• Welcome to ClassicBroncos! - You are currently viewing the forums as a GUEST. To take advantage of all the site features, please take a moment to register. It's fast, simple and absolutely free. So please join our community today!
    If you have problems registering or can't log into your account, please contact Admin.

No spark issue in Solid State ignition system

ksbronco75

Contributor
Full Member
Joined
Sep 6, 2010
Messages
312
I have a 1975 for bronco 302, I have a new ignition module new coil and a new pickup coil in distributer. I have been through all the diagnostic tests in my ignition diagnostic troubleshooting book. I have no opens shorts or high resistance in in the system. Still no spark Any ideas?
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,337
What color is the plastic grommet on the module? '75 should have green. A black or blue grommet module won't work without some rewiring.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
48,099
Also, pull the distributor cap and make sure the rotor is spinning.
The roll pin can shear and leave things spinning where they shouldn't. Of course, other, nastier things can do it too, but we won't think about those yet!

Did it just stop one day and you've replaced all of those items to try and fix it? Or did it happen after the replacements?

Paul
 
OP
OP
ksbronco75

ksbronco75

Contributor
Full Member
Joined
Sep 6, 2010
Messages
312
I drove it in the shop last January pulled to motor and installed a rebuilt 302, went to fire it for the first time to I had no spark, and the yes grommet is green. distributer is spinning correctly, I have to power to the white wire on the module in the start position this is the only thing I can find that is wrong, but the motor still cranks over.
 

jw0747

Contributor
Bronco Guru
Joined
Nov 22, 2006
Messages
2,434
Loc.
San Antonio, TX
assume you're referring to a Ford Duraspark ignition set-up. Link below is a good diagnostic plan in spite of being from Autozone. Also there are many write-ups if you Google "testing Ford Duraspark ignition module." If it's wired correctly and you're certain the grommet color correctly matches the year of mfg. then you probably have a faulty module or coil. IMHO new doesn't always indicate that it's good.

http://www.autozone.com/autozone/re...-IGNITION-TESTING-CHARTS/_/P-0900c15280054f8e
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
48,099
...I have to power to the white wire on the module in the start position this is the only thing I can find that is wrong, but the motor still cranks over.

One of the wires on your module actually is supposed to have power during start only. So I'm not sure that it's actually wrong.
What about the other wire? Does it have 12v when the key is just in RUN?

Just out of curiosity (for myself), how many wires in the different plugs, and what colors are they?

Did you test the coil only by direct power testing? This is where you disconnect the "horseshoe" connector, lay the coil's HT lead against the engine where it can jump a spark to ground, apply 12v to the "+" side, and then intermittently grounding and releasing a jumper wire from the "-" side of the coil to a ground?
On a functioning coil, this will produce a healthy spark each time you touch and then release the ground.

Sounds like you've taken the OHM readings on the distributor's new pickup coil?
Have you been able to put a meter on the leads from the distributor while the engine is cranking to see if you're getting a signal from the distributor trigger?
I'm not actually sure how that works, so Viper might be able to walk you through the tests there. I'm just thinking that this is another test you can perform. If you haven't already that is.

Good luck.

Paul
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,337
Measure the ohms between pins 9 and 10 at the distributor. Should be 400-800 ohms. Make sure 9-11 is at least 70K ohms. Pin 11 to ground should be less than .5 ohm.

Should have 12V on pin 4 with key on. Should have at least 6V to battery side of coil with key on. Should have at least 10V to pin 5 in start.

Other than that, make sure all the connectors are in good shape.
 

Attachments

  • 75 SSI.JPG
    75 SSI.JPG
    49 KB · Views: 18
Top