Re: 1971 Road Runner Running Issue
[Re: L.R Helbling]
#2299022
05/04/17 05:26 PM
05/04/17 05:26 PM
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Joined: Nov 2015
Posts: 96 NEW JERSEY
moparfury1970
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OP
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NEW JERSEY
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First do a resistance test on your ignition coil to see if the resistances on primary and secondary side of the coil are within tolerance. Check the coil service manual for ohm resistances to check. If it is a factory coil, check the FSM for ohm resistances to check. If they are not, junk the coil. If they are, continue with a dynamic test and wear rubber gloves and eye protection. With your car running, pull the high tension lead from your coil at the coil very slowly. The spark should jump a gap of an inch or so visibly and audibly with no trouble. If it is not, if it is sputtering and quiet your coil is fried possibly because of your 4 prong ballast which does not match your existing coil.
Had the same thing happen to my 1971 Roadrunner with the exact same symptoms. It may be worth a try. What coil would match a 4 prong ballast resistor? Right now I have a 12v red MSD coil.
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Re: 1971 Road Runner Running Issue
[Re: moparfury1970]
#2299066
05/04/17 06:50 PM
05/04/17 06:50 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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do you have another ign coil that you can borrow/sub in for a quick test.
live every 24 hour block of time like it's your last day on earth
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Re: 1971 Road Runner Running Issue
[Re: moparfury1970]
#2299079
05/04/17 07:15 PM
05/04/17 07:15 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
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Posts: 36,041
Lincoln Nebraska
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car doesn't seem to be acting now. All good or still acting up? EDIT Accell wants a .7 ohm ballast with that big yellow beast & your 4 terminal "dual" ballast will for sure have more than that. You might wire it in parallel (just add a blue loop on the other end also) to get the most out of this combo. That will work fine with your 4 pin ecu.
Last edited by RapidRobert; 05/04/17 07:19 PM. Reason: more info
live every 24 hour block of time like it's your last day on earth
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Re: 1971 Road Runner Running Issue
[Re: moparfury1970]
#2299082
05/04/17 07:18 PM
05/04/17 07:18 PM
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Joined: Dec 2016
Posts: 381 Ottawa, Ontario
L.R Helbling
enthusiast
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enthusiast
Joined: Dec 2016
Posts: 381
Ottawa, Ontario
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First do a resistance test on your ignition coil to see if the resistances on primary and secondary side of the coil are within tolerance. Check the coil service manual for ohm resistances to check. If it is a factory coil, check the FSM for ohm resistances to check. If they are not, junk the coil. If they are, continue with a dynamic test and wear rubber gloves and eye protection. With your car running, pull the high tension lead from your coil at the coil very slowly. The spark should jump a gap of an inch or so visibly and audibly with no trouble. If it is not, if it is sputtering and quiet your coil is fried possibly because of your 4 prong ballast which does not match your existing coil.
Had the same thing happen to my 1971 Roadrunner with the exact same symptoms. It may be worth a try. What coil would match a 4 prong ballast resistor? Right now I have a 12v red MSD coil. Whatever coil can work when matched to the resistance of your 4 prong ballast. If you really want to keep the 4 prong, test it to make sure it really does have a resistance of??? i dunno...let's say it's supposed to be 1 ohm. If you read 1 ohm on your multi-meter, shop around for a coil that will work with a resistance of 1 ohm. It should be marked on the underside of the ballast but if not there do a Google search to see what it's resistance should be. But first make sure your coil is bad before you start doing all that.
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Re: 1971 Road Runner Running Issue
[Re: moparfury1970]
#2299085
05/04/17 07:20 PM
05/04/17 07:20 PM
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Joined: Dec 2016
Posts: 381 Ottawa, Ontario
L.R Helbling
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enthusiast
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Ottawa, Ontario
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yes,i swapped out the msd with a yellow accel super coil. car doesn't seem to be acting now. Sounds good. can you get the spec for the yellow Accel if you are going to leave it in the car? It would be nice to know what ballast resistor is needed with that coil.
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Re: 1971 Road Runner Running Issue
[Re: moparfury1970]
#2299160
05/04/17 09:19 PM
05/04/17 09:19 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
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Circle Track
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Lincoln Nebraska
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the last 4 terminal "dual" ballast I parallel wired gave me 1.1 ohms which will work fine & is above the .7 ohms Accell wants for a minimum with their supercoil & that amt (1.1) is lower than what your 2 terminal "single" ballast will have. EDIT Assuming you don't have the 641 MP "race" 2 terminal "single" ballast (has .25 nominal ohms).
Last edited by RapidRobert; 05/04/17 09:26 PM. Reason: more info
live every 24 hour block of time like it's your last day on earth
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Re: 1971 Road Runner Running Issue
[Re: moparfury1970]
#2299167
05/04/17 09:27 PM
05/04/17 09:27 PM
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Joined: Feb 2003
Posts: 16,150 Mesa, Arizona
dart4forte
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 16,150
Mesa, Arizona
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Your problem is ignition not fuel. Did you change out the orange box or visa versa? My bets are on the box. Do you have any other spare boxes? Also, it may be the box is not grounding. I had a similar issue with an orange box. Is the box bolted to firewall? You may want to run a separate ground wire from the box to a common ground. I did that and it was problem solved.
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