Volt relay??? - Pontiac GTO Forum
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post #1 of 11 (permalink) Old 06-14-2017, 06:01 PM Thread Starter
 
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Volt relay???

So having problems with my 67 gto not starting every now and then
.no crank nothing...been through all the usual suspects, starts, sylinoid, battery, battery cables, ignition switch, neutral safety switch, wiring harness......anyway my mechanic fixed thus same problem about 6 years ago. When I just talked to him he said back then it was some voltage relay under the dash that was bad...but for the life of me I can not find any info or diagram or part in catalog that matches his description....is there such a thing under the dash of a 67 gto???....if yes please tell me the proper name and send a pic to help me....thanks...its driving me nuts
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post #2 of 11 (permalink) Old 06-14-2017, 06:50 PM
 
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Originally Posted by BYTOR84 View Post
So having problems with my 67 gto not starting every now and then
.no crank nothing...been through all the usual suspects, starts, sylinoid, battery, battery cables, ignition switch, neutral safety switch, wiring harness......anyway my mechanic fixed thus same problem about 6 years ago. When I just talked to him he said back then it was some voltage relay under the dash that was bad...but for the life of me I can not find any info or diagram or part in catalog that matches his description....is there such a thing under the dash of a 67 gto???....if yes please tell me the proper name and send a pic to help me....thanks...its driving me nuts
Don't know of any relay that you are talking about. Here are some wiring diagrams and maybe you can identify it, but I don't see one. 67 GTO Wiring Diagram
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post #3 of 11 (permalink) Old 06-15-2017, 07:11 AM
 
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I'm jumping here with a longshot. In the '70's I drove a tow truck on nights and weekends for extra cash. I jump started more cars than I care to remember. I wasn't a mechanic and I'm still not, but there was a no start trick I was taught for GM products. So here goes. You mention you replaced the starter and the solenoid. Rebuilds? If you turn on the headlights and then try to start the car, do the lights dim? If not, then the solenoid might be bad. Here's the trick. Car in neutral or park. E brake on. Have someone in the car with their foot on the brake ready to start the car. Get a hammer and wiggle under the car. Tell the driver to hold the key over in the start position. Now whack the starter with the hammer. This would work about 75% of the time when I tried it. I would tell the driver that when they got home to park the car where someone could do the same trick in the morning, because the car was likely not to start again. On another note, I had a bad voltage regulator brand new out of the box. Never suspected that's why the lights on my '67 flickered. Took a year before it occurred to me that it might be bad. Good luck.

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post #4 of 11 (permalink) Old 06-15-2017, 08:23 AM
 
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no start

.no crank nothing... you say in your post
.................................................. .................


you dont tell us ..............

do your lights come on or the heater fan blow at this time of no crank nothing works ?

is the battery dead and need a jump/or charge ?

the voltage regulator is on the firewall under the hood to the left of the master cylinder ..... 2.5 " square 4 wired plug...

what brand is your regulator ...? usually stamped on the cover....

I am not a 67 guy ,,, but I am a 68 and there is no 'relay ' under our original dashes I have seen ....



Scott

Last edited by BLK69JUDGE; 06-16-2017 at 07:52 PM.
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post #5 of 11 (permalink) Old 06-16-2017, 07:00 AM
 
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Yeah, no relay. Sounds like a bad starter / solenoid, or a simple loose wire. I say simple because it is going to take you 3 years to find it, and when you do you will be pissed because it was so obvious!
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post #6 of 11 (permalink) Old 06-18-2017, 10:16 PM Thread Starter
 
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thanks for the suggestions. But like i said I have been through all the usual suspects. starter, solenoid, wires,ignitions , neutral safety switch, cleaned all the grounds.

When it happens I have headlights and such. it just wont turn over. I replaced the voltage regulator in the past..on the fire wall ..but to my limited car knowledge that has more to do with the alternator than starting..if im not mistaken.

So the wires from the ignition switch dont go through any volt relay or anything? its tough to trace and Im so darn big at 6ft 7 in its tough to get under the dash
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post #7 of 11 (permalink) Old 06-18-2017, 11:28 PM
 
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Originally Posted by BYTOR84 View Post
thanks for the suggestions. But like i said I have been through all the usual suspects. starter, solenoid, wires,ignitions , neutral safety switch, cleaned all the grounds.

When it happens I have headlights and such. it just wont turn over. I replaced the voltage regulator in the past..on the fire wall ..but to my limited car knowledge that has more to do with the alternator than starting..if im not mistaken.

So the wires from the ignition switch dont go through any volt relay or anything? its tough to trace and Im so darn big at 6ft 7 in its tough to get under the dash
The starter wiring diagram 6E-1 that was linked in earlier reply doesn't show any relay under the dash. Looks like the ignition switch has constant 12v power from the starter and then a "signal wire" from the ignition switch to the small terminal on the starter solenoid. When you turn the key to the Start position, the ignition switch provides power to an electromagnet inside the starter solenoid and it pulls a metal cylinder in against a spring until it makes contact with two large electrical posts (one connected to the battery cable and the other to the starter motor). That metal cylinder also has a lever that fits over a collar and moves the starter gear towards the flywheel/flex plate ring gear which causes the engine to turn. When the key is released and returns to the Run position, the 12v power to the small terminal of the solenoid is interrupted...the electromagnet loses power...the metal cylinder returns to its home position which simultaneously kills power to the starter motor and pulls the starter gear away from the ring gear.

Since the mid 50s, vehicles with automatic transmissions usually have some sort of neutral safety switch. They are usually fairly simple and require the shifter to be in park or neutral or it won't allow the ignition switch "signal" to reach the small terminal on the starter solenoid. This is the first place I would check based on the symptoms you describe. With the drive wheels off the ground, hold the ignition switch in the Start position and move the shift lever through the various positions and see if the engine cranks. If the engine cranks in any position besides Park or Neutral then you have an adjustment issue with the gear selector.

I am not familiar with automatic transmission GTOs so my suggestions are based on the wiring diagram linked earlier and general knowledge of other General Motors vehicles from the same era. I hope this helps.

Good luck.
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post #8 of 11 (permalink) Old 06-19-2017, 09:14 AM
 
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Originally Posted by BYTOR84 View Post
thanks for the suggestions. But like i said I have been through all the usual suspects. starter, solenoid, wires,ignitions , neutral safety switch, cleaned all the grounds.

When it happens I have headlights and such. it just wont turn over. I replaced the voltage regulator in the past..on the fire wall ..but to my limited car knowledge that has more to do with the alternator than starting..if im not mistaken.

So the wires from the ignition switch dont go through any volt relay or anything? its tough to trace and Im so darn big at 6ft 7 in its tough to get under the dash
You are correct about the voltage regulator. Its on the firewall and is for the charging system.

You have a 50 year old car. My guess is you have a loose wire somewhere, a bad ground, a frayed wire, a loose starter bolt (I've seem this cause all sorts of electrical gremlins), or something similar. It is possible your starter is going bad as well.

Good luck!
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post #9 of 11 (permalink) Old 06-19-2017, 07:28 PM
 
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Did you review the color coded wiring diagram I gave you the link to? You will need this to trace/test wires and apply the words of wisdom we are providing. You will also need to buy a few electrical testing tools to do this yourself, otherwise you will need to bring the car to a shop. You need a 12V light tester and a 12V continuity tester or Ohm meter. To use the continuity or Ohm meter, you want the battery cable off as you do not want 12V going through the wiring.

Well, you could test the starter as well. If you can make a long wire with a small alligator clip on the end and clip the end on the "S" terminal (are you sure you have the purple wire on the "S" terminal of the solenoid and NOT the "R" terminal. If connected to the "R" terminal you will get nothing when you turn the key) and then touch the other end to the battery Positive + terminal, it should energize the solenoid and spin over the starter. If like me, you got the big hands, you may want to drop the starter and either do the same thing on the ground or take it to a shop/auto parts store and let them test it.

You have to eliminate 1 item at a time to narrow down the problem. Begin with the starter/solenoid and then work back from there. With the starter still dropped and the battery disconnected, get a continuity tester - Lowe's has a great one for $29 that has a wireless remote you can remove. Attach one end of the tester to the key/ignition side/wire and attach one end to the purple wire at the starter. (Look at the color wiring diagram, the dark purple wire coming off the solenoid is what you want to test) If the wire is good, the remote unit will go off and make a sound, so you know it is not the purple wire or your neutral safety switch. If it does not, then you have a purple wire issue or neutral safety switch gone bad. It could be the wire itself, the neutral safety switch, or the bulkhead plug where the engine wiring harness connects to the interior/dash harness. You could have corrosion issues or the wire could even be broken somewhere along its path. You can pull the bulkhead plug and use the continuity tester at the starter end to the end at the bulkhead plug. If it works, you are good.

If not, then your wire could be bad/broken inside the casing, or corrosion at the bulkhead. Replace the wire or clean the corrosion. If it works, then do a continuity test from the bulkhead plug where the wire then goes to the neutral safety switch. You will have to locate this, which I suppose is on the automatic shifter and under the console (if manual trans then you don't have this switch). Test it using the continuity tester where the purple wire goes into the switch and then test the switch where the purple wire goes out. Test in both "Park" & "Neutral" shift positions as the switch should work in both positions. Then test continuity from the output side of the switch to the ignition wire at the ignition switch plug. If your continuity tester goes off, it is good, if not, you may have a bad wire - replace or repair and then re-test it to make sure it works.

Install your starter/solenoid and hook up all your wires/battery cable - purple wire to the "S" terminal of the solenoid. With the ignition key plug still removed, find the power wire on that plug that goes onto the ignition switch and test it for 12V with your light tester. You have to have 12V going to the switch which will in turn send power through the switch when you turn the key "On" AND to the "Start" position. If you have power at the plug, you are good. If not, trace the wire like the purple wire and find out where the power begins and stops and fix accordingly.

If you do have 12V, then next check your ignition/key switch. Find the prong on the ignition switch that corresponds with the 12V battery wire coming off the plug. Typically, the back of your switch will have this labelled as "BAT". Attach one end of the continuity tester to this prong. Then attach the other end to the prong that says "SOL" (Solenoid). Turn your key to the "Start" position just like you would be starting your car. The continuity tester should go off IF the key switch is working. If it is not working, then try a few of the other prongs just to make sure the "Start" function is not one of these instead. If your switch is bad it needs to be replaced.

If your starter/solenoid test good, your purple wire is on the "S" terminal of the solenoid, the purple wire is good, the neutral safety switch is good, 12V supply wire to the ignition switch is good, and your ignition switch are all good, then I am lost at this point.
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post #10 of 11 (permalink) Old 06-20-2017, 02:18 AM Thread Starter
 
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Wow!!..that is a lot to digest...thanks for all the info...now I have to wait until it happens again to go through all of that.
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