• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Possible Ignition Issue

67 Coronet Conv

Well-Known Member
Local time
2:14 PM
Joined
Dec 1, 2019
Messages
93
Reaction score
69
Location
Sacramento
Thinking I have some sort of ignition issue with my 67 coronet.
Went for a drive yesterday evening and about after 10 minutes the car died while coming to a stop. Cranked it and it came back to life and drove another 300 yards and it died and wouldn’t start again. After 5 min cranked it and it started for 1 sec and died and would crank but not start. When trying to crank it seemed like the battery was dying but after another 10 minutes would crank fine. Thinking I got some ignition issues, got towed home and check few things today on the ballast resistor and coil and spark. Car started up just fine today...thinking It’s something with the upgraded ignition.

Ballast resistor was reading between 1.5 thru 2.1 ohms, voltage was 9.6 and 4.43 on each side.
Coil (MSD high vibration coil-only coil that can be mounted horizontal per msd) voltage was 4.28 on the + and 1.26 on the negative.
Looks like I have a weak spark, It’s orange color, see photo

Any ideas? Thinking of just upgrading to msd ignition system.

Cars specs
440 30 over
Edgelbrock RPM performer heads
Holley 870 street avenger
Mopar intake
Mopar cam 312 .590” (?)
Harland sharp roller rockers
10.5 Pistons (what the guy told me)
727 trans
3.23 rear end

983601F5-A217-4EAC-BDEB-5CE0D8000374.jpeg 017E4A00-62AB-444C-B90C-DF418BECEDC1.png
 
Last edited:
What are you running for an ignition control box? Mopar ECU? Or are you still running points ignition?
 
Mechanical fuel pump ? Have you ever replaced the fuel pump push rod ? Could be a seriously worn rod that's barely stroking the pump.
 
You need 12volts to start with do you have a bad connection. Check wires make sure nothing is grounding out etc.
 
Running the orange box ECU.

I’ll check fuel pump rod and trace wire to see why I’m not getting a full 12 volts on one side of the ballast resistor. Could both of these issues let the car drive for 5 miles than die? When it died, I could see fuel still squirting into the carb.
 
OK common fails that happen when hoy is the pick up in the distrib and the ecu getting hot, when they cool down they run fine again.
 
If you happen to have another electronic distributor around small or big block.
Plug that into the harness and spin the shaft see how the spark looks with a different one.
That will tell you if the pickup is good or bad.
 
What would be the fix replacement?
You can replace the pickup coil and reluctor.
Test resistance on it and reluctor gap first.
But you need to remove the vacuum advance and take the distributor apart to change the reluctor.
I would just replace the pickup coil and skip the reluctor if it tests bad.
 
You need 12volts to start with do you have a bad connection. Check wires make sure nothing is grounding out etc.

Correct. Don't do anything until you find out why you don't have full voltage on key side of the ballast.

Usually the bulkhead connector Is a good place to check first.
 
If you happen to have another electronic distributor around small or big block.
Plug that into the harness and spin the shaft see how the spark looks with a different one.
That will tell you if the pickup is good or bad.
That is a good test, do it hot and cold to be sure, A hairdryer will get it hot enough.
 
Check out some more wiring and this is what I found

-when I unplug the ECU I get 11.4v at the ballast resistor and the Alt reg. When I plug in the ECU I get 9.7 at the BR and 10.1 at the Alt Reg. Does this mean anything?

Traced the Blue wire w/tracer back to the bulk head and got 10.4v. Attempted to trace it back to the ignition switch but I only have 5 terminals on the ign switch, there was not blue wire w/tracer. Wiring diagram shows there should be 6 terminals, anyone else have this issue?

checked voltage at all the ign terminals and they were all about 10.4. One was 4.4v and one was 0v. Mind you this is with the car in the on position not running.

The wire connections for the BR felt really hit when the car was on.

car battery is at 12.6v

Any ideas?
 
Unplug the ECU and do the same tests. Sounds like it's possibly drawing a bunch of current. Also check from the starter relay stud through the fusible link and through the bulkhead. Pull the bulkhead and check the connections.
 
I agree with don but also you are going to have to make sure everything thing is correct to the diagram. If it tells you six and you only have five to the switch where did the six wire go. Sounds like someone playing around with the wiring.
 
Ok so I checked the connectors at the bulk head all look good.

voltage at starter relay @ 12.5
Voltage at ignition switch with key off red wire is 12.7. With the key off is 10.7 this normal?

Also the ignition switch connector only has 5 prongs as does the key ignition. But the wire diagram shows it to have 6, missing dark blue wire with tracer or maybe it’s just not there. Need to trace it down on the inside of the car.

would my voltage drop as I turn the key on?
 
Auto Transport Service
Back
Top