electrical confoundation

[Anonymous]

howdy folks... try this one on for size: (Assuming DS II dizzy with DSII coil and fomoco ignition module on a 200ci) Ran a compression test on my recent rebuild, and found good results. Plugs etc replaced, went to fire up the motor. Turns over, fires, dies. Look things over, no spark. I figured I burned the coil being lazy leaving the key in the on position during the comp. test.... so I replaced the coil... no change... install spark checker.... key ignition, one single spark.... then no spark. Check power to coil.... light bulb power is there..... with key in run position and in start position. Humm..... bypassed the ballast resistor....... bang.... engine runs. Let it run for about 5 min... re-connected ballast resistor, runs fine. So apparantly the comp. test took the edge off the battery.... not so much that the engine wouldn't crank, but enough so the coil wouldn't fire with the ballast resistor in place. What could this mean? I installed the ballast resistor as stock for the DSII setup when I did the conversion.... I can't find the stock econo resistor... probably was removed or I'm a knuckle head..... we'll at least we know the second part's true for sure.

 

[addo]

It could also be a blown component in the DS-II box. I'd try an identical "known good" box and see what eventuated.

 

[fordconvert]

Resistor in a DS2 system???? I thought you had to remove it, why did you install one? My HEI setup seems to run ok with a resistor but I bypassed it with a relay anyway. I would say your theory about voltage drop is correct since I dont believe you should have a resistor in the circut.

 

[Anonymous]

As I recall from the sitcky article, when using the ford parts (control mod. and coil) you get power from the Pink resistor wire. I have heard, when using the GM module, no resistor is required. What coil are you using? Could you review your ignition setup?.... thanks...

 

[james singleton]

David, I am not familiar with the DS ll dizzy and DS ll coil, but I bought a 1.5ohm coil (40,000volt) instead of an 3.0ohm coil when I installed the Pertronix system on my 200cid. I can't remember where I read it, but if you don't won't to remove the resistor wire or ballast, then you need the 1.5ohm coil instead of the 3.0ohm coil. Like Fordconvert said, "why would you use the resistor"? If anything I believe you would want to remove it if you plan on using a 3.0ohm coil. Jim S.

 

[Lazy JW]

... So apparantly the comp. test took the edge off the battery.... not so much that the engine wouldn't crank, but enough so the coil wouldn't fire with the ballast resistor in place...

Not if it is wired correctly. The starter relay should send full 12 volts around the resistor to the module while cranking.

The early DS2 systems did indeed use a ballast resistor.
Joe

 

[Anonymous]

well, I figured out I didn't have the ballast bypass in place from the I terminal on my selenoid. So I wired that up. Cranked over nice. I noticed that the volts on my dash gauge were low... so I reved the engine hopeing for a recovery. ... this killed the engine.... checked,,, no spark when turning the key.... retried a ballast bypass from the ignition key, disconnecting the line I'd just run from the starter selenoid. ... still nothing....
Charged the battery,,,, headed back down for another try... went to the junkyard and got a bosch coil and a gm module to try next if this doesn't work...... pretty confusing for a weekender.... thanks to all ;..... David
SoCal

 

[fordconvert]

Check the pickup coil wires coming from the dizzy with an ohm meter. Orange and purple, the black is ground. Flex the harness around and operate the vac advance with a hand pump. Its possible that there is a break in the wire and when the vac advance moves it opens up and kills your spark. Also check your grounds like body-engine maybe when the engine torques you are somehow loosing the ground to the body or engine?

How are you confirming you are loosing the spark? Do you have some sort of tach? A tach will help to narrow things down, if the tach still works then you are looking at a secondary ignition problem like coil, cap, wires, and plugs. If you are loosing the tach signal then you are back to pickup coil and module.

 

[Anonymous]

well, got her runnin'. Found a host of things, I'm not sure which was the culprit. This is a vehicle I bought, and did not build, so I'm constantly finding things.
Someone had switched the leads on the starter selenoid because the wires for the alternator were too short to make it to the rear terminal.... I think this did some funny things when I connected a wire from the selenoid "I" terminal to the coil.... I think this blew the fuse for the ign module.... great learning experience there... though the fuse LOOKED ok, it was somehow failed, so checking all the wires for power as you suggested is what actually revealed the problem, not just checking the fuses...... thanks everyone for gettin' me back on the road! David SoCal