Coil spark

Grandpa1961 · Mar 21, 2019

My ford 4000 loses spark when when switch is in crank position. Any ideas?

Grandpa1961 · Mar 21, 2019

It loses spark to the coil. It has spark when the switch is in the on position.

Keith Williams · Mar 21, 2019

Grandpa1961,
Which 4000 do you have? The early 4 Cyl or the later 3 Cyl.
Guessing it's the later 3 Cyl and the wire that provides power to the coil is disconnected.
There are 2 wires to the coil in that system. One that provides power thru a resistive wire in run mode. The second provides full voltage during starting for a hotter spark.
HTH
Keith

Grandpa1961 · Mar 21, 2019

It’s 3 cylinder gas

Jim L WA · Mar 22, 2019

I don't know about the 4000 series tractor, but the principal is that when you are in start or crank mode the ignition switch or the solenoid bypasses the run circuit to the coil. That start circuit is open.

Grandpa1961 · Mar 22, 2019

(quoted from post at 09:34:15 03/22/19) I don't know about the 4000 series tractor, but the principal is that when you are in start or crank mode the ignition switch or the solenoid bypasses the run circuit to the coil. That start circuit is open.

How do I wire it up where I get fire to the coil when cranking?

da.bees · Mar 22, 2019

The 2 small terminal posts on solenoid are marked S=start I= ignition and supply's 12 volts to coil ONLY while cranking. I recommend disconnecting battery cable from starter(wrap end or otherwise insulate)before prpceeding but if you are carful,it's not necessary. While key is in start or button is pressed for start,there should be 12 volts on I terminal. If not,solinoid is bad. If you find it has 12 volts,test at coil post. If ypu have 12v at solenoid but not at coil,the wire is broken.

rvirgil_KS · Mar 23, 2019

The switch or solenoid that bypasses a dropping resistor to apply 12 volts to coil when cranking does not disconnect the dropping resistor from the circuit. If bypass circuit fails coil should still have run voltage from the resistor.

If coil completely loses power when cranking the engine it sounds like a wiring or a switch problem.

Sean in PA · Mar 23, 2019

(quoted from post at 10:59:56 03/23/19) The switch or solenoid that bypasses a dropping resistor to apply 12 volts to coil when cranking does not disconnect the dropping resistor from the circuit. If bypass circuit fails coil should still have run voltage from the resistor.

If coil completely loses power when cranking the engine it sounds like a wiring or a switch problem.

The key switch only supplies voltage to the "run" circuit through the resistor/resistance wire when the key is in the "Run" position, not when in the "Start" position.

Coil spark

Grandpa1961

New User

Grandpa1961

New User

Keith Williams

Member

Grandpa1961

New User

Jim L WA

Well-known Member

Grandpa1961

New User

da.bees

Well-known Member

rvirgil_KS

Well-known Member

Sean in PA

Well-known Member

Similar threads