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No spark when cranking, starts in ON position

Dandesjar

Jr. Member
Joined
Aug 20, 2016
Messages
86
Ok, after 2 years of restoration my Bronco if finally running. Except for a couple of electrical issues it seems to be running pretty well. I’m still trouble shooting a gauge problem but my first priority is figuring out why I have no spark when I crank the engine. It won’t fire while I’m cranking but as soon as I release the key to the On position it starts to get spark and usually still has enough RPM from cranking to fire the engine. Anyone have some basic trouble shooting tips or ideas on where to start looking?

It has a new painless harness and ignition switch.
 

rmk57

Sr. Member
Joined
Feb 24, 2016
Messages
580
Try reversing the two small wires on the starter relay. Either that or you have something not wired correctly in the switch.
 

ransil

Bronco Guru
Joined
Sep 6, 2003
Messages
8,122
Should be an I terminal on the solenoid that sends voltage to heater ignition module you have to get it running during cranking, 12 volts comes grom a different place in run, you have that one correct.

Sent from my SM-G920V using Tapatalk
 

75MIKE

Sr. Member
Joined
Aug 22, 2001
Messages
955
Loc.
NE Washington
My Bronco was doing the same thing and I just fixed it with a new ignition switch. Do you still have your old switch you could try?
 
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Dandesjar

Jr. Member
Joined
Aug 20, 2016
Messages
86
I do. I’m going to give that a try first. I’m thinking the switch is probably good though... I have a FiTech unit and the white ignition wire that feeds it is powered when cranking so the switch is obviously feeding voltage to at least some components while cranking.

Does anyone know if there is a simple way to bypass the ignition switch by jumping the starter solenoid, rather than pulling the entire switch out of the dash to test it?
 

ntsqd

heratic car camper
Joined
Jan 30, 2005
Messages
3,224
Loc.
Upper SoKA
What ignition system are you using? This is a common thing to have happen with a Dura-Spark II conversion.
 
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Dandesjar

Jr. Member
Joined
Aug 20, 2016
Messages
86
I have an 6AL box, ready to run distributor, and coil ... so all MSD stuff.
 

bmc69

Contributor
Bronco Guru
Joined
Jun 11, 2004
Messages
11,851
The "I" post on the starter solenoid is where the ignition system gets it's power while the engine is cranking. Sounds like you are missing a connection to that.
 

ntsqd

heratic car camper
Joined
Jan 30, 2005
Messages
3,224
Loc.
Upper SoKA
......
Does anyone know if there is a simple way to bypass the ignition switch by jumping the starter solenoid, rather than pulling the entire switch out of the dash to test it?
"Short" from the battery + stud to the 'S' terminal on the relay. Before you do this, put a voltmeter or a test light on the 'I' terminal on the relay, see if it has power when you short it.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
Do you have a standard Ford starter relay like the original style? Or a more modern one that only has the small "S" terminal but not the "I" terminal?
Got pics of under the hood in that area?

Where is the White FiTech wire coming from? Directly from the ignition switch, or somewhere else?
Are you using a ballast resistor in this ignition setup? You should not be, so I wanted to make sure.

Things you can test easily with a volt/ohm meter:

1. If you have the Brown "I" wire connected to the starter relay, pull it off and measure voltage with the key in RUN. If it is not powered there is a break in the circuit somewhere.
In theory you no longer need this Brown wire anyway, since you are running an MSD setup that takes the full 12v of your system. But it should not hurt anything to keep it in place, as long as the starter relay is not shorting it out somehow.

2. From the back of the ignition switch, or up at the ignition box you will have a Red w/green stripe wire. Should have battery voltage in RUN, but should also have it in START, which it sounds like you don't have. However, you should test that theory anyway.
With both the Red w/blue "S" wire and the Brown "I" wire disconnected from the starter relay so the starter does not crank and you don't get a false signal to the other wires, have a helper turn the key to START while you test for full voltage at the Red w/green ignition wire. If power is present at RUN, but it goes away in START, your ignition switch is bad.

Remember, "new" does not mean "good" anymore.
And if any of those voltage readings you are taking are less than they should be, find out why. Even with all that wire, this new Painless system should have very minimal voltage drops along it's length.
If you find more than a half-volt drop anywhere, find out why.

Good luck.

Paul
 
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Dandesjar

Jr. Member
Joined
Aug 20, 2016
Messages
86
Man... great info.

Problem solved. I didn’t see any harm in reconnecting the brown wire between the I terminal & the coil. Evidently, with the 6AL box connected, the signal from this wire somehow interferes with the ignition system during Start. After some testing, I left this wire disconnected and it fires up right away with the key in start.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,345
Hey, congrats! Good to have it running.
Now on to the next bugaboo!;)

Paul
 
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