Cold Start

[scoutpilot]

Yes.

[GunnersWillys]

Well, back again, same basic issue, no spark.

I haven't started it in 3 - 4 months, busy elsewhere, but when I put it away last time I could not get it to start a few days later.  Decided to get after it this weekend.  Here's where I am after using resources in tech tips.

- Key on, using a 12 volt test lamp grounded to the battery we are hot from switch to + terminal at the coil, strong light. 

- Key on, coil negative terminal where wire leaves for distributor, hot when key on, bright light, no light with key off.

- I also checked the same circuit inside the distributor to see if it was hot at the connection to the condenser.  It was.  I replace and double insulated that wire a while back to insure it was not grounding out as it passed thought the distributor wall.

- Points:  Strong spark, key on, open points with a stick.

- Coil Spark Plug Wire to Distributor:  Pulled distributor end of the wire and held it near the engine, key on, opened points, strong spark.

- Coil: Very new, replaced last round when this happened before.

- Distributor Cap:  Pretty new, looks fine.

- Rotor:  Pretty new, looks fine.

- Timing light to check for spark on plugs while turning over:  Nothing (did get one flash that stopped after the first flash).  Also, I should be able to attach that to the wire from coil to distributor and see spark.  Nothing.

- Condenser:  Pretty new, but I swapped it out for an old one just to see what happened.  Nothing.

I'm not ruling out the condenser as I don't see what else it could be.  I just hate throwing parts at things.  I can pick up a new one if you think it might help.

Thoughts?  Thanks.

[Rus Curtis]

Good tests.  I would repeat your test that was performed on the coil to distributor wire (held against engine, observed spark) with each spark plug wire.  Each leg of the spark delivery should give you the same spark show you did manually using a stick.  Have you tried this test while cranking the engine? 

I didn't see any assessment on the spark plugs themselves.  If other components were, "very new," I would guess the spark plugs are too.  How about the wires? 

 

[GunnersWillys]

Rus:

Plugs, as you expected, are pretty new.  I have not pulled plugs and checked for spark by holding close to ground.  I'm not seeing any indication of spark on the timing light so I didn't see much point.  I suppose I could.  Can't hurt.

Plug wires are also pretty new.

The coil "plug" wire carries spark to ground in a static test, but doesn't seem to do so when turning over the engine.  It's just me doing the tests.  Maybe I'll enlist some help tomorrow evening and see if the coil wire fires a spark to ground while turning the engine over, same with the plugs.  But a spark should show up on the timing light.

My local FLAPS didn't have a condenser.

One more thought.  I've coated the spark wire ends with dielectric grease.  The intent is to keep out moisture.  Any chance this could inhibit spark?  A quick Google indicates it is possible if you get carried away.  I'll clean it out a bit and see if that helps.

[Rus Curtis]

These ideas are an attempt to move "down stream" from your verifying that the coil is sending spark.  Need to find where that's breaking down now.

Not being an electrician, It's my understanding that while a timing light has clips for the battery for power, the large loop clip (inductive clamp), that goes around the wire senses the pulse through the wire.  So, assuming the light isn't malfunctioning (it could be) the lack of a light from the timing light means the wire isn't transmitting the spark to the plug.  Also inspect that spring tab in the middle of the distributor cap that contacts the rotor.  Hopefully, it's got some good spring and travel to it.

The timing light could also measure the other wires, i.e. blinking light in sync with the spark of that wire but no relation to the timing as that's tied to #1.

Something simple (and really annoying), could be an ill-fitting cable end - either at the distributor cap or the spark plug.  Are the wires copper/metal core or the suppression style?

[GunnersWillys]

Well, it's running!

Rookie mistake.  I never stop making those.  It most definitely was too much dielectric grease. 

I first cleaned the coil wire both ends and the female receptacles on the coil and distributor cap using a stick, paper towels and contact cleaner.  I then had intermittent spark with the test light on the coil wire.  No spark at the plug wires.  Then the same process on the plug wires at the distributor cap, and got intermittent spark on the plug wires.  Used some starting fluid (I hate doing that) to give it a boost, and after a few minutes she fired up and purred.

I was immediately reminded that I need to change the head gasket.  Water vapor out of the tailpipe looks like a fog machine.  I have the gasket, have just been putting it off. 

Thanks everyone.

Richard

[Rus Curtis]

dielectric is one of my favorite add-ons.  This is good to know.  Glad you got it running!!

Now on to the next issue!