okay i've been trying to diagnose this problem now for a few days with no luck finding the problem. well what it is doing is while driving the ignition cuts on /off under load or sometimes idling.and i'm running a mallory unilite and there modules are know to blow with voltage spikes. this module has lasted a year about 2000 miles and two other prior to this one but the current one has lasted the longest. my battery is in the trunk and #2 grounds are on the rear subframe/trunk bulkhead ,firewall to bell housing and alternator bracket to front subframe and core support. the unilite grounds to the alternator bracket and i'm running a power filter to protect it against surges.

here is some tests i performed while diagnosing the problem and there results,see if you notice any problems :

UNILITE MODULE - 11.83 volts open 1.3 volts blocked then uncovered back to 11.83 volts
centuryperformance.com says 12v open 1-2 volts blocked then uncovered 12 volts

VOLTAGE READINGS - voltage @ alternator "hot" lead @ 1500 rpm 14.7 to 14.9 volts

voltage @ disconnect /battery in trunk @ 1500rpm 14.6 volts

voltage @ alternator "engine off" 12.46 v

voltage @ battery/disconnect "engine off" 12.46v

ac ripple test .03 volts after headlights turned on to remove surface charge and to turn on alternator


BALLAST RESISTOR -

ignition switch side - 10.85 volts @ idle 12.65 volts @ 1500rpm

coil side - 9.20 volts @ idle 10.18 volts @ 1500rpm

( 1.6 volt difference @ idle ) (2.47 volt difference @ 1500rpm)


COIL - accel super coil and accel is showing in there catalog at .07k ohms primary and 11.8k ohms secondary

now if i take my multi-meter between the (-) of the coil and the coil wire tower i show 10.65 ohms and that's the same reading i'm getting when testing the (+) of the coil and the coil wire tower so im a little confused here on that.

now i thought my autometer tach was grounding out so i disconnected it and the ignition still shuts off. i also noticed with a multi-meter hooked up to the ballast resistor when the engine cuts on/off there is no voltage change noticed.so i would appreciate it if i could get some help here on figuring this out

anyone got any clues ???

Chuck, I do not like the way the grounds are run. The body is never a good conductor for a ground like that. In my opinion you should be running 0 cable from the battery to the block on the ground side. I know a lot of people say the way you did it it the right way, I disagree. I'm not sure this will help you current problem, but it may stop the constant module failure.

Next time your at the Long Beach swap talk to Dave at Dave's HEI's booth. He is always in the first row across from the bathrooms on the other side of the fence. He knows this stuff like the back of his hand. Or his email is sparkman@earthlink.net . He was a member here but I think there were issues.

Chuck, I do not like the way the grounds are run. The body is never a good conductor for a ground like that. In my opinion you should be running 0 cable from the battery to the block on the ground side. I know a lot of people say the way you did it it the right way, I disagree. I'm not sure this will help you current problem, but it may stop the constant module failure.

Next time your at the Long Beach swap talk to Dave at Dave's HEI's booth. He is always in the first row across from the bathrooms on the other side of the fence. He knows this stuff like the back of his hand. Or his email is sparkman@earthlink.net . He was a member here but I think there were issues.


i'm getting continuity though from anywhere on the chassis or body . if i where to take a jumper lead from let's say the rear subframe that's where one ground cable is. then were a ground cable comes from the firewall to the bell housing and attach my DMM i get continuity. like i said i've checked all the ground locations and all get continuity from front to rear.

I had the same thing happen to me. I had replaced my horn relay (the ignition wires run through mine) and it had come loose. So it wasn't getting a good ground. Just a thought.

I had the same thing happen to me. I had replaced my horn relay (the ignition wires run through mine) and it had come loose. So it wasn't getting a good ground. Just a thought.

are you talking about the relay itself not being secured tight enough to the bracket ???

Yupp :screwup:

muscl car, how are you making out with this problem? Any luck figuring it out yet?

muscl car, how are you making out with this problem? Any luck figuring it out yet?

just threw in another unilite module the other day and it's not cutting out anymore i'm glad they're only $40 . but no i haven't figured out the problem yet i've checked and re-checked everything i can think of. i even rechecked to see if i've got continuity thru out the grounds in my car and they're strong.i can place a lead on the negative post of the battery in the trunk and get good continuity up in the engine compartment. i think that mallory has really bad products like the unilite if you go to either the mallory website or to century performance the leading topic is always "blown unilite modules why"

Chuck, continuity is a really poor test. Ford does not instruct us to use it much any more. Try this, it's a voltage drop test.

Set the meter to 12v dc scale. Hook one end to the battery negative terminal, and the other to the block. Crank the engine and see what the reading is. If it's .5 volts or more then I would run a continuous cable from the battery to the block. For a test use jumper cables from the block to the battery to see if it changes. You can run the same test on the positive side and look for the same deal.

Batman had many electrical gremlins with the same ground set up you have. He ran a cable from the battery to the block and I think it took care of all the issues.

i think i finally found out the problem today !!!!:whine: there's a loose connection on the ignition switch side of the ballast resistor :mad: .i've got two wires crimped into a connector that splices into one wire that goes to the ballast resistor. when that wire is moved around the ignition breaks up .it looks like the crimped wires are loose causing it.also noticed that i had a 16 gauge brown wire off the right side of the block in the large wiring harness had bare wire touching the block this wire was or looked like it used to go towards the starter at one time.

i'm going to repair the crimped splice tomarrow and see what happens. the other day when i was installing my headers i must of bumped those wires and the engine wouldn't start . so while troubleshooting i guess i touched those wires and it started right up. i could tell something was wrong because the tach lite is wired into the 12v hot wire that ties into the ign switch side of the ballast resistor.so the problem is before that possibly at that connection that's crimped together