Hi guys,
I’ve run out of ideas on this one. 1969 GTO 400ci auto trans. and stock ignition. It’s seldom driven and did not fire recently after sitting awhile. It’s a friend’s car. He has a '64 GTO parked next to it and I have been able to swap the ignition parts between the two. I have done this with the rotor & cap, coil and coil wire. I installed new points and condenser. I put a jumper wire from the battery to the + side of the coil. I used a jumper wire to ground the distributor body to the engine in case it had lost the ground. I inspected the wire from the points to the coil and checked resistance with an ohm meter. I have verified that the distributor is turning. Still I have no spark. Obviously I’ve overlooked something…but what? Any ideas appreciated.
When the points close they ground the (-) wire from the coil. When the points open the ground is opened. Using a test light, disconnect the (-) wire from the coil and connect a test light to the wire and connect the test light lead to battery (+). Remove the distributor cap and when the points are open the light should be off and when the points are closed the light should be on. The points had shellac on them and if it was not cleaned off it will act as an insulator.
Well the guy obviously has too many GTOs. Since the 69 isn’t running I would be glad to purchase it from him at a fair discounted price since it isn’t running (it is one of my all time favorite cars) and that should solve his problem.
I like Red Knox’s idea but I think a simpler way to check things is to just place the test light probe on the minus side of the coil connection and then see if the light pulses when the engine is cranked over. If the light just stays lit it means power is getting through the coil but there is a problem with the points connection not making the ground connection for some reason. Possibly the wire between the two is open but you apparently checked that.
Another thing to check is the wires to the points and condensor.
Both mount to the vacuum advance plate, and over time these wires get flexed to where they break inside the wire insulation and can’t be seen. So there’s no spark when the points open.
Are you sure its not getting spark? Are you testing for spark or is the engine just not starting for you? 5’m wondering if you might have a timing issue or a fuel issue.
Before the HEI system came out in 1975, a crappy ignition part known as a “Uniset” came out. This was a points set and condenser mounted as a single unit…They were VERY prone to problems and failures. So if you are using one of those, go back to a separate points set and condenser…Have a dwell meter hooked up when you crank it. It should read around 30 degrees even at cranking speed…If the meter needle does not move, the points are not opening or as Tester pointed out, there is a wiring failure…You set the dwell through that little window in the distributor cap with the engine running…They make a special tool just for that purpose…28-30 degrees…
Thank you gentlemen. Tester I’m glad you are still around here-your advice has always been spot-on. I had disconnected both ends of the wire from the points and pulled it up thru the grommet so I could really get a good look at it; put the ohm meter on the ends and pulled and twisted pretty hard with no change on the meter, but I think I will try running a temporary wire thru the window in the cap and see if that makes any fire.
If a ballest resistor or primary wiring issue was the problem, my jumping right from the battery to the coil should have bypassed that problem.
I took out a uniset and put in a separate condensor.
Not only has there been no hint of ignition while cranking, but my timing light doesn’t fire on any cylinder or coil wires. Cranking sounds normal.
Are you setting the points correctly? Turn the engine until the points rub block is resting on a high point on the cam. Then adjust the gap between the points to about .016". Then hook up the dwell meter and adjust per Caddyman’s recommendations.
If you don’t have a dwell meter, then the 0.016" gap should be OK. If you are unsure of the timing, after you get the points set, turn the engine to 4°BTDC for the number one cylinder. If you have the valve covers off, both valves for #1 will be closed while the exhaust valve for #6 (if I remember the firing order correctly) should be closing and intake opening.
You can also use the “feel for compression” method, by removing the #1 plug and sticking you thumb over the spark plug hole and crank till you feel pressure building up, then slowly turn the engine to 4°BTDC. Then loosen the distributor holddown.
Then with the ignition switch on, the rotor should be pointing to the spot where the #1 plug wire would be if the cap was on, slowly turn the distributor to close the points (backwards), the toward opening them. Stop when you see a little arc across the points. Tighten down the distributor, start the engine and confirm the timing.
One more thing, if you don’t have a dwell meter, you can use a volt meter. You should get about 6v on the - terminal of the coil while cranking if the points are set right.
No timing light function indicates no spark. Maybe you have 2 bad distributor caps, or a bad coil. If you are sure the points are set right replacing the cap would be my first step at throwing money at parts, replacing the coil second. Can you see if there is spark from the coil wire?
No one has yet mentioned the little thing called a ROTOR…As all of you know there are no real extra parts within a distributor…and the rotor is just as important as all the other parts of the system.
To test the integrity of your timing light…You could always put the pickup lead on a different wire other than #1…put it on ANY other wire (coil or plug)…do you get a light? DOes your T-light even work? Maybe not… At any rate you dont need it until the final tune up to set your ignition timing for proper running…
The quickest and easiest way to see if your coil (ignition system) is generating a spark…
you can pull the cap off the distributor…Also pull the coil wire from off the top of the distributor and have it near a ground point extend it if need be…have the engine in a location where the points are CLOSED… Then with the key ON…manually open and close the points…You should hear or see a spark jumping from the coil wire to ground…You mite need to use a piece of speaker wire to test the integrity of the coil wire that you have. NOW…IF YOU DO…get a spark…then you just found yourself a BAD ROTOR…OR coil wire. The rotor may either be broken…or too short to reach the individual plug terminals within the cap… Unable to distribute the voltage to each plug wire. I know it sounds stupid, but ask me how I know to look for these things…lol
You can also do a visual check by putting the rotor inside the distrib cap and see if she is long enough to be able to reach the individ plug terminals inside the cap…AND OR check the inside of the distrib cap to make SURE that the central spring loaded lead is there number one…and not stuck or pushed in unable to extend down to reach and touch the center of the rotor… If this little “nub” is stuck or missing then the rotor cant distribute the spark voltage out to the individ wires…
Sounds silly I know, but I have fallen victim to ALL OF THESE LITTLE GREMLINS IN THE PAST. Just assuming that all was well inside the cap, without visually checking OR that I had the correct rotor size and type only to find out the hard way, that I DID NOT…SUPER silly but true.
Just a really quick and dirty test you can do for ignition system and your sanity.
You don’t even need to pull the coil wire from the distributor cap to do that test. Just opening the points will make an arc across the points that is visible. If you open the points with your finger, or un-insulated tool, you won’t need to see the spark to know it’s there.
You also need to use a coil designed for this type ignition system, you cannot substitute a modern coil from an electronic system.
True, but I want to see the spark out of the end of that coil wire…It proves out a few other pieces of the system…just for peace of mind… Otherwise you are correct Sir.
Please tell us what happens when you place a test light probe on the minus connection of the coil with all the connections connected as they should be and while cranking the engine. Clip the lead of the test light to ground. Tell us what you observe the light doing while cranking the engine.
Starting and running are two different things. When you twist the key to engage the starter motor, all the accessories are turned off, but the ignition is supposed to be on. If the switch is defective, you may not be getting spark when the starter is cranking the engine.
Connect a volt meter to the - side of the coil and ground. Turn the key on or connect your + jumper. You should see 12V or 0 volts on the meter. Turn the engine over slowly by hand while you watch the meter. As the points open and close, the meter will jump between 12 volts and 0 volts. Do this with the distributor cap off so you can watch the points. 12 volts, points open. Zero volts, points closed…
If you can see the points open and close and the meter (an analog meter works best) stays on zero, the coil primary winding is open or the points are shorted to ground or the condenser is shorted to ground. If the meter stays on 12 volts, the wire connected to the point set is open or the points have no ground…I’m assuming you are using a NEW set of points? Not a “reconditioned” or filed down set…
“Honda Blackbird 5:44PM Report
No one has yet mentioned the little thing called a ROTOR…As all of you know there are no real extra parts within a distributor…and the rotor is just as important as all the other parts of the system.” He had tried a different rotor, and in my experience distributor caps are more prone to failure than rotors.
I hope this isn’t the case for the OP, but when I put new points and condenser in myh first car, a 1947 Pontiac, I didn’t get a spark. After an hour of troubleshooting, checking and rechecking the point gap, I found the problem. I hadn’t put the rotor back in the distributor.
I also once installed new points and condenser in a lawnmower engine and didn’t get a spark. The new condenser was defective. It’s rare, but it happens.