Ignition Problem

[momack55]

 
Could someone help with this?   Cruising the Freeway........'70 Challenger, 440, 727, 4 barrel, standard ignition system....she just cuts out!!!!   Finally get her to run again...get home....wont start again to get her in the garage....turn the key, she fires and wants to start...let go the key....she dies!!!

Sometimes she will run then not!!  tested the ballast resistor....0.8ohms....bypassed with a wire...she ran, then didnt, then did.....I am at my wits end....is this the EIU, the Ballast resistor, Dizzy condensor, coil, or the regulator?   HELP!!!

Or do I just chuck the whole system for a MSD Ignition system and forget the whole ballast resistor stuff!!???

Hope someone can help!!!

Mozz!!

[Jamiez]

I would try swapping out the coil/ballast if you can, they are usually pretty easy to access and connect/disconnect.  If you could borrow a set for a test that would be ideal.  Swap them in see if it improves..if it does go buy new ones, if not move on to something else

[Chryco Psycho]

Check the gap in the dist the pick up should be .008 from the reluctor

[HP_Cuda]

Ballast resistor would be the cheapest and simplest solution to start with.

Past that check your fuel filter if you have one.

[RzeroB]

I had the exact same thing happen to me with a '72 340 Cuda I had. It would quit just as if you had turned off the key and wouldn't restart. Then after randomly different time intervals it would start up only to quit again at some point further down the road. Drove me nuts. I couldn't figure it out so I systematically started substituting each piece of the ignition system with a known good part. The problem turned out to be the ECU (Electronic Control Unit). Something inside of it had apparently gone bad. I replaced the ECU wit a MP chrome one and the problem was solved.

Since the Cuda was a '72 it had factory electronic ignition. In your post you state that your car is a '70 and has the "standard ignition" - so does that mean you still have points and a condenser? If that's the case, disregard my troubleshooting idea in my first paragraph as it obviously won't help you. However, later in your post you state "is this the EIU" - does that mean you have an electronic ignition? If so, my first troubleshooting idea may help you. If so, swap out your ECU with a known good one and I bet it will fix the problem.

[momack55]

Thanks RzeroB,

Yes I have the Electronic ignition...ECU, Ballast Resistor, reluctor gap dizzy.
I feel you may be right, I had the same problem in my 73 Chrysler, 360. She just quit and some time later would run for a while....changed ECU and away she went, but that was 30 years ago...my memory aint so good.  I'll have to systematically sort it I supppose....Thanks again.

Mozz!!

[RzeroB]

Glad to help. Swap out that ECU first as it seems the most likely culprit. When mine went out I didn't have a spare, but my friend did, so I borrowed his for troubleshooting. I didn't want to spend money replacing something that may have been good. So once I determined it was the ECU I just went and bought a new one and the problem was solved.

[Chryco Psycho]

Check the gap first , it is free !!
 You may want to look at the Rev-n-ator ECU

[Rich G]

I ran into the same problem with an aar cuda I was working on. Would only run when the key was in the crank pos. As soon as you turned it to the run pos. it shut off. It did turn out to be the coil. Check the ground on the ECM also. I keep a spare coil, ECM, and resistor in my car. Its my Mopar survival kit for road trips. Fits all my buddies cars and it gets you out of a jam quickly.

[momack55]

Thanks everyone!!  It was the Ballast Resistor!!   New one shows 1.6ohms......the old one had the back packing missing and the contacts were loose...the ECU looked real old and corroded so I bought a new one anyway.....next....the dizzy is lookin real tired and the coil looks older than me!!!    I think a whole set of plugs, leads, coil, dizzy, and regulator may smarten things up...it is pretty cheap to do and I need the peace of mind!!!

Cheers from Australia 

Mozz!!