3.9 non starter

This one has got me foxed.
The motor turns over but no sparks from the ignition.
Can get the king lead to earth out and spark by disconnecting/reconnecting power to the coil with the ignition on but no sparks when turning the motor over.
This happened very suddenly, the motor has stopped/started fine all day and no extra lights have lit up on the dash to indicate a fault, the rotor arm turns with the engine so I guess that rules out the drive on that shearing and I can hear the fuel pump kick in when I turn the key.
If it was a mechanical fault I'd probably be ok but I gotta admit I'm pretty crap with electrics :doh:
Any ideas would be appreciated please.

does it have a ballast wire to coil?

hall effect sensor is shafted or the amplifier is shagged.

what you have is feed to coil but no switching.

either millivolt or frequency range on multimeter remove amplifier and check pickup.
or the wiring has shorted down

ere Fanatic - wotcha know about 3.9's?

What exactly do you wish to know?

I dont - but MJLTigger might - yu far from Trowbridge?

65 miles or so

bit of a trip? .

what's the issue with it?

PM on way

sounds like blocked cat one bank.
Have said I'll look at it if he comes to me.

he said. i fink he is gonna get it decatted and then try agin.

TA.

stinking hot on one bank and cold on the other, hollow sound one side and not the other-sounds like cat has broken up.

sounds like a tratta and not revving over 2k.

fanatic said:

hall effect sensor is shafted or the amplifier is shagged.

what you have is feed to coil but no switching.

either millivolt or frequency range on multimeter remove amplifier and check pickup.
or the wiring has shorted down

Click to expand...

Thanks for the pointers Fanatic.
(Now I'm gonna prove how crap I am with electrics)
What do these parts look like and where do I find them?

the coil is a round toobie looking thing on the front panel with a thick wire going from it to the disty cap .

if yours is a Lucas distributor
(label on side and originally black cap) then the sensor is under round black cap beneath rotor arm
(says do not remove on plastic and 3 cross head screws)

The amplifier is bolted to the side of the distributor with two bolts and has a plug on it.
You will need to unbolt it to get to sensor wires.
If you need to remove the distributor then be sure to time it up and be sure before you pull it.

The amplifier switches earth
so the options are
1)wiring earthed out
2)faulty sensor/incorrect air gap
3)faulty failed amplifier

fanatic said:

if yours is a Lucas distributor
(label on side and originally black cap) then the sensor is under round black cap beneath rotor arm
(says do not remove on plastic and 3 cross head screws)

The amplifier is bolted to the side of the distributor with two bolts and has a plug on it.
You will need to unbolt it to get to sensor wires.
If you need to remove the distributor then be sure to time it up and be sure before you pull it.

The amplifier switches earth
so the options are
1)wiring earthed out
2)faulty sensor/incorrect air gap
3)faulty failed amplifier

Click to expand...

No amplifier bolted to the side of my distributor, just a plug and 2 wires going straight into the side of it.
I do have the black cap with the'do not remove'/3 screws though so that's where the Hall sensor is.

Ignition Amplifier Module
your module may be relocated link above shows it.
Under the do not remove plate, there is an 8 pointed star and a sensor- as the point passes the sensor (crank engine and can be measured with a meter) it causes a pulse that triggers amplifier (power transistor) to switch coil

fanatic said:

Ignition Amplifier Module
your module may be relocated link above shows it.
Under the do not remove plate, there is an 8 pointed star and a sensor- as the point passes the sensor (crank engine and can be measured with a meter) it causes a pulse that triggers amplifier (power transistor) to switch coil

Click to expand...

Yep that makes sense, it's bolted beside the coil on mine, thanks for your help bud, let you know how I get on