It has been some time since I posted because… she has been running flawlessly to date
I’ve already had one long drive (20 miles+) this season w/ no issues. Yesterday after filling her up from my usual non-ethanol station the engine died about 10 miles post fill up. The engine would still turn over but would not fire.
My assumption was that there was something wrong with the fuel pump/fuel system (I have had to replace the fuel pump before, and clean out the fuel lines) however today when I pulled the fuel system apart I can verify that I have fuel all the way to the carbs.
With the ignition on the car turns over strongly however there is no ‘catch’ at all - no indication of spark firing.
The odd symptom is “shudder” that occurs right after I turn off the ignition after a few unsuccessful engine cranks. I have no idea if this is normal or could be related to the engine not starting.
First determine if you have spark, if not the issue, then look at fuel (which you said you already have). Hard to think of something blocking air all of a sudden.
The ‘shudder’ at end of crank tends to be indicative of an electrical/timing issue. How does the distributor and rotor look? If you are on points, has the point gap closed due to a loose screw? Has the distributor moved (loose clamp)?
no obvious sign of anything moving or loose - i’m waiting for my 10 year old son to come home from school to hit the starter motor while I look for a spark on the plug that I’ve pulled.
Since the engine went from running perfectly to shut down it must have been something catastrophic/sudden - the only thing I’ve read that makes sense is the coil failure - which is good news since fairly cheap and easy to replace…
Isn’t there a vacuum assist that would build from engine turning and would be “released” when I shut off the ignition? Wondering if that is that I’m hearing/feeling when turning off the ignition. Probably unrelated to engine not working.
If you are still using points in your distributor, and the points are opening and the gap looks good, then replace the condenser and rotor. I once had a condenser go bad and have also had a rotor go bad. It acted kind of like what you describe.
no spark…
This is the coil I believe… but no sign of a condenser?
I’m inclined to replace the coil - easy to do and relatively inexpensive - plus it won’t require me to pull apart the distributor. I’m still thinking that this is the most likely culprit as it was a sudden and catastrophic fail?
Not normally a fan of throwing parts at a problem but since everyone should have (and carry) a good spare coil you will not be too bad off if it doesn’t fix the issue.
The condenser is inside the distributor of course and there is no reason to hesitate opening it up (just two clips) and visually inspecting the points gap, etc.
I definitely need to build my spare parts kit… After learning the hard way I now carry a complete set of banjo connector fibre gaskets and large wrench to tighten plus safety reflectors and a work light. I’ll add the coil to the list.
I would suggest that before you buy a coil, you test for actual spark while cranking. This involves taking a spark plug lead off, stuffing a philips screwdriver into the cap’s part that clips onto the spark plug, holding the metal part of the screwdriver about 2 or 3 mm from metal ground, like the cam cover, and asking someone to crank the engine while you look for sparks jumping the gap between metal screwdriver and the ground that is 2mm away from it.
If I understand that you have a '67 are the ignition switches on them heavily loaded and can be problematic with age like they are on the '68s ? Several years ago my ignition switch would get quite warm and sometimes do a shudder right after I turned off the ignition. Later on it fried when I was at the back of the car checking things for vapor lock and a no-start problem after a run on a hot day. I did not have to do any checks to know then that I had a failed ignition switch but I have heard other folks tell how old ignition switches can develop inhibited contacts. Just a thought.
Go to your FLAPS and buy an inline spark tester. Put it between the coil and the distributor lead, or a plug and its lead. Confirm that you have no spark. If so, follow the algorithm below…
Symptom: car won’t start or run at all.
NOTE: assumes NEGATIVE earth, points in distributor.
To Confirm: Put a plug tester in series with a plug. It should flash when engine is cranked. If no flash check other plug leads as well. No flash = no spark.
If you do have a flash the problem is NOT spark per se, although it MAY be plugs. See 9.
Otherwise the problem may be timing, or fuel or compression. These steps will not help those things.
Take each step one at a time, in order. At the end of each step try to start the car.
Battery flat.
If the car cranks over it is almost certainly OK.
Engine earth.
Spark requires a good earth to the negative terminal of the battery. Check that the engine is earthed with an ohmmeter or voltmeter between the battery and the block.
Visually inspect the engine earth lead (LHS behind the reaction tie plate. If in doubt run a thick cable (jumper lead) from the battery negative terminal to the engine.
Check power to coil.
Remove the positive connector to the coil. Put a 12v test light in series and turn on the ignition. The light should come on and be steady.
Jiggle ignition key to eliminate switch fault.
If no power, run a wire directly from the positive battery terminal to the positive coil terminal and try ignition. If it works problem is between battery and positive terminal wire. Check fuse 7 and chase wiring with multimeter. Recheck ignition switch. NB starter button will not affect spark.
Check points are opening and distributor is turning.
You can do this visually. Remove dizzy cap and get someone to crank the engine. You should see the points open and close. Use a torch; it’s dark down there.
Put a 12v test light between the negative coil terminal and the black/white wire to the distributor. Crank the engine. The light should flash off and on as the points open and close. This should work with electronic ignition modules as well because what you are testing is the circuit through the points (mechanical or electronic) to earth.
Note: the light may stay on or off when not cranking depending on whether the points stop closed (likely) or open (unlikely). This isn’t important.
Check the points gap (14 to 16 thou) and inspect the electrode faces for pitting. If any doubt replace points and reset gap. Even when you’re sure it’s not the points, suspect them. It’s always the points.
Condenser.
A dead condenser looks just like a good condenser. Just replace it. They can be tested with an ohmmeter but if you put a new one in and it doesn’t fix the problem it probably isn’t the condenser.
Check the coil.
If the points are working and the condenser is OK. Get a spark plug and a plug lead. Connect the plug lead into the HT coil connector. Earth the plug by resting it next to a head nut. Turn on the ignition. Use a nonconductive (plastic) tool and open and close the points manually. (Alternatively you can connect a wire to the negative LV connector and tap this on an earth.) There should be a spark on the plug each time the points open. If you have spark the coil is OK. Move on to 6.
If NO spark AND you are happy with 1-4 above, the coil may be faulty. Check the resistance of the low voltage (primary) circuit by connecting an ohmmeter to the two LV terminals. This should be between 0.5 (low resistance/sports coil) and 3.5 ohm (standard coil). Check the HT (secondary) circuit resistance by measuring between either LV terminal and the centre HT terminal. This should be in of the order of 5000 to 15000 ohm. Note that coil failure can be exacerbated by heat so even if it checks out cold it may be faulty hot.
Replace the coil anyway with a known good one. (You can just sit one next to the old one and connect the 3 wires to it).
Leads
Remove the coil HT lead. Inspect for cracking or corrosion. Coolant can leak from the thermostat housing down onto the top of the cap and cause corrosion, especially with “screw in” contacts.
Check resistance with ohmmeter; it should be virtually zero with copper core wires.
Check the resistance of each of the plug leads by removing the plug cap and using a multimeter between the end of the wire and the corresponding contact inside the distributor cap. With copper core wire it should be virtually zero. If not check the cap socket for corrosion.
Modern cable resistance is more complex and you would need to check the figures with the manufacturer. As a general guide though a lead should be between 2000 and 8000 ohm.
Plug caps
The original plug caps have a carbon resistor in them. They will have a resistance somewhere between 5000 and 15000 ohm. Modern or reproduction caps should be spot on 5000 ohm. If you suspect the caps, replace or eliminate them. You can solder a ring connector onto a fine 1” self-tapping screw. Screw this into the lead in place of the plug cap. Use the ring connector to connect directly to the threaded end on the spark plug.
Spark plugs.
Remove the plugs. Check for fouling and check gaps. If no success, replace with new plugs.
Distributor cap
Inspect for cracks or corrosion. The cap really should look brand new inside. Clean up the lead connector sockets if at all corroded. The central contact for the rotor button should have a resistance of the order of 30000 ohm. If the cap looks OK still try replacing it with another one, or a known good cap and set of leads.
Rotor button
Inspect and replace if it looks worn, pitted, burnt or otherwise faulty. Try another one anyway if it looks OK.
Distributor
Remove the distributor and carefully inspect it. Ensure that it wired correctly. Specifically check the insulators between the points and the coil and capacitor leads are in the correct place.
Check that that the coil lead is connected and conducts to the capacitor lead.
Check that the internal earth lead is connected to the distributor body and the centre plate.
Check that the distributor turns freely and is mechanically intact.
Check that there are no small screws or other foreign parts loose inside or causing a short.
Other things
If you have got here and not fixed the problem.
The checklist above is fairly complete. Sometimes though electrical components can look OK but be faulty. Replacing each component, one at a time, with a known good (not necessarily new) component will sometimes smoke out a mystery.
what i did to test for spark was ground out the plug when removed from the cylinder head, have my son crank the car for a second and look for a spark in a darkened environment.
No spark - assuming this would produce a spark if there was one…
I have not checked power to coil - thank you for the orderly suggestions!
Take lead from coil to distributor.
Pull it out of distributor and check for spark the same as before when cranking by putting it near to ground.
We are getting close!
Dennis
I have power to the coil and when tested w/ ohm meter I get 2.8 and 8950 ohms respectively - assuming that this is the best and only diagnostic for the coil it seems like the coil is not the problem
The coil has two wires connected to the + side and one to the - side. The red wire is not powered when ignition is on, the brown side is.
Why are there two sources of power to the coil? Does one light up an instrument panel light (seems possible from wiring diagram).
Bill, where are you? I’ll come by if it gets me out of lawn work!
Time to check distributor cap, rotor and point. Look for looseness and brokenness and points gap.
Next a jumper wire, to test the circuit for the coil. One at a time minus the ground, the plus to battery plus assuming you have negative ground. Attach the jumper and see if it starts.
It appears you may have an electronic module. Not points. The brown wire appears to be the 12+ feed. The red probably goes to the module in the distributor. Remove the distributor cap and see what you have.
Tom
