So today I was doing a little bit of wrecking and revving in the sierra and as soon as I stopped I got some smoke from under the bonnet and the engine stopped. Half a fire extinguisher later and a cool down I tried starting but no luck, checked a few things and its seems as though there is no power going to the coil pack, changed coil pack jus to be sure, even tried putting a live direct to the coil pack.
The wire that melted was a black wire going from the positive battery terminal from what I seen and then along the bulkhead with the wiring loom and inside the car at the big grommet.
Whatever this wire is for or whatever the problem is it is causing no spark and also making the temperature hand rise off the clock (as if it is getting a full live??)
Would anyone have any idea what might have happened here? Any help is appreciated, thanks

 

Looks like one of the fuse links has gone, could be feeding a few circuits. You need to replace it but you can do it with a fuse holder and wire. Only thing is you need to find out what made it go in the first place as there could be a direct short somewhere. Think it needs some investigation with a meter and wiring diagrams for reference

 

Thanks for the help, would you take a guess at what fuse link it may be? Or should I follow th melted wire back to its source?
And also since the coil pack and temp switch are both connected to the dash would this narrow it down any?

 

Right, the first thing is the ground for the gauge is shorted to earth, that is what is causing that problem.

The trouble though, is where the wiring has burnt, it could have shorted wires together etc inside, you may even need to cut a section of the loom out and splice another section in, I had to do this with mine where some numpty had done a dangerous bodge.

As said there are two fusiable links, one or both of them have probably blown due to a short in the first place, so it's not just a case of replacing them.

Does your fuel pump prime when the ignition is switched on? It sounds as if the live power is there as you have run another feed as well, but most likely there is a problem on the ECU side.

The coil is not connected to the dash, the only thing they share in common is they both share a switched power feed. The only thing that is connected is the rev counter.

Martin

 

Thanks again, its a case of stripping back the loom until I find a problem then?
I have my pump wired live so it will run regardless, would these fusable links be the ones located beside the ecu or am I completely wrong?

Also when I find the source of the melted wires will I need to find out what its connected to and replace/sort out that part or problem?
Wiring is not my strongest point so please bare with me here

 

Just a though, I fitted a new ashley 4 branch a few days before this, this would have been the first time it would have got really really hot, with it not bein heat wrapped and no heat shield on the bulkhead/tunnel is there a chance I may have melted the loom?
Car isn't home yet to investigate btw

 

Bump, the problem was a melted wire down near the exh manifold, replaced this wire and any other damaged wires, found a broken fuse in by the ecu, replaced, tried starting but no luck, changed coil pack, 'motorcraft' sensor below coil pack which wire went into(black wire), and changed ecu but still no luck.

Could anyone please give me any help as to what to do next?
Was checking spark but getting nothing until I noticed a random spark. the car will spark when the ignition is turned to on, but won't spark when turning over, what might be the problem here?

Thanks for any help

 

Try looking at the ignition amp, this is by the exhaust manifold on these models, it's a stupid place to have it due to the heat from the exhaust, as such these are common to fail, bearing in mind yours has been on fire it's most likely fried it, they don't like heat!

Don't know the sensor your talking about on the coil, I suspect it is in fact the supressor, although this is fitted into the ground side.

Also it's not a good idea to have your pump running constantly, in actual fact it is dangerous, as if you were to have an accident the pump would keep going, not good if fuel lines etc were fractured, hence why manufacturs do not do this in the first place

Martin

 

I think I have changed the ignition amp, this is the thing I was talking about below the coil pack and also by the manifold, just above the chassis leg, I see no other sensor there, however this didn't fix the problem, would I have damaged the cps from the wire frying?

Well my pump wouldn't work so I wired it direct to get it sorted, may try to fix that at some point too lol

 

I assume you rewired the pump before this problem?

You mention coil pack, these cars never had WS, I assume you mean a coil that connects to a distributor?

It's possible, only thing you can do is check the sensor/wiring.

Martin

 

Yea it was wired up before this happened,
I think its distributor I'm talking about, get mixed up in the 2 names.

Ok I may test that out, I really do hate wiring

There's also a suppressor module that the negative/green wire from the distributor, this wire got a slight melting too so is it possible that a suppressor module could blow or give up?

 

It could well do, however the suppressor will not affect the running of the car, it's purpose is to "suppress" the electrical noise created from the ignition system, that would otherwise interfere with devices such as the radio.

It's actually the coil your talking about though, you then have a thick King (LT) lead leaving this that connects into the center of the distributor.

The green wire ultimately connects to the ECU which is what switches the coil.

Martin

 

Hmmm, I guess I could test this wire and the black wire, but I lifted out the dash and can see nothing wrong in there, and nothing else wrong with the wiring in the engine bay, surely I'd notice if there was a problem with any of the wiring? And if nothings wrong it will have to be a sensor or something like that?

Yea its the coil then, I got into a habit of calling it a coil pack wich I guess I shouldn't have lol

Swapping a few sensors with a friends sierra to see if I can get it going, will let you know how I get on.

I guess there's a few relays that could possibly blow as well that would be worth checking?

 

The first thing you need to check is if you have a spark at the ignition coil?

To do so remove the king lead from the dizzy and hold with an INSULATED pair of pliers a few inches away from a good ground and have someone turn the engine over.

You should see a healthy blue spark jump the gap, if so then the coil and wiring is good.

Next make sure you have fuel reaching the engine, after that you need to work forward as to checking as to whether the spark is reaching the plugs themselves.

Martin

 

did u get sorted?

 

Gents

I too have a similair problem with a Mk 2 1.8 w reg mondeo. I have had ecu check and been advised ok. Replaced clutch, that I fried!!, and cam sensor but still no luck have had checked fuses both in engine bay and passenger bay, tried with replacement relays coil pack etc but nothing. Not getting fuel into engine (pump working) or spark at plugs so think it may be related to imobilsor or something but at a loss.

Now spent close on £500 but no joy.

Any ideas where next to look?