84 Full size - if 'resistance wire' is bad car dies when k..

Howdie - I found this post from 10 years ago. I have this problem
but think the post is a little bit inaccurate as the wire off the
starter relay is the one that does not use the resistance wire.

If I put 12v into one of the little wires off the starter relay my car
continues to run - this wire normally losses power then you come off
the start position. Any BTDT?


Make sure you are getting voltage to the pump before you replace it.
I
have an 85 Grand Marquis (same basic car) and it sends the full 12
volts
to the pump while the key is held over to start but feeds the pump
through a resistance wire from the starter relay after you let go of
the
key and it returns to run. If the resistance wire breaks the engine
will start but die immediately when you let go of the key. The
resistance wire on my Merc. is yellow and had printing on it every few
inches that says "resistance wire". I have heard of blue wires on
fords. To find the wire just follow the positive battery cable to the
starter relay and look for a very stiff wire about 1/8th of and inch
in
diameter connected to the
relay.

> Howdie - I found this post from 10 years ago. I have this problem
> but think the post is a little bit inaccurate as the wire off the
> starter relay is the one that does not use the resistance wire.

Ok, assuming that you mean that the car cranks, fires, and then dies as
soon as the starter drops out ...

There will be a ballast resistor, usually a length of wire run along the
bulkhead under the windscreen, probably with bullet connectors. This is
where your problem lies - It's faulty.

The car is designed to run very lean, and as a result can be a b*gger to
start. So Ford fit a lower voltage coil with a ballast resistor in series
so that it runs correctly from the 12V battery.

However, there's no way it will start, so the ballast resistor is shorted
out when cranking and giving the coil a higher voltage and stronger spark.

So the car cranks, fires, then dies because as soon as the (faulty) ballast
resistor is put back in series with the coil, the spark dies.

I had exactly the same problem with an ancient Fiesta many years ago.

HTH.

Al.