Jim....

I aint got a saff to look @ untill thursday so can't help.

 

Hey, No Problem Steve.

You've helped me out already.

Can you post that Cossie Wiring Link that you sent me a while back.

Cheers Jim

 

Was it this one?

http://www.derbyshire-rsoc.co.uk/cosworthmanuals/

 

Project ST : Just realised your in Pompey...... Me too, well Gosport actually.

Regards and thanks Jim

 

That's the one.......

Cheers Steve

 

they lare exactly the same as mine did on my k plate escos. they are downside of a fuse anyway and the only reason i can think they dropped the wire size is because where they sit, a thincker gauge wire would not fit so they used several smaller ones. replaced mine with 2 much thicker cables as, if you clean all teh fuse carrier off theat is on the +ve post of the battery , you will find that 2 are linked anyway and connact to the same wire that feeds the main fusebox.