71 RR Won't Start...Need Help!

Technical Question and Answer - On topic to 71-74 Plymouth B-bodies only.

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unionjack1940
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71 RR Won't Start...Need Help!

Post by unionjack1940 » Fri Nov 18, 2016 2:12 pm

Hey guys, so here's the scoop. Car was running strong just a couple days ago and I go to start it and it will not fire. I checked the ignition module, voltage regulator, ballast resistor, pickup, and ignition coil. All check good. I have an electric choke that barely opens since this problem occurred. I decided to swap the ignition coil out with a brand new one and when I did, the car started by ran rough with the electric choke not budging. I went under the dash and wiggled some wires around and it started again, but ran very rough. Shut the car off and tried starting again, nothing. My pal said it might be a bad connection underneath the dash. Any advice on what is going on? What should I be looking for? I have a strong suspicion it is some under the dash. By the way, all fuses checked good.
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71bird
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Re: 71 RR Won't Start...Need Help!

Post by 71bird » Fri Nov 18, 2016 3:32 pm

Take the bulkhead connector apart and try cleaning the connections. Deoxit 5 works very well.
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unionjack1940
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Re: 71 RR Won't Start...Need Help!

Post by unionjack1940 » Fri Nov 18, 2016 3:48 pm

Just the bulkhead and clean it? Should I touch any of the wire ends?
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unionjack1940
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Re: 71 RR Won't Start...Need Help!

Post by unionjack1940 » Fri Nov 18, 2016 3:52 pm

Is this on the firewall or fender?
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71bird
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My Cars: 69 Coronet 4 door.71 Road Runner. 71Dodge Tradesman 100 Van. 75 Dodge Dart. 95 Dodge Neon.
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Re: 71 RR Won't Start...Need Help!

Post by 71bird » Fri Nov 18, 2016 5:16 pm

Firewall. Do you have a service manual?
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unionjack1940
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Re: 71 RR Won't Start...Need Help!

Post by unionjack1940 » Fri Nov 18, 2016 5:24 pm

yes I have one it looked dusty and I used contact cleaner, but still no start
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Re: 71 RR Won't Start...Need Help!

Post by 71_bronze_gtx » Mon Nov 21, 2016 8:32 am

IF your electric choke is not opening, it's an indication that the "ignition" circuit voltage is low. (double check the choke - if it's like most of them, you have to open the throttle initially to set the choke closed, and this also sets the high idle stop on the carb. As you drive and the electric heater in the choke housing warms, and the throttle is operated, the linkage steps off high idle and the choke opens.)

Low ignition voltage is commonly caused by a bad connection, and quite often in the bulkhead connector, but it can be elsewhere. The blade connectors in the bulkhead connector and elsewhere not only become dirty and corroded, but also mechanically loose.

Someone with a decent voltmeter, some basic understanding of taking voltage readings, and knowledge of the wiring system could track these types of problems down. To understand the wiring system, extensive study of the factory service manual wiring diagrams is a must.

For starters, get a voltage reading at the electric choke with the key in the run position. When I got my 71, the voltage there was about 9.5 volts, with 12.6 on the battery terminals. Way too low, and indicating bad connections. As a temporary fix, I bypassed the bulkhead connector for the battery, alternator B+, and ignition circuits.

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Re: 71 RR Won't Start...Need Help!

Post by josephgiannini3 » Mon Apr 16, 2018 11:47 am

There is inherent problems with the 71 72 harness. Here they are.. the main power wire runs through the firewall connector through the am meter to the rest of the harness if the am meter wiring is bad or the meter is bad you will have intermittant electrical issues. There are also several friction tape fusable link connections. check those as well. These are most likely the under dash suspects. Second under hood. Loose started selonoid wire. check the contact and nut torque. Check starter relay connection. Also check connection to ballast resistor. From the starter relay is the junction to the lean burn electrical ignition system.. If points check condenser coil on side of distributor.

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