#1  
Old 05-13-2020, 03:30 PM
bluejudge bluejudge is offline
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Default 69 GTO WON’T RUN

The car turns over like it wants to run, but as soon as I let up on the key it dies out. It was getting hard to start in the past, then I went to take it out one day and it stalled out. Sounded like it ran out of gas. The needle reads half a tank, but just to make sure I put 2 more gallons in. I had the carb rebuilt, and put a new fuel pump in. I have spark, but I just changed out the breaker less ignition, and put the points back in to make sure and IT STILL WON’T START. Is it possible it is the ignition switch, that is my last guess. Thanks, Marc

  #2  
Old 05-13-2020, 05:27 PM
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Could be a ton of things. People are going to want some background.

How many miles on it, what modifications, when did it last run etc.

Did you try any dry gas in the tank in case it has water in the fuel?

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Old 05-13-2020, 06:21 PM
PontiacJim1959 PontiacJim1959 is offline
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Since you said it sounds like it almost wants to start, I assume the engine is catching, but just not firing up?

Things to check:

A bad ignition switch will do it. Run a 12V hot wire from the battery to the +positive side of the coil. Crank the engine and see if it fires when you let the key snap back to the run position. If the engine fires up, I would change out the ignition switch just to eliminate it as the problem rather than begin to trace wiring. If the new switch did not cure it, then I would start the wire search looking for a problem. The ignition switches do wear out and I have had a couple go, so with these older cars, it won't hurt to swap in a new one.

You could test the power at the coil which would be a quick check before swapping ignition switches. You should have 12V with the key in the start position while cranking. In the "Run" position, the resistor wire takes over and you should have about 7ish volts or you can damage/burn out the points. Now if you already upgraded your ignition/coil wire to 12V for the electronic conversion, you will have 12V for both start/run. Don't know what you did when you upgraded to the electronic conversion or when you went back to points.

1.) Choke not opening as it should - too tight not allowing air in.
2.) Good clean air cleaner filter? These can get clogged up and choke off the inlet air to the carb.
3.) Incorrect timing setting. The balancer, if original, could have slipped and you are trying to time it using the balancer mark - which will be off.
4.) Coil going bad. You have a spark, but not a good one.
5.) Coil wire. I have had these go bad. They typically just quit, but installing a new one eliminates one more thing.
6.) Timing chain/gears worn/sloppy. If original set, nylon gear on the cam and anything after 60,000 miles typically means you are on borrowed time - unless you never stomped on the engine as did the previous owner and drove it like a little old lady.

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Old 05-13-2020, 06:43 PM
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Thanks dataway and Pontiac Jim. The motor was rebuilt a while ago, about 5000 miles on it. It’s stock except for the breaker less ignition and accel coil. I will check the ignition switch next. The engine is catching but not firing up. Right now I have no air filter on it. The choke looks fine. I did not touch the timing until it did not start and looks fine. I tried another coil and still nothing. I did not try another coil wire. I can do that so I will try that too since it will take 5 minutes. Thanks for helping out. Marc

  #5  
Old 05-13-2020, 07:34 PM
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If memory serves, they used a resistance wire to coil for run, which would drop voltage a little to keep from frying the points. While cranking, 12V would be supplied to coil, then when releasing key to "run", the resistance wire would provide running voltage. If it's open, jumping battery + to coil + would jump around it. Sounds like either switch or wire...?

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  #6  
Old 05-14-2020, 02:24 AM
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Yeah, it definitely has the classic '12 volts in 'start' position but 0 volts in 'run'' position symptoms.
Tries to start as long as you are holding the key in the 'start' position but loses the ignition voltage as soon as you release the key to the 'run' position.

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Old 05-14-2020, 02:46 PM
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Thanks everyone. One little wire from the battery to the coil and she started right up. And another call to our host for an ignition switch. Maybe I’ll check some wires first, but probably not. Thanks, Marc.

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Old 05-14-2020, 04:34 PM
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You might want to check the specs on the breakerless ignition for voltage requirements. If you change the switch and IT WAS the problem, you're still supplying lower than system voltage through a resistance wire in "run", which could have an adverse effect on performance.

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  #9  
Old 05-14-2020, 06:59 PM
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I’m glad the car stalled out in my driveway. Can you drive the car with the wire connected to the battery and the coil, just in case you are out somewhere. I was taking the out for a ride but never made it out of my driveway. Thanks, Marc.

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Old 05-14-2020, 08:34 PM
PontiacJim1959 PontiacJim1959 is offline
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Yep, you could drive it. Just have to pull the wire off the coil to stop it, and/or turn the ignition off if it continues to run.

You now know how easy it is to steal one of these cars. Hot wire to the coil, jump the starter solenoid-to-battery post on the starter with a long bladed screw driver and ............. Never stole a car, but have had wiring issues on these old cars back in my youth and learned a few tricks.

The locking steering wheel/key and back drive was designed to make it less easy to steal these cars. The older Fords are even easier to jump with their remote starter solenoids. Comes in handy when you lose the keys on a 1968 Ford pick-up. LOL

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Old 05-14-2020, 08:53 PM
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You can run the car with a jumper connected, if you have points it will eventually burn the contacts in the points. If you've done a conversion you probably won't have to worry about the jumper hurting anything.

FWIW, I bought a 1970 Judge in 1975, and the owner had a toggle switch wired into the ignition system because the ignition switch had already went bad at about 50,000 miles, pretty common problem.

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Old 05-15-2020, 05:53 AM
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I’m going to put back my breaker less ignition, now that I know it’s not that. I am going to make something up for a jumper and keep it in the trunk just in case...

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Old 05-15-2020, 10:14 PM
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Sirrotica, I really can’t complain. The part is over 50 years old!!!

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Old 05-19-2020, 10:51 AM
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My 69 GTO did this in 1975 at 151,000 miles........it was the resistance wire
burned out in the wiring harness. On these cars the resistance wire runs from
the bulkhead connector at the firewall to the ignition coil. The wire on the inside
of the car going to the bulkhead connector is regular heavy gauge wire.

  #15  
Old 06-07-2020, 07:08 PM
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So I got around to changing the ignition switch today, went to go start it up and the same thing. It won’t start. I did notice 2 wires connected to the switch was butt spliced, so now I have to get back under there and check the wires. I did start it back up with the jumper wire from the battery to the plus side of coil again to pull it back in the garage, however the clip fell of the coil onto the valve cover and burnt the jumper wire up. The wire is 14 gauge, what size fuse should I put in there so that don’t happen again? Thanks, Marc

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Old 06-07-2020, 07:53 PM
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You probably have the typical wiring failures due to people cutting and splicing wires over the years under the dash/hood. The other problem is degradation of wiring, connectors, and switches from 50 years of corrosion, and deterioration, not to mention possible rodent damage.

Some of the wiring I've seen is downright scary in old cars, wiring splices with wire nuts and speaker wire. Wires twisted together with no insulation, and a whole lot of other stuff that is both inefficient, and dangerous.

A 10 amp fuse should be sufficient to fuse your jumper wire.

The wire on the starter solenoid that feeds the distributor during cranking could be disconnected or broken, I believe it's coded I on the solenoid terminal, yellow wire, maybe?? (going from memory here). It feeds 12 volts during cranking to give the engine a hotter spark, rather than the resisted down to 7 volts run voltage that comes through the switch. If the switch was defective you should be able to remove the jumper wire after it starts and still run the engine. If it dies the problem is in the wiring or connections.

Lots of possibilities for bad wiring or possible incorrect wiring.

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Old 06-07-2020, 08:05 PM
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What's the voltage at the distributor when the switch in the on position and what is it while cranking the starter motor?

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Old 06-07-2020, 09:21 PM
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Quote:
Originally Posted by Greg Reid View Post
What's the voltage at the distributor when the switch in the on position and what is it while cranking the starter motor?

Sent from my moto g(6) play using Tapatalk
It will be battery voltage which should be 12 volts. Once it fires up and you let the key snap back to the "RUN" position, that is when the resistor wire takes over to drop voltage down to around 7ish volts so as not to burn up the points if you still have your points distributor hooked up.

You should see 2 wires going to the coil and usually jointed together at the end where the connector goes to the coil stud. One will be 12volt, the other the resistor wire.

If an HEI or electronic ignition has ever been used, then you want 12volts, period, no resistor wire used. So this means you have to eliminate the resistor wire and replace it with a "standard" wire or find a 12V source that becomes live with the key on to provide 12V when the key is snapped back to the "RUN" position.

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Old 06-07-2020, 10:14 PM
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Yes, that's what I'm trying to get established...that whatever the run and start voltages are, they need to be supplied in both key positions

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  #20  
Old 06-13-2020, 02:37 PM
bluejudge bluejudge is offline
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So I checked the wire under the dash going to the ignition switch. The yellow wire that goes from the ignition switch to the coil was not the wire that was spliced and it has continuity. Next is what PontiacJim and Greg suggests. The two wires that are spliced are the ones next to the yellow wire they are Pink and Grey, I am going to check them too for continuity. Thanks, Marc.

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