Author Topic: electronic ignition issues  (Read 1810 times)

Offline mopar70maniac

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electronic ignition issues
« on: October 19, 2015 - 11:26:07 AM »
hello group, was wondering if anyone can help with my intermittent spark issue on my 73 challenger... sometimes spark, sometimes none, usually none. I've installed a new ballast resistor and coil. the coil tests good as does the resistor. I get 9.4 volts to the hot side of the coil when not connected to coil, however it drops to 4.5 volts when connected, not to mention with key on, the ballast resistor heats up way too much in my opinion. I think I can exclude the ignition switch being that I get 9.4v to the ignition wire? I have not yet checked the air gap, but my thought was wouldnt I never get spark if that was the culprit? I'm thinking a short somewhere after the coil being that the resistor heats up? also, with the coil wire positioned near ground, it sparks when turning key off...not sure if that is normal. I'm currently waiting for a colored wiring diagram to hopefully back track and find a short... or could this still be the ignition switch? A frined suggested starter relay but it cranks over.... any suggestions?




Offline Chryco Psycho

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Re: electronic ignition issues
« Reply #1 on: October 19, 2015 - 10:53:45 PM »
You need to check the air gap , it can be intermittent if the gap is too large . make sure the ground is clean for he ECU.

Challenger - You`ll wish You Hadn`t

Offline mopar70maniac

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Re: electronic ignition issues
« Reply #2 on: October 20, 2015 - 10:40:08 AM »
thanks Chryco Psyco, I'll pick up a non metalic feeler guage today.

Offline dodj

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Re: electronic ignition issues
« Reply #3 on: October 20, 2015 - 08:10:55 PM »
You need to check the air gap , it can be intermittent if the gap is too large . make sure the ground is clean for he ECU.
:iagree:
Also it is normal for the ballast resistor to get very hot with the key in run. A new one will start smoking.
Scott
1973 Challenger  440 4 spd 
2007.5 3500 6.7 Cummins Diesel, Anarchy tuned.
Good friends don't let friends do stupid things. ........alone.

Offline Chryco Psycho

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Re: electronic ignition issues
« Reply #4 on: October 20, 2015 - 10:19:59 PM »
Go through all the basics dirst & confirm everything is OK , if it still has a problem then we need to dig deeper & get more info

Challenger - You`ll wish You Hadn`t

Offline Kevin71

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Re: electronic ignition issues
« Reply #5 on: October 23, 2015 - 06:43:43 PM »
What is the ecu and how does it interact with the ignition system.  Is this the voltage regulator?  And a change in voltage keeps it from running?

Offline JayBee

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Re: electronic ignition issues
« Reply #6 on: October 23, 2015 - 07:06:17 PM »
A picture is worth a thousand words. The ECU is the orange thing (comes in black and chrome too), the voltage regulator is beside it. Someone else will have to explain what it does.

John

1970 Barracuda convertible
2014 Toyota Avalon

Offline Kevin71

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Re: electronic ignition issues
« Reply #7 on: October 24, 2015 - 02:24:29 PM »
I see why I don't recognize it, I removed mine when I put in a MSD dist and 6AL.  Thanks

Offline mopar70maniac

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Re: electronic ignition issues
« Reply #8 on: February 17, 2016 - 10:25:45 AM »
turned out to be bad connection at ecu! make sure plug bottoms out before inserting screw.... thanks for all input!