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Discussion Starter #1
After 15 years with no electrical issues, the other day after a long drive, the next day car cranked but would not start. Checked power to distributor, which happens to be the issue. Ran a new 12 gage wire from + to fuss box with a switch and fuse. It starts and runs fine. Question - before I replace the ignition switch, what else does this switch turn on with key in run mode? I assume the fan and gauges. The fan and gauges do come on when key is in run position which tells me ignition switch may be good. Turn signals and tack are the only other issues now not working. I left the original wire to + coil off so that may be the tac issue. Any suggestions?
 

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You really need to have a Chassis manual & wiring diagram if you don't already have one. If I am not mistaken, the coil + wire may run off of the starter solenoid. I know these are wired differently than the earlier 1968 and under which has 2 wires going to the coil + wire.

It is also possible that the neutral safety switch has gone bad OR is out of adjustment. Check all fuses first would be the first thing to do. Try putting the shifter (if automatic) in neutral and see if that works. Wiggle it a bit while trying to crank. My '73 Fury has a start issue in Park, and I have to jiggle it a little to get it where the neutral safety switch on the column will let the car crank.

I am not a '70 expert, but if a 4-speed, the clutch pedal needs to be depressed as it activates a neutral safety switch. You should also have a "back drive" linkage and I believe that if this is out of adjustment, it won't start. Manually twist the steering column collar by hand is what I recall can also be the solution.

It is possible that the key switch is bad as they are old and don't last forever. I would do some wire tracing to see where the power is and where it stops so as to isolate the problem.

(y)
 

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Discussion Starter #3
thanks Jim, its a automatic and was converted to single wire coil (MSD distributor setup) before I acquired the car in 2006. I also have the manual and its shows in run and start key position , a yellow (start) and black/pink (run) wires going from ignition switch to terminal box, then black/pink wire on engine side going to + coil. Since I have no volts in either run or start, I assume its the wire in engine compartment as it most likely was spliced in to replace the resister wire (now just black wire). I'll check the fuses and try putting transmission in neutral and also will check the volts under the dash at the terminal box if possible. Is there a way to check volts without piercing the wires?
 

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The neutral safety switch has nothing to do with ignition; it's only to prevent cranking the car in gear. The ignition circuit is separate from any "accessory" issues. If you want an easy fix without any additional switches, check the "IGN" terminal in your fuse box. It should have power in START and RUN off of your key switch. I've used those when converting customer's cars to HEI, to provide 12 v. to the distributor, thus eliminating the resistor circuit for the factory points ignition. Just plug in a female spade terminal with the proper gauge wire for your coil, run it to your coil, and your done.
 

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Discussion Starter #5
I hooked to BAT since I got no power at IGN. Now I do suspect the ignition switch! I assume IGN is powered thru this switch.
 

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After 15 years with no electrical issues, the other day after a long drive, the next day car cranked but would not start. Checked power to distributor, which happens to be the issue. Ran a new 12 gage wire from + to fuss box with a switch and fuse. It starts and runs fine. Question - before I replace the ignition switch, what else does this switch turn on with key in run mode? I assume the fan and gauges. The fan and gauges do come on when key is in run position which tells me ignition switch may be good. Turn signals and tack are the only other issues now not working. I left the original wire to + coil off so that may be the tac issue. Any suggestions?
Main power to ign goes through the horn relay.
It's right next to the brake booster in the engine bay.
I went through that recently, and decided to get the real diagram from classiccarwiring dot com.
Best 24 bucks I have spent on this car.
Mine is also a 68.
 

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The neutral safety switch has nothing to do with ignition; it's only to prevent cranking the car in gear. The ignition circuit is separate from any "accessory" issues. If you want an easy fix without any additional switches, check the "IGN" terminal in your fuse box. It should have power in START and RUN off of your key switch. I've used those when converting customer's cars to HEI, to provide 12 v. to the distributor, thus eliminating the resistor circuit for the factory points ignition. Just plug in a female spade terminal with the proper gauge wire for your coil, run it to your coil, and your done.

Hi Rocketman and others,

I am having some of the same type of issues for a 1970 GTO. It starts sometimes and seemingly other times doesn't - I am in CA so it could be 50 degrees and it starts or it could be 77 degrees and won't start - and vice-versa.

It appears to have the power or want to crank the starter. I get power on START and RUN almost all the time looking at the control panel and lights. But, it just won't turn over.

I have replaced the starter. So that is unlikely.

Tomorrow, I will dig deeper into the IGN terminal in the fuse box tomorrow. But, can you elaborate plugging in a female spade terminal with the proper gauge wire for your coil, run it to your coil and you're done. I am a less than mediocre car repairman especially with some terms. But, very willing to learn or try.

Is there a video or YouTube video you can direct me to to understand the process better?

What tools and/or equipment do I need to buy for diagnosing this issue? Additionally in the near future, I will need to do a fair amount of re-wiring inside as the radio and other electrical wires are not working correctly.

Thanks!
 

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Hi Rocketman and others,

I am having some of the same type of issues for a 1970 GTO. It starts sometimes and seemingly other times doesn't - I am in CA so it could be 50 degrees and it starts or it could be 77 degrees and won't start - and vice-versa.

It appears to have the power or want to crank the starter. I get power on START and RUN almost all the time looking at the control panel and lights. But, it just won't turn over.

I have replaced the starter. So that is unlikely.

Tomorrow, I will dig deeper into the IGN terminal in the fuse box tomorrow. But, can you elaborate plugging in a female spade terminal with the proper gauge wire for your coil, run it to your coil and you're done. I am a less than mediocre car repairman especially with some terms. But, very willing to learn or try.

Is there a video or YouTube video you can direct me to to understand the process better?

What tools and/or equipment do I need to buy for diagnosing this issue? Additionally in the near future, I will need to do a fair amount of re-wiring inside as the radio and other electrical wires are not working correctly.

Thanks!
This sounds like typical bad connection or weak battery stuff.
Store bought battery cables with the pressed on ends are garbage.
I had the terminals literally vibrate off my jet boat.
Ruined that day.
I got some 2ga arc welding cable, some copper lugs, a crimping tool(the ones you smack with a hammer), a torch and some solder slugs.
Made my own.
The difference is night vs day.
Also, the only batteries I will buy are Optima.
Yellow for the car.
Blue for the boat, which I no longer have.
The red ones are crap, and will not charge after being drained even once.
If you have extreme weather, you have to eliminate that problem first.

As far as tool for diagnosis:
DVOM.
If your battery will take 15v or more under a charge, it's toast.
You only need 13v to charge a 12v battery.
Any more than 15v, and it's telling you
it's done.
Volts are like water pressure.
Amps are the water.
15v means it does not want the amps.

Hope that makes sense.
 

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..........I get power on START and RUN almost all the time looking at the control panel and lights..........can you elaborate plugging in a female spade terminal with the proper gauge wire for your coil, run it to your coil and you're done........
When you turn the key to START, all of your warning lights come on to show that they are working. You said "almost all the time". That is an issue. It could be a problem with the ignition safety switch- loose, worn, out of adjustment. Also, you need to check your neutral safety switch for the same reasons.
As to running a wire from the fuse box IGN terminal, that is only if you are NOT running a stock points distributor. The points require a resistor in the circuit to keep the points from burning up prematurely. After market or later factory (HEI) distributors require full battery voltage to deliver sufficient spark. That's why I would tap into the IGN terminal on the fuse box; however, the IGN terminal has absolutely nothing to do with cranking the engine. It is strictly to supply battery voltage to the ignition system in the START and RUN positions.
 

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Discussion Starter #11
NOS ignition switch came in today for the tilt steering. question is what is best way to get to the switch to replace. Not much out there in the way DIY info.
 

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Depends how flexible you are.
Switch is easy to access on the steering column. Some ways are easier than others
I wrap my legs over the seatback and dive in under the dash. Some like to remove the drivers seat. Not to hard on the bones that way.
 

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This sounds like typical bad connection or weak battery stuff.
Store bought battery cables with the pressed on ends are garbage.
I had the terminals literally vibrate off my jet boat.
Ruined that day.
I got some 2ga arc welding cable, some copper lugs, a crimping tool(the ones you smack with a hammer), a torch and some solder slugs.
Made my own.
The difference is night vs day.
Also, the only batteries I will buy are Optima.
Yellow for the car.
Blue for the boat, which I no longer have.
The red ones are crap, and will not charge after being drained even once.
If you have extreme weather, you have to eliminate that problem first.

As far as tool for diagnosis:
DVOM.
If your battery will take 15v or more under a charge, it's toast.
You only need 13v to charge a 12v battery.
Any more than 15v, and it's telling you
it's done.
Volts are like water pressure.
Amps are the water.
15v means it does not want the amps.

Hope that makes sense.
Thanks for getting back to me. I need a DVOM for this and other projects. So I will get that and dig in a little deeper with my battery ends/clamps. I think I changed them out previously.
 

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This sounds like typical bad connection or weak battery stuff.
Store bought battery cables with the pressed on ends are garbage.
I had the terminals literally vibrate off my jet boat.
Ruined that day.
I got some 2ga arc welding cable, some copper lugs, a crimping tool(the ones you smack with a hammer), a torch and some solder slugs.
Made my own.
The difference is night vs day.
Also, the only batteries I will buy are Optima.
Yellow for the car.
Blue for the boat, which I no longer have.
The red ones are crap, and will not charge after being drained even once.
If you have extreme weather, you have to eliminate that problem first.

As far as tool for diagnosis:
DVOM.
If your battery will take 15v or more under a charge, it's toast.
You only need 13v to charge a 12v battery.
Any more than 15v, and it's telling you
it's done.
Volts are like water pressure.
Amps are the water.
15v means it does not want the amps.

Hope that makes sense.

I was able to test the battery today and it came out at 12.09 volts using a Klein 700 DVOM. That should be acceptable correct? I will check the bad connection issue tomorrow. If that is not the issue and ideas for next steps?

Thanks!
 

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Discussion Starter #15
Not looking forward getting on back under dash but will install new ignition switch tomorrow. Not much room on top of column to remove the 2 screws l have been studying the service manual. Is their a rod that connects to the switch? I don’t see it in manual. Before I remove and replace, trying to figure out how it works..... and is it ok to remove 2 bolts holding up column to drop it for better access?
 

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yes, a rod connects the key tumbler to the switch. After installation, snug, but don't tighten the switch retaining screws. It may need slight adjusting to insure all the positions work properly. And yes you can lower the column, but make sure its supported.
 

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Discussion Starter #17
Switch installed today and all issues resolved. Turn signals, hood tack and 12v at coil now! Leaving the work around wire just in case (not hot of course) Thanks all. Lowering the steering column made it a much easier install.
 
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