Hi all,

After several years of flawless cold/damp startups, my 122 has begun being difficult. In hot, dry weather, the car fires up fine, but in cold and damp, it refuses to fire up the conventional way, i.e. by turning the engine over with the starter motor. Interestingly, if I roll it down a hill and bump start it, it fires right up.

Vital stats:

The battery is new and fully charged
There is no arcing going on under the hood
The points, plugs and condenser are brand new

Any ideas on what might be behind it? And in particular, why it should fire up with a bump start but not the regular way?

Any suggestions/wisdom are appreciated.

Floyd R.

Thanks everyone. I swapped in a new distributor cap and wires, and now the car fires right up in the fog.

Much obliged,
F.Ramp

Floyd;

I suggest you inspect the "old" cap and rotor for carbon tracks, and wipe it out with a clean paper towel to inspect carbon dust...if you don't find a specific carbon track, C&R can be super-cleaned with carb cleaner and retained as a spare.

Cheers

One possibility consistent with data and symptoms: Impaired conductivity in major electrical cable connection(s) excessively drops voltage and thus current through ignition coil when starter is activated but not when coasting to bump engine over to start it. This happens with coils built for nominal battery voltage without any in-series ballast resistor that is bypassed when starter is being used. Verify voltage to coil when and not when starter is being operated.

Cog makes a good point. I notice an omission in your replaced parts list--maybe replaced but not listed--a distributor cap--next to bad wires probably the most common cause of poor starting in damp weather. Also, on a bump start the motor is spinning much faster (even using top gear) than when on the starter. It may also pay to check the starter draw. It's been a long time since doing such a test with a simple inductive (is that the right term?) draw tester but I think you'd see something like 150-200 amps with a good starter--upwards of 500-600 with a bad starter.
My own personal best example of finding the cause of bad starting in damp weather was in 1969 in Kansas City with a '66 Mustang 289. Opened the hood at night with the engine running and I had my own little light show display with all the arcing going on.
One other point--are your plugs and wires matched?--or is it possible you have resistor plugs along with resistor wires? It should be one or the other. -- Dave

Hi guys,

Thanks for all the suggestions and the clarification on why it's starting with a bump. Maybe as the next step, a new cap and wires for the distributor.

Much obliged,
F.Ramp

Floyd;

Not being able to Start normally, and only by bump-Starting (when damp) suggests something is marginal in the Ignition System...the engine is only able to sustain running when the significantly more energetic bump-Start technique is used...I'd suspect HV system...start by cleaning carbon dust from underside of Dist Cap and Rotor...these can give conductive paths for HV to leak away when damp and fine condensation droplets occur...and since this would be occurring under the dist cap, would not be visible by an under-hood inspection.

I know you said you checked for HV leakage, but sometimes its subtle and not easily seen...its therefore good practice to also preventatively clean all external HV areas from Coil to Dist, to Spark-plug squeeky clean with carbcleaner as a periodic general maintenance.

COG;

Having connections clean and snug is good general advice, but it's not possible to "Verify voltage to coil" because remember, that node is strictly internal to the Ignition Switch/Armored Cable/Coil Assembly and just not available...

Good Hunting!