Wont start issue on 74 Charger

[19Charger74]

I have a 74 Charger with a 360ci. FBO elec ignition system with 2 pin ballast.

Background on issue was last weekend. Car ran fine but noticed overcharging higher in rpm. Last weekend pulling out went for a drive around the block and it sounded like it was missing then back firing when you got on it, Also overcharging at higher rpm. ( Volt meter in car would go from 13.5/14V then pop up to 18+V when you increase rpm). I pulled back in checked timing and it was fine but figured to back it down a bit to be safe, Sits at 10* initial idle. Started it up, backed out and drove 10 feet then it just died. I noticed my accesory gauges (tach and oil pres/volt/water temp) all blew their lights and my fuse link blew.

I have been checking the elctrical for the past two days and i'm kinda lost.

 

[19Charger74]

I've checked the power under dash in "run" and get 11.89V (same as battery power). I measured this at the stock ampmeter and on booth red (battery) and Black (alt) feed lines. I have power to interior lights, dash lights, accesory gauges, exterior lights.
All fuses are good.
Engine bay- I've checked everything for power. ECu has good ground and power to ballast. Coil gets power (11.55V) in Run and Start. Ballast resister checks out with ohm test by multi meter. I've pulled the Coil out and checked it's resistance and even swapped it another coil (thats good) same issue.

I'm swamped because everything that needs power gets it, but the coil wont spark to the distributor cap....
I did a resistance check on the dist pick-up coil and it checks out. I have no idea what is going on with it.

 

[tpodwdog]

guys,,,correct me if im wrong but the ballast resistor should cut voltage to the coil from 12 v to something less than 12 v . im not so sure you should have almost 12 volts at the coil .

your meter spiked to 18 v because of a faulty voltage regulator! it should maintain 12 to 13 v

 

[19Charger74]

I've got another Voltage regulator i'll pop on today. Just curious but i put a ground strap on the voltage regulator bolt to the trans, this wont have any effect will it?

Also I've swapped out to a good ECU and same thing ( No coil Spark). I've put a jumped from battery to coil + and it still didn't spark.

I'll go check again and write down my reading at certian pieces in the system.

 

[67 coronet]

a charged battery should read 12.5 volts plus.you should have a ground from the eng(or trans)to the car,but i wouldnt have it bolted to the volt regulator,that may cause some problems not sure.spiking voltage could be an alternator internal short as well as a voltage regulator problem.i would pull the alt and have it bench tested to be sure.as far as no run problem,did you check the coil wire to make sure it is not burnt or bad.you should also be able to check for"on/off"activation at the coil with a meter.signal from the distributor pickup sends a signal to the coil creating an on/off signal while running(or cranking).you should be able to check this while cranking with an ohm meter.grounding of the signal wire to the coil is a common problem.check all the wires going to the ignition circuit for breaks or grounding as well.remember to check where the wires plug together for internal shorts you normally cant see as well.

 

[19Charger74]

I don't have any time to mess today but i went out and checked some voltage readings.

All on Run position
Battery -11.66
Ballast - Blue wire - 10.93, Brown wire -10.88
Coil - + 10.88, - 10.88
Interior - 11.64
Alternator - Black wire 11.06
Fuse link by Starter Relay -11.64

I'll try to check it all on the Start position tonight. Is there some kind of relay that lets the coil fire? I checked the distributer pick up and its in the resistance listed in my Haynes manual, gap is set also to .007 (didn't have a .008 gauge). Also i've tried it all with another ECU and still same issue.

 

[67 coronet]

you battery needs a good charge first off.should be 12.5 volts or a bit more.no relay for the coil,the signal is sent from the distrib pickup to creat an open and close signal to fire the coil.your pick up may ohm out correct but it needs to send an on/off signal as it turns.check for that.

 

[19Charger74]

67 Coronet - Thanks for the tips, I'll check it all tonight when I get home.

 

[19Charger74]

I went out and checked my Dist pick-up and it ohm'd ok but when i crankeed the engine i didn't get any reading. I popped in another dist coil pick and this one checks out but I still don't have any spark at coil... I checked this with the battery on a "start" Jumper that was feeding 14V so i knew there would be lots of power.

I'm going to check some more wires or something again.

Any one know if your sappose to have power at the coil on the Positive and negative side?

 

[19Charger74]

Had a few minutes to play with the car and figured i'd check the ECU connector for power and return power from the distributer. ECU is a 4 pin design (pin #3 gone on the 5 pin design) I have power at two pins except the two wired that go to the distributer. When cranking the engine i get a 0.02V reading. I know the Dist should send a signal back to the ecu but wonder if this is to faint or if that is normal.

I can't find any specs on voltage ratings in the ignition system or anyone who has had this problem.

 

[19Charger74]

well everything checks out for voltage and resistance testing. Car still wont fire and i'm lost for figuring it out.

 

[70rr-brian]

Pull your bulkhead connector and clean the spades real good.

 

[Ron 73]

Did you ever get this going?

 

[19Charger74]

Hey, got the car running for about 1 min then it just wants to shut off.

I had to get my friend over with a mechanics multi-meter. It can map all the voltage and to show you whats getting a signal and whats not doing anything (like the dist pick-up coil ) anywayswe tried two ECU's and we're stumped but figured it had to be the ecu. Ordered a Orange box and pop it on and she fired up.

So now i've been cleaning and re-wrapping all the electrical. I'm stumped now because the car won't run for longer then a minute. Fires up fine but then it just feels like it runs out of fuel.... I can tap the gas and it helps for a second but even holding the pedal at 1500rpm it'll just drop off and die. I noticed the ballast resistor is hot but the old one was always hot also. Voltage sits at 13.5V so its not getting over charged.

Always something to do with this car.

 

[loneagle]

I'd check the spark first if it was me they make a wire can't say were to get it but it has a bulb in it that lights while getting spark put it in then check to see if spark is there as its during as you might have a carb or fuel problem but that would be how id try to trouble shoot it I don't have alot of practical use on the 74 but fuel and fire most important you gotta see why its dying first fuel or fire

 

[19Charger74]

I thought i replied on here awhile ago. Turns out it was the ECU. My neighbor came over with a Mechanics electrical tested and mapped everything out. Said it had to be the ECU so i bought a Mopar perf one and she fired up no problems and sounded stronger...Can't describe it but i was getting a deeper sound from the car then before.

I found that if you use a Test light. Ground it and touch the ECU box on the little circle thats on the face, If it lights up the ECU module is bad.

I had that with 2 ECU on my car and th enew doesn't do it, I also checked some other Mopars and same deal. So save your self time.

 

[Bruzilla]

Thanks for posting this string! I was having the same issues with the 360 in my 74 Roadrunner. Dropped a new ECU in there last night and she's running like a champ!