Starting puzzle
- Thread starter 46HARLEY
- Start date
hueyhoolihan
Well-known member
i the OP's "engine cranks fine" is true and i usually assume an OP is giving accurate information. i don't think i'd suspect the bendix or a weak battery.
i think i'd check for spark as i cranked, as a loose wire could be the culprit and popping the clutch just might do the trick. a simple engine bay starter button is a very useful tool to have when working on these old cars. one wire on the solenoid and one on the battery and you control the starter while looking directly at a plug wire is a good way to check for spark. of course if a helper is handy...
i used mine just the other day, when after installing a new condenser the car wouldn't start. i suspected i wasn't getting spark, so hooked up my starter button, pulled a wire and. presto!, discovered i was right...i wasn't getting any spark. it didn't take me long to find that i forgot to to attach the low tension coil wire to the distributors condenser stud.
i think i'd check for spark as i cranked, as a loose wire could be the culprit and popping the clutch just might do the trick. a simple engine bay starter button is a very useful tool to have when working on these old cars. one wire on the solenoid and one on the battery and you control the starter while looking directly at a plug wire is a good way to check for spark. of course if a helper is handy...
i used mine just the other day, when after installing a new condenser the car wouldn't start. i suspected i wasn't getting spark, so hooked up my starter button, pulled a wire and. presto!, discovered i was right...i wasn't getting any spark. it didn't take me long to find that i forgot to to attach the low tension coil wire to the distributors condenser stud.
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hueyhoolihan
Well-known member
i agree...
so one would suspect an electrical problem involving spark. which under the circumstances could be something as simple as a loose wire, as i pointed out. and popping the clutch involves violent movement of the car. possibly enough to make a weak/loose connection connect long enough and well enough to start the car. and the first step, for me anyway, would be to verify there there is no spark when cranking the car. and if none, then starting checking for loose wires, probably involving the distributor and coil and condenser and grounds, etc. and i suspect the OP knows this and probably fully capable of finding a solution to the problem. and the thread is somewhat of a, as indicated by the title, a puzzle or brain teaser (a legitimate reason to create a thread, IMO) and so speculation and random musings are the name of the game with this one.
IOW, i suspect the fact that the car starts (and we were not given information as to whether it repeatedly displays the same symptoms time after time.) when push started is a red herring of sorts, possibly created by an odd set of circumstances.
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46HARLEY
Member
Have not gotten back to the car yet. Car is original except for electric fuel pump. This has occurred the last four times I tried starting it. Prior to bump start I tried gas directly in carb, to no avail. I am leaning towards electrical, but still makes no sense why this occurs. Battery and starter are in good shape. Will start with wiring ? Thanks Larry
Gregoryp01
Junior Member
Sounds like a bad ignition switch, or a ballast resistor. Although if it was a bad ballast resistor it would fire up and shut off when you let off the starter button. Leads me to key switch supplying power to starter solenoid but not to the ignition coil.
ford38v8
Well-known member
So many theories.
Larry, you haven't enough voltage reaching your coil to produce a spark due to the load required by the starter motor. The single cause that accounts for 80% of this outcome is poor electrical connections.
Obtain a voltmeter, and, starting at the battery, verify battery voltage drop to be insignificant at every connection from battery to coil, for a total drop of less than half a volt. To get a proper reading here, the points must be open. If the points are closed, your reading will include the (approximate) 2 volt drop provided by the ballast resistor, and your reading will not be conclusive. To open the points, simply jog the engine over a few degrees, you'll see the meter register open points.
When you discover the major voltage drop cause, clean and retighten that connection using dielectric grease. You can bypass all the diagnostics if you simply do this to every connection.
Importantly, all your wiring and battery cables are correct and in good condition, right? 12 volt cables instead of 6 volt cables are a major cause right there. Your battery and starter motor cables must be sized right, clean, and tight.
Remember I said 80%? The other 20% are: Starter motor brushes 10%, and all the other theories account for the remaining 10%.
Larry, you haven't enough voltage reaching your coil to produce a spark due to the load required by the starter motor. The single cause that accounts for 80% of this outcome is poor electrical connections.
Obtain a voltmeter, and, starting at the battery, verify battery voltage drop to be insignificant at every connection from battery to coil, for a total drop of less than half a volt. To get a proper reading here, the points must be open. If the points are closed, your reading will include the (approximate) 2 volt drop provided by the ballast resistor, and your reading will not be conclusive. To open the points, simply jog the engine over a few degrees, you'll see the meter register open points.
When you discover the major voltage drop cause, clean and retighten that connection using dielectric grease. You can bypass all the diagnostics if you simply do this to every connection.
Importantly, all your wiring and battery cables are correct and in good condition, right? 12 volt cables instead of 6 volt cables are a major cause right there. Your battery and starter motor cables must be sized right, clean, and tight.
Remember I said 80%? The other 20% are: Starter motor brushes 10%, and all the other theories account for the remaining 10%.
petehoovie
Well-known member
JayChicago
Well-known member
That is not correct. Points open, no current flow. No current flow, no voltage drop thru any resistance. You will see full battery voltage at every point.
Voltage drop test must be done with the circuit active.
ford38v8
Well-known member
I said TO the coil, not THROUGH the coil, jumping to ground. Closed points will confound the test. Backtrack to each connection to determine where poor connections cause the resistance.
ford38v8
Well-known member
This is a good fix for this common issue. Importantly, to be temporary, only while cranking with the starter. Of the several ways to do it, the simplest is to bridge the resistor with a normally open toggle switch under the dashboard.
46HARLEY
Member
Bump start and into the garage, battery on full charge. No start, cleaned battery terminals. They were fine. Checked ground on body and engine, no start cranking just fine. On to the starter, tight connection but looks sketchy. Cleaned connection and it started instantly. Confused me how it would turn over so well and not start but the draw must have been to much. Thanks for all your input. Did not think it would be that easy. Larry