Help---Mystery problem !!

Long story here...........I hope someone can throw me some ideas ?

Right now -----My dart----fresh motor . I have no spark from the coil . Months ago i fired up the car with this motor , and the timing was WAY off . It sounded crisp but wouldnt idle. This is just firing it up --so I had a buddy help fire it back up and the timing light said 60 deg btc ! So i backed it down to 30 and it wouldnt even start at normal timing...just sputter. Seemed normal when the timing light said 60btc....?

I recently looked at everything--looked at cam lobes , rockers , lash , cleaned the carb , timing chain+ gears .....Full on Leak down test----.even tried a new UNILITE that burned up in a couple minutes....a new coil , and a new MP ecu .

Now... Lets back up .......before i fired up the fresh motor last winter , i had a mishap. My buddy handed me the battery to put in the trunk , and i didnt have the light in the trunk.........i said ---Are you sure the Positive is to the rear? he said Yes................nope..... my dumass hooked it up.....backwards... we turned car on and had nice smoke by the engine....it burned a fusible link. Im still kicking myself for that.

SO----my buddy bought me a new chrome MP ecu.....I had the battery tested at Oreilly--tests perfect.. Nothing else looks hurt / burnt .

so tonight..i went and tried again--no spark and the ECU transistor gets REAL hot !! I had another ecu i plugged in---same thing--transistor gets super hot . I have 11.8v at both sides of the ballast...and both sides of the coil with ign ON . This is a MP distributor .

Nothing as far as wiring has changed on the car during this fiasco....

Im lost here............do i have 2 bad ECU boxes ? ive swapped coils..........the car ran weirdly with the new Unilite too...like the ignition is wayy screwed up . But it did RUN...........now..no spark ..


Yes i would love to scrap it all and put a switch panel in and a Msd setup---but no $$$$ to do that. Id like to find whats wrong with this setup because its worked great since 2008 !!

Did you test the pickup coil in the original distributor?

How did you connect the Unilite? It does not require the Mopar ignition amplifier box (the thing you call the ECU?), it just gets power, ground, and has an output to the coil. If you connected it as you would a Mopar distributor, yeah, it could burn up.

The alternator might not have liked getting reverse polarity, either.

I would set the damperner at 15 BTDC on #1 compression (or your known/preferred initial #) then set the dist so the magnet is dead even with the tooth & the #1 plug wire is above or near above the rotor. But first pull the yellow (ign) wire off of the starter relay to disable the starter & pull the #1 plug wire out of the dist cap & hold it 1/4 from a ground & seperate the dist zigzag pickup connector & drag the male terminal on the body half of the connector across the intake surface to make/break ground & see if the coil wire sparks to ground with the key "on" & with a helper holding it to "crank". this takes the dist out of the picture. Holler back EDIT what Squirrel said, confirm you have the right stuff in there

Screw a top dead center stop in cylinder number one and carefully check top dead center to make sure your damper didn't spin to double-check your timing issue. Lots of out of Country dampers are spinning.

Yep .

the damper isnt going to make my coil Not spark...im thinking its the coil and/ or the ecu............I can double check the dist pickup but i think i did and it was giving a pulse ...........again ive swapped both BUT , i dont know if the replacements were any good to begin with !

yes i had the Unilite wired correct

I think the clue here is nothing changed with wiring....it ran great until the battery incident .....i have no spark out of the coil , and the ecu Transistor is getting super hot . I have a Kill/ Run switch--its working ..and i have a starter button...its working . 11.8vdc to coil pos/ neg and same at ballast terminals

if my timing is off....im sure would still have spark out of the coil ...weather its 40 deg btc or 0 btdc

If you killed the Unilite, that's a sign there's an issue somewhere.

Verify that the distributor is turning when the engine cranks. The distributor gear pin could be sheared. It can still turn some on friction.

Try reversing the pickup wires. I had a similar problem in the past nd the car wouldn't even fire until I reversed the pickup wires.


Ron

if you have a 4pin ballast resistor, test its resistance. one side should be 5 ohms, the other 0.5 ohms. if you have a 2pin resistor, it should be from 0.25 to 0.5 ohms. all these tests with the connectors at the resistor disconnected for testing.

its good , 0.8 ohms

Update----

still have 12v everywhere it should

swapped in a new ECU ..........no spark ....grounded ecu case to battery neg direct ........no spark

brand new coil ........no spark , checked and swapped coil output cable .

pulled dist out to check pickup ---works fine .

swapped ballasts--both test good

I give up


going with new ignition..maybe a ready to run setup .

verified .

the plug and dist. wiring havent changed at all since it ran .

Something has changed or it would still run, correct
I would be checking the grounds with a ohm meter between the ECU, coil resistor and the distributor housing and block

Just a shot in the dark...about 100yrs ago I had a 67 Barracuda w/440... anyway one nite I went to a friends house and when I tried to leave no start /spark... every thing looked good just no spark. then I found one of the wires from the MSD-6C had gotten trapped under the Valve cover. Once I found and resolved the issue (plus learned another lesson about MSD's) it started right up...just a thought

I had a no spark issue about 12 years ago. Changed everything. Come to find out that one of the wires coming from the MSD 6AL box popped out a tad bit from the terminal. Pushed it back in and it started.

ill go over grounds with the meter 1 more time...i know the block was good--and i had a direct ground from Batt to Ecu...

ill check wiring again but i had 12v everywhere it should be-----

There is no magic usually in our old cars, you can fix this
The hard part is figuring out exactly what is causing the system failure
I've heard of more than one professional drag racing teams swapping out all the electrical parts and wires on a race car at the track between Friday night and Saturday along with doing the same thing on Saturday evening
Your issues make me think it has a corrosion or what we use to called a swinging open issue on a connection or terminal end, ends Especially when cranking the engine over putting a bigger drain on the electrical system Good luck

You got a broken wire some place in the system.

If you are using any of the factory wiring that could do it. The ignition should be all new wiring and soldered connections, leave nothing to chance. Grounds can go bad real quick. I had a battery to engine ground cable corode in less than two years and the car wouldn't crank!

Keep Chipping at it..... You will get it handled !!!!!!!

possible that something else other than the fuseable link burned up?
weird for 2 different boxes getting so hot, you have a true Gremlin there
Good luck