leif.anderson93

I'm completely perplexed. This might get a bit lengthy...bear with me. My '67 L79 was restored 6 years ago. Completely gone thru mechanically and electrically. Car has been completely and utterly reliable and a joy to drive. I drive this car approximately 5000 miles per year. Starting procedure is quite simple...push the accelerator to the floor to set the choke and fast idle, one more press for a little "go juice", turn the key on and she instantly fires off...every single time. So far, so good. This past week the weather has been beautiful here in the DFW area, so naturally, the '67 has been out for daily, one hour drives. Monday great day. Tuesday great day. Wednesday car turns over but doesn't want to start. Another squirt of gas, still no go...not even a sputter. Pop the hood, remove the air cleaner lid. Choke is set, Open the baffle and operate the linkage, good solid squirts of gas from both jets. OK, we've got air and gas must be electric. I don't have a remote starter button or anyone around to assist so ...I start to visually check all the wiring. Remove the distributor shielding. All wiring is in "like new" condition, no loose wires, no scuffed or missing insulation...everything looks good, clean and tight. Pull out the multimeter and check the coil primary and secondary...seem to be within spec. Check the ballast resistor...seems to be within spec. Double check all the wiring, scratch my head, go inside and read up on possible scenarios. Thursday, try again. Engine turns over but no ignition. Try a few times...won't start. Wait for the wife to get home so I can have her sit in the car and crank it over while I pull a plug wire and see if I'm getting spark to the plugs. Wife's busy, so put it off until Friday. Friday, I think, what the heck...get in and see if she wants to start today. Fires off instantly. Go for an hours drive. Saturday, another great day...starts right up, go for another hours drive. Now, it's Sunday. Another beautiful day, time for a ride. SOS...cranks but won't start. Go thru the same procedure, can't identify anything wrong, unusual or out of the way. Back inside, read a little more. About an hour later, back in the garage ready to close the hood and decide to give it one more try...fires off instantly. Go for an hours drive.
I'm, obviously, at a loss here and need some fresh ideas. I have a new coil that tests out exactly like the one in the car. Any and all useful tips would be appreciated. Thanks in advance.

MelWff

at any point when it doesnt start did you hook up a dwell meter, did you remove the cap and rotor to check the points to see if they are burnt? Did you check the center wire from the coil to the distributor that the end connectiors are firmly seated in the cap and coil and show no sign of being burnt?

plaidside

So you have an intermittent problem which can be tough to diagnose unless the problem exists.
When it does happen I would put a voltmeter on the posititive side of the coil and see if you have voltage and then when you are cranking the engine.
If no voltage try wiggling the bulkhead connector and then the wires on the back of the ignition switch.
Joe

65GGvert

Measuring the voltage on the coil leads is the way to go when it won't start. See if it has 12v when it is spinning over. If it has voltage in the key on position, but not in the start position, you've lost connection on the wire that goes down to the starter and supplies a full battery voltage when turning over the engine. If you have voltage on the + wire on the coil, read on:
I had the exact symptoms last summer that you are having and after 3 times of happening, I was able to find that the black wire that goes from the neg terminal on the coil to the points plate under the dist cap was loose in the connector at the end where it connected to that neg terminal. It was just a matter of stripping and recrimping the connector onto the wire. Check both ends of that wire to insure a good connection. There are other possibilities, but that seems to be the most common for intermittent no start at all. I am assuming here that you have points and not an electronic ignition of some kind, is my assumption correct?

Nowhere Man

do you have points, or a electronic widget.

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leif.anderson93

Jack and Keith,
I have a widget...should have mentioned that. SE breakerless in place of stock points. The black wire from the negative side of the coil to the distributor plate is clean, tight and in place on both ends.

leif.anderson93

SE breakerless igntion. Coil secondary wire is clean on both ends and pushed firmly into coil and distributor. Thanks.

leif.anderson93

When it cranks over but doesn't start, the starter sounds like it's not spinning at the same RPM as usual...a bit labored. Battery is always on a Battery Minder and is fully charged. The ballast bypass you refer to...is that something other than the ballast resistor on the firewall?

Nowhere Man

I would remove the widget and try points and see if your problem goes away. your problem sounds like a classic electronic ignition failure

leif.anderson93

I had thought of that but assumed if it were to be faulty, it wouldn't be intermittent/or work at all. Certainly an option to be considered. Again...thanks.

65GGvert

I also have SE Breakerless in one of mine. You still need to verify 12v coming up from the starter to the + on the coil when cranking. Without that 12v the car won't start. The ballast is out of the circuit at that point, until you release the key to the run position, then the voltage comes from the ballast (on the firewall). You could also have an intermittent module in the SE system. It's more likely it's a connection issue, but still very possible. You did verify the black wire connection to the SE module, correct? The very first thing you need to start is the voltage coming from the starter to the coil +. Verify that. You can connect a jumper from the + on the battery to the + on the coil and if the car starts, you know that's it. (provided it doesn't start with the jumper disconnected) If you can catch it when it won't start, measure the + coil terminal while cranking and report back here what you find. That will give us a very good starting place.(pun intended)

leif.anderson93

Jack,
This is the route I'm going to start with. The black wire on the SE module is tightly connected and shows no sign of deterioration. Over the next several days if this recurs, I'll check the cranking voltage at the +terminal of the coil and report back. Thanks again.

Frankie the Fink

As 65GGvert said, next time it happens take a jumper wire from the + battery terminal to the + side of the coil,
This eliminates the ballast resistor and some wiring and can cut your troubleshooting in half...

And check that distributor clamp bolt is tight - ask me how I know...

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Nowhere Man

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Nowhere Man

Nowhere Man

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