Ignition coil sparking before cranking/fuel pump

[11harris11]

1994 5.8l fi ford engine/omc petrol

The problems seems to be electrical, I turn the key to the first position and even before cranking the engine the spark plug coil is activating and fuel pump relay is rapidly turning itself on and off? Shuld higher and low pressure fuel pumps remain on when engine is started?

Before the engine was running fine, fuel pumps would prime and turn off in the ignition position, now they stay off in the ignition and starting position.

Also checked the fuel pumps and they are working fine along with their relay. It seems to be the switching wire that is jumping between 6 and 12v

Trying to get my head round this is a nightmare!
Any help would be much appriciated, thank you

 

[Bilgediver]

1994 5.8l fi ford engine/omc petrol

The problems seems to be electrical, I turn the key to the first position and even before cranking the engine the spark plug coil is activating and fuel pump relay is rapidly turning itself on and off? Shuld higher and low pressure fuel pumps remain on when engine is started?

Before the engine was running fine, fuel pumps would prime and turn off in the ignition position, now they stay off in the ignition and starting position.

Also checked the fuel pumps and they are working fine along with their relay. It seems to be the switching wire that is jumping between 6 and 12v

Trying to get my head round this is a nightmare!
Any help would be much appriciated, thank you

The coil and pumps should come on in the ignition position, however if you have a ballast resistor in the coil circuit then the measured voltage at the coil will switch between 6v and 12 v when starting as the coil supply bypasses the ballast resistor in the start position.

 

[William_H]

The rapid turning on and off of the fuel pump might indicate a bad connection somewhere. ie the high current causes the voltage to drop at a poor connection causing the pump relay to disconnect so allowing the voltage to rise so it tries again.
The sparking of the coil would reflect this change in voltage supplied to it. Suggest you try by passing the ignition switch as in the contacts that provide power to the ignition circuits when you turn the key on. In fact bypass all wiring battery pos terminal to ignition circuit. If this fixes the problem you have some bad connection or faulty switch. good luck olewill

 

[11harris11]

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[11harris11]

Thank you for your help!

I will by-pass the ignition switch and eliminate that. hopefully it is that simple.

also it dose have a ballast resistor which i will check out, as when the key is in the ignition position (not start position) the e-core pack has around 8 second delay before it starts sending volts to the coil pack, which can be heard.

here is a link to the engine wiring diagram

http://postimg.org/image/4tcjcdy9j/