Topic: '66 289 C code, C4 ignition coil voltage

[socalgt]

Unable to start engine after confirming #1TDC, correct firing order, new points, condenser, cap and rotor...verified fuel delivery, points sparking as well as plugs.  Believe it to be an electrical issue for sure.  I have about 6 volts to the coil with the key in the on position and assume it will allow the full 12 in the start position.  Do I understand that correctly?  I will check for 12 volts at  the coil during start attempts.  Engine is definitely getting fuel.  Plugs check for spark, although weak, as well.  Distributor has not been moved or removed since it was starting and running with no problems.....it just began to not start.


Running out of things to check...….Thanks in advance.           I know.....spark and gas is all it takes, but...looking for suggestions.

Timing is set properly
verified #1 tdc compression stroke with rotor pointing at #1
wires in proper order accelerator pump is operating

[midlife]

Hook the battery directly to the + side of the coil and see if the engine starts.  Don't leave it attached with the engine not running for very long, as it will burn up the points.  You should have more than 6V at the + side of the coil, but most measurements are taken with the engine running, and the average is 10.5-11.5V. 

[mgmradio]

Incorrect Mid. There should be 6v to the coil in the run position and 12 v in start. Make sure that your point gap/dwell is correct on the points. Condenser could be bad also.

[sgl66]

Unable to start engine after confirming #1TDC, correct firing order, new points, condenser, cap and rotor...verified fuel delivery, points sparking as well as plugs.  Believe it to be an electrical issue for sure.  I have about 6 volts to the coil with the key in the on position and assume it will allow the full 12 in the start position.  Do I understand that correctly?  I will check for 12 volts at  the coil during start attempts.  Engine is definitely getting fuel.  Plugs check for spark, although weak, as well.  Distributor has not been moved or removed since it was starting and running with no problems.....it just began to not start.


Running out of things to check...….Thanks in advance.           I know.....spark and gas is all it takes, but...looking for suggestions.

Timing is set properly
verified #1 tdc compression stroke with rotor pointing at #1
wires in proper order accelerator pump is operating

Have you tried starter fluid to see if it at least tries to run?

Are you using one of those failure prone repo coils?

[Hipo giddyup]

How did you check TDC?? With a cylinder whistle? Just a screwdriver testing for the top of the piston??

Reason why I'm asking is because I have a TDC tool with the whistle that sounds as the pressure is built up in the cylinder (compression stroke). Funny thing is that it also makes a "similar" sounding whistle while on the exhaust stroke. LOL I learned that one quick.

[67gta289]

The phrase "timing is everything" comes to mind in a situation like this.

[socalgt]

Thanks for all the replies..

New distributor cap
New rotor
New condenser
New points
New Autolite 45 plugs with correct gap
Verified #1 top dead center on compression stroke both by pressure and position in cylinder...rotor pointing at master cylinder(#1 plug wire position)
Tried direct wire from battery to coil....very short time...still no starting, or even trying
Tried starter fluid...no attempt to fire up
Verified correct plug wire placement on cap
New coil
(distributor has not been removed or position changed since car was running)

Pretty much running out of ideas, unfortunately...I have an electronic ignition system(the one that just replaces the points) to install, but I don't know why replacing the points would help, since the points are producing good spark and are gapped correctly.... but I might as well try.

[sgl66]

Although you have a new coil, I would still be suspicious. If it were me, I would find a known working coil and swap it in to see if that solves it. The repo yellow top coils are notorious for having issues, I have 2 brand new ones sitting on a shelf that don’t work. The problem is the coil windings inside short and although it may throw a spark, it is too weak to ignite the fuel mixture. Off the top of my head, I believe the coil should send out ~25k volts.

If it turns out to be the coil, you can still find original Ford units on Ebay which don’t suffer from the issues that repo untins do

[Brian Conway]

Simple field test.  Audible snapping blue spark indicates good points, coil and spark.  Yellow indicates not so good and where to start looking.  Brian

[Bossbill]

Make sure ground strap inside of distributor is properly attached.
Put old condenser back in.

Make sure engine is not cranking much faster than before which would indicate loss of compression due to cylinders being washed down with gas or loss of compression due to timing gear having jumped. Almost all timing gear issues occur during engine shutdown.
A compression test would be in order.

[socalgt]

With cap removed good spark is visible at points when cranking engine.  When I connect a plug directly to the coil wire the plug sparks no problem.  When I connect the plug to its' distributor wire and ground the body of the plug the spark is weak.  I cleaned and reconnected the battery ground to the engine.  Just to clarify, the car was running fine and then suddenly would not start....and that's where I currently am.  I have to say, I've never had this much difficulty on a "spark and gas" engine.  The "snapping noise" is only present at the points with the cap off when the engine is cranked.  Please keep the suggestions coming....I'm pretty much out of ideas.....the only thing I haven't done is replace the plug wires, which look fairly new and in good condition.

Thanks!

[Brian Conway]

Replace the points and rotor or just reinstall all the old ' working ' components  Brian

[gjz30075]

"unable to start the engine...."    What was done just before this?     I 'ass-u-me-' your post with verification checkpoints are just covering the
'won't start' situation?    ie, has this engine run before?

[OldGuy]

Make sure ground strap inside of distributor is properly attached.
Put old condenser back in.

Make sure engine is not cranking much faster than before which would indicate loss of compression due to cylinders being washed down with gas or loss of compression due to timing gear having jumped. Almost all timing gear issues occur during engine shutdown.
A compression test would be in order.

+1  How many miles are on your engine? Has the original nylon/aluminum cam gear ever been changed? These things are notorious for jumping time due to worn/broken teeth on the cam gear coupled with a worn/stretched timing chain. Check to see that the distributer rotor is pointed at number 1 when the timing mark is at zero (yes it could be pointing at number 6 if you are 180° out). This is assuming that you haven't moved the distributor position to MAKE it point at number 1. Do this step before you change anything else electrical. I would have thought that you would have discovered the problem (if it was electrical) by doing all that you have done. Engines generally do not fail to start (if they have been running reasonably well). They may run progressively worse until such time that they will not start but you would have known if this was the case.

Frank

[socalgt]

The distributor is undisturbed since it ran.  Rotor is pointing at the number plug wire with timing mark on TDC, verified on the compression stroke.  105K on the engine.  Coil voltage about 6.5 volts with key "on", increases to almost 12 when cranking with the key.  My understanding is the path sequence is the points open, allowing high voltage from the coil to the rotor, then to each plug wire with its' rotation.  The points are correctly gapped and have a strong spark.  Switched coils with my other '66 in good running condition, no difference.  I will measure and confirm the rotor is contacting the distributor cap correctly.  Back at it today, although I'm not sure what more I can experiment with.

Thanks again for the replies...