No spark when cranking but tries to fire as soon as I let off the key.

[cloby]

Hello. I have a 1972 Dodge Coronet Custom and I have no spark when cranking. Here's the weird part though. When I let off the key it kinda stutters like it's going to start. Before that I had a problem where it would just stall out randomly. I tested everything ignition related and it all seems proper. Could it be the pickup coil or reluctor? I tested the gap with a feeler and it's about 0.008. Some help would be very much appreciated as this car is my daily driver.

 

[Don Frelier]

Check your bulkhead connections.
Pull it apart, inspect, clean and put it back together.
You can pull off the coil wire and hold it 1/4" from a good ground and test while cranking.
Also test by putting the key in run and jump the starter relay with a heavy wire.

 

[furious70]

It's the ignition switch or ballast resistor circuit that controls the start vs run power

 

[moparwacko]

Replace your ballast resistor

 

[Dave6T4]

Ballast resistor or magnetic pick-up in distributor.

 

[dadsbee]

He says it doesn't fire WHEN cranking. It starts when he lets go of the key. Ballast is fine...

 

[440 4 speed]

He says it doesn't fire WHEN cranking. It starts when he lets go of the key. Ballast is fine...

I had the same problem probably 40 years ago. I think it was something fairly simple.
Do you have the solution?

 

[sam dupont]

I would spray the connectors and sockets with dioxit and stick the plug in and out a number of times. Then rinse.

 

[gtx6970]

Ballast resistor or magnetic pick-up in distributor.

This

 

[Geoff 2]

Could be ign sw.

 

[Kern Dog]

I've had this very thing happen numerous times and never found a smoking gun.
I did pull the bulkhead plugs, clean the terminals and pack them with dielectric grease....and not had an episode in 2 months.
That may mean nothing...I sometimes went several months between incidents. Time will tell.
What i did is good practice regardless.

 

[Nacho-RT74]

If where just a starting issue could be Bulkhead or ignition switch.

Track and clean the brown wire between ign switch and ballast.

Check if you get power while cranking on brown wire down the column.

Now, if randomly stalling… dist pick up coil, pigtail, or related wiring up to the ECU could be added.

IF NOT the ECU itself.

A ballast check would worth the try. The ECU gets its power while cranking still with power coming throught the ballast from IGN 2 circuit.

 

[BB BELLA]

engines with points and power supply for full ignition power in crank fed through "I" starter solenoid terminal will do this when they have a bad starter solenoid! I've only seen it on GM mercruiser.
I'm not that familiar with mopar wiring to know if they ever used that setup!

 

[BB BELLA]

first thing I'd do is put a voltmeter on battery while cranking to see how much current is being used by starter! if it's dropping batt. voltage too low ,you won't have good spark!

 

[ruffcut]

I saw this post yesterday and was thinking bulkhead connector also. I had this problem with a 72 Power wagon in the 80's.

 

[Ron H]

had a similar hassle, some call it 'run-on' - usual go-to's are the ballast and ig switch. Found a poor connection at the ig wire at the BH, it would become loose from normal vibration. Also had overheated the contact in a new harness so had to replace the connector.

 

[WileERobby]

Before shooting arrows all over the place, the first thing to do is ensure all connections and wires in the ignition circuit are tight and clean.

 

[Car #4]

I had the same thing happen. Car wouldn’t start when cranking but would when I realized the key. Replaced the ballast resistor and all was good.

 

[BeepBeepRR]

 

[Nacho-RT74]

engines with points and power supply for full ignition power in crank fed through "I" starter solenoid terminal will do this when they have a bad starter solenoid! I've only seen it on GM mercruiser.
I'm not that familiar with mopar wiring to know if they ever used that setup!

Mopar never used a resistor wire but a ceramic piece with a resistor in it. And the cranking feed to the coil comes from ign switch untill 75/76. Then was changed to the starter relay.

Anyway, he is working on a 72, that COULD get optionally electronic ignition. He is talking about pickup coil and reluctor so, if factory or upgraded he is anyway working on electronic ignition.

Did GM products still got resistor wire with electronic ignition? Dunno.

On 73, electronic ignition become standard.