79 300 no run?

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74scamp360

74scamp360

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i have a 79 chrysler 300 (cordoba, yes i know not an a body) i was driving down the road and started having some obvious electrical issues, the headlights went dim and started missing like crazy and just quit driving down the road, after countless hours now trying to figure out whats wrong im ready to give up, so heres what happens, it seems to have power while cranking because the car will fire, once you let the key into the run position it seems to lose power and then quits. now the car was a lean burn car, the previous owner converted it over to a regular electronic ignition system and car now uses a mopar orange box, i have tried numerous ballast resistors and helped nothing, we were able to trick it to run by directly powering the coil and it would run, unfortunatly now when cranking it wont even fire so i've managed nothing but make it worse, any ideas??? i can try and provide more info if needed, thanks guys
 
take the ECU box off, sand the piss out of its mounting points and tabs. re-mount the box tightly. check ALL your grounds while you are at it. if no worky, i can almost gaurantee a different good ECU will cure it, ask me how i know lol
 
i tried a new orange box yesterday, now like i said it has stopped trying to fire while cranking and i tried the new box after it stopped trying to fire while cranking so may still be the answer, but why wont it try and fire while cranking now?
 
gas is yes, i guess i have to check for spark again because its not firing while cranking, it did have spark, could i have fried the coil by jumping power right to it??
 
74scamp360 said:
gas is yes, i guess i have to check for spark again because its not firing while cranking, it did have spark, could i have fried the coil by jumping power right to it??
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Possibly , if it runs/sparks while cranking it could be ballast resistor . Sound like your altenator was bad originally , with the lights going dim before losing all power . Check alt and battery and voltage regulator , and the ground to ECU
 
have you checked your battery voltage? until you test it , you never know what it is actually holding

could be as simple as a weak or bad battery
 
i havn't checked it but we've been able to trick it to start which is wha makes me woner something electrical other then battery/ alternator
 
i had a similar problem once. 76 cordoba, 400, yanked the lean burn off, died just like yours, pulled over, replaced the alternator, fresh battery, new VR , fired right up never another problem
 
this just happened to me with the ECU box, i copied and pasted it from my other thread. you might want to read through it concerning charging problems. it has everthing to check with numbers. pay close attention to 67dart273 posts

http://www.forabodiesonly.com/mopar/showthread.php?t=173673

i recently had a problem develop. i would turn the key and it would not fire until the key was on its way back to the start position. i would crank it a few times , then it would start. it gradually got worse until it would not start at all. i pulled the ECU box off, stuck a new one on there, it fired and ran immediately. then a couple days later, it happened again. im thinking WTH? i pulled the ECU off, took a flap disc to the box mounting tabs and the fender apron where the ECU mounts and sanded all the surfaces to bare metal. i re-mounted the box, it has been working flawlessly for 2 weeks now.
 
i really think you arent getting spark because of something in the charging system contributing to weak/no spark condition to the distributor and not because of an ignition problem....its sounds to me

but thats without being there and sitting here at my keyboard. yes that was my disclaimer LOL
 
74scamp360 said:
yeah i know, hard to trouble shoot something you've neever seen before, all the same thanks for the help
Click to expand...

oh, ive seen it before and ive been there more than once lol . i have and have owned a number of 75-79 B bodies and i have yanked the lean burn more than once :D
 
Your problems are common to A-bodies, given the ignition mod.s Many, many posts on here about "no spark". Run a dedicated ground wire to the case of your ECU, don't rely on the screw. Make sure your engine is grounded to the frame and BATT-. Use an ohmmeter and measure the voltage difference in grounds while cranking. For the future, buy an in-line spark tester ($5).

I doubt that applying BATT+ to coil+ damaged your coil. I did that to drive my newly bought 64 Valiant home when it died (later found jury-rigged key-switch wiring). After 5 minutes, it started missing above 45 mph, but would idle OK. I touched the coil and it was very hot (and smelled burning plastic). I jumpered in the ballast and it ran fine the 80 miles home. Given that, unless the oil blew out of your coil, I doubt you hurt it.

Can you post a photo of your bulkhead connector? I don't know what the Cordoba uses. That is a common problem in A-bodies. If OK, next suspect the ignition key or the ballast resistor. I know that GM eliminated the bulkhead connector in 80's TBI trucks and just run the wires straight thru. I haven't checked my newer Mopars, but they might be the same.
 
Just a thought, You may want to pull the dash cluster and check the contacts at the ammeter gauge. if they become corroded or loose the charging system will not work properly and you will not be getting proper voltage to start.
 
I may not be much help here. I don't have wiring diagrams for a 79 Dobie unless you can post a link, and I believe they did away with the full current ammeter in them. That means the "usual" bulkhead connector problems may not apply.

But this still sounds like a problem like "bad bulkhead, BAD bulkhead!!!" or ignition switch, or wiring to/ from

Very FIRST thing is to get a factory or factory equivalent wiring diagram, or maybe even a reprint shop manual. If you get one on CD, it makes it easier to post sections of the diagrams or email them, etc.

One thing which I don't believe changed, is the way Mopar ignition works. That is, the ignition bypass (IGN2) I believe is still right in the ignition switch so if you have no ignition power "in start" it still should be one contact and one wire coming from the switch to the coil+ side of the ballast.

And "ignition run" (IGN 1) is the same, one contact on the switch, feeds the cluster power, and out into the engine bay feeding ignition, charging system, and some smog doo dads.
 
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