Engine won't stay running

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silvergrande

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My Car
1971 Mustang Hardtop
Need help! After installing my engine, either the key cylinder or ignition switch stopped working. I can start the car by turning the key to on/run and putting a scredriver on the fender mounted solenoid. At first I changed the points and condenser set because the car would only turn over and not run. I then replaced the points and condenser. The car ran for a week and then stopped running again. It seems like the points and condenser are getting too much voltage?? AND BURNING OUT THE CONDENSER??


[/u]Need help! After installing my engine, either the key cylinder or ignition switch stopped working, (the key cylinder will not turn to the acc position either),I can start the car by turning the key to on/run and putting a scredriver on the fender mounted solenoid. At first I changed the points and condenser set because the car would only turn over and not run. I then replaced the points and condenser. The car ran for a week and then stopped running again. It seems like the points and condenser are getting too much voltage?? AND BURNING OUT THE CONDENSER??. The engine runs, BUT AS SOON AS i PUT IT IN drive it stalls out. I did have a stereo installed in the car. Maybe the installer used the wrong wires to give the radio a constant 12 volts?? I think maybe the coil is getting 12 volts constantly when it should only get about 9 volts after the intial engine start of 12 volts. Well can anybody help me troubleshoot? I don't want to start replacing parts that don't need to be changed! Thanks everybody.

 
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get a volt meter, turn the key to run and ck the voltage to the + or bat side of coil,should be around 8-9 volts. next get someone to turn the key to start and see if there is 12 volts on the small wire closest to bat terminal on the solenoid. if not, try jumping the wires at the neutral safety switch and see if it starts then. let us know when you try those 2 things.

 
get a volt meter, turn the key to run and ck the voltage to the + or bat side of coil,should be around 8-9 volts. next get someone to turn the key to start and see if there is 12 volts on the small wire closest to bat terminal on the solenoid. if not, try jumping the wires at the neutral safety switch and see if it starts then. let us know when you try those 2 things.
Click to expand...
Okay, I'll try that tommorow, monday, thanks

 
get a volt meter, turn the key to run and ck the voltage to the + or bat side of coil,should be around 8-9 volts. next get someone to turn the key to start and see if there is 12 volts on the small wire closest to bat terminal on the solenoid. if not, try jumping the wires at the neutral safety switch and see if it starts then. let us know when you try those 2 things.
Click to expand...
Okay, I'll try that tommorow, monday, thanks
Click to expand...
Hi I'm back finally sorry for the delay.

Okay, coil check reads 12 volts instead of 9 at run position.

Turned key to start. Tested voltage at post labeled "S" on solenoid no voltage at all. Tested voltage on post "I", constant 12 volts.

Did not try jumper wire on neutral safety switch yet. So what do you think is wrong? Please help!

 
OK, you've narrowed the problem down to 3 possibilities, the ignition switch, the neutral safety switch, or wiring/connectors. You can rule out the ignition switch by checking for voltage on the starter terminal when you turn the switch to start. You can check the neutral safety switch by disconnecting the connector and checking for continuity across the terminals (on the switch side) when the transmission is in park or neutral.

When you check the voltage at the + terminal on the coil you need to make sure the points are closed, so the resistor wire is "loaded". If you were using a digital voltmeter it won't load the resistor enough to make much difference on the voltage. With the points closed, or the - terminal on the coil grounded, you should get a reading of 6 or 7 volts, if you have a resistor or resistor wire in the circuit.

 
OK, you've narrowed the problem down to 3 possibilities, the ignition switch, the neutral safety switch, or wiring/connectors. You can rule out the ignition switch by checking for voltage on the starter terminal when you turn the switch to start. You can check the neutral safety switch by disconnecting the connector and checking for continuity across the terminals (on the switch side) when the transmission is in park or neutral.

When you check the voltage at the + terminal on the coil you need to make sure the points are closed, so the resistor wire is "loaded". If you were using a digital voltmeter it won't load the resistor enough to make much difference on the voltage. With the points closed, or the - terminal on the coil grounded, you should get a reading of 6 or 7 volts, if you have a resistor or resistor wire in the circuit.
Click to expand...
How do you ground the terminal on the coil, or make sure the points are closed? On the continuity check for the neutral safety switch can I get to the terminals on the auto floor shift from inside the car or from the bottom of the car?

 
Hmm thanks for sharing this wonderful post, I really like to your thread.It is quite helpful discussion according to me, thank you so much for the impressive post......

 
You just run a jumper from the - (minus) terminal of the coil to ground, a jumper with alligator clips works best. Don't leave it like this for very long, as this energizes the primary side of the coil and it will heat up, along with the wire that supplies it.

The neutral safety switch is mounted on the transmission, where the gearshift lever is connected. This is also where you would adjust the switch, if needed.

 
You just run a jumper from the - (minus) terminal of the coil to ground, a jumper with alligator clips works best. Don't leave it like this for very long, as this energizes the primary side of the coil and it will heat up, along with the wire that supplies it.

The neutral safety switch is mounted on the transmission, where the gearshift lever is connected. This is also where you would adjust the switch, if needed.
Click to expand...
So, can you get to the neutral safety switch from inside the car?

 
No, you can only get to it from underneath, unless the connector can be reached from under the hood. I can see the connector on mine, but can't do much with it, unless I take off the brace, even then not sure I would be able to pull it apart.

The wires you are interested in are the red with light blue stripe. The black/red and black/pink wires are for the back-up lights, which also are activated by the neutral switch.

 
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There is a 4 pin connector and a 1 pin connector taped together that run from the firewall down to the NSS and the light for the shifter. If you want to remove the NSS you have to remove the kick down tubular linkage at the NSS (secured by an E clip). Then remove the kick down lever. YOU MUST HOLD THE LEVER STATIONARY TO PREVENT OVER ROTATION OF THE SWITCH WHEN YOU LOOSEN THE NUT SECURING IT OR THE SWITCH MAY BE DAMAGED. The switch is bolted to the transmission with 2 small hex headed bolts. The NSS is not meant to be serviced but can sometimes be disassembled and repaired. I'm not sure I understand the symptoms clearly. Will the starter engage in neutral (or just slightly either side of the shifter Neutral position) using the key? Or is the symptom the starter will engage but the engine won't stay running when the starter dis-engages. Sorry if I'm just not reading the posts properly. Just trying to help. Chuck

 
UPDATE ON NO RUN ISSUES. I REPLACED THE KEY CYLINDER FIRST. THE ENGINE STARTED RIGHT UP AND CONTINUED TO RUN. i HAVE ALSO REPLACED THE IGNITION SWITCH. -------------------------------------------------->>>>>>>>

I want to check the resistance wiring for 9 volts. I'm worried about damaging the coil. When I do the test do I remove the wiring plug from both the batt side of the coil and the dist side of the coil. Or do I leave the dist wiring plug installed and only remove the Batt side wiring plug. Like I said I want to do the resistance wire test but not damage the wiring in the process. I just need some clarification on what to leave connected and disconnected. Also the pos and neg terminals/cables should be kept connected to the battery right? Any help with this test would be greatly appreciated.

 
Just remove the yellow connector, C-17 from the Batt terminal of the coil. The wire number is 16 and it is Red with a Light Green stripe. battery is connected, key to the run position. Voltmeter set to VDC, range 10V or greater, black lead to ground, red lead to the yellow connector removed. You can't hurt anything. Chuck

 
When measuring voltage across a resistor the voltage (voltage loss) depends entirely on the load on the circuit. If you measure the voltage at the coil wire connector with it disconnected you will read close to battery voltage, depending on the type of voltmeter used. The way Ford says to test the circuit is attached.

Ignition testing.pdf

 

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  • Ignition testing.pdf
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When measuring voltage across a resistor the voltage (voltage loss) depends entirely on the load on the circuit. If you measure the voltage at the coil wire connector with it disconnected you will read close to battery voltage, depending on the type of voltmeter used. The way Ford says to test the circuit is attached.
Click to expand...
It is true, with a high input impedance voltmeter, he will read near voltage applied with it disconnected. Unless someone has replaced the high resistance wire with a regular wire, and he can't tell, that likely means the wire is good, not open. The Ford check, if I read figure 5 correctly, has you reading across the full length of the resistance wire with current flowing, which is a more precise check. I wanted to give him a quick go/no-go check. The resistance of the wire is 1.3 to 1.4 ohms. The resistance across the primary winding of the coil is also about 1.4 ohms. If the battery is fully charged at 13.2 VDC, and the total series circuit resistance is 2.8 ohms: 13.2VDC/2.8 ohms=4.71 Amps flowing through the two series resistances. 4.71 Amps X 1.4 ohms=6.594VDC across the resistance wire. That is where the Ford specified 6.6 VDC comes from. The voltage across a fixed resistor is a function of the current flowing through the resistor and it's resistance (E=IR). It was not my intent to mis-inform anyone. I apologize if I did. Chuck

 
Wow, it has been so long since I actually applied Ohm's Law....LOL! Good to see it still works the same!

 
OK, you've narrowed the problem down to 3 possibilities, the ignition switch, the neutral safety switch, or wiring/connectors. You can rule out the ignition switch by checking for voltage on the starter terminal when you turn the switch to start. You can check the neutral safety switch by disconnecting the connector and checking for continuity across the terminals (on the switch side) when the transmission is in park or neutral.

When you check the voltage at the + terminal on the coil you need to make sure the points are closed, so the resistor wire is "loaded". If you were using a digital voltmeter it won't load the resistor enough to make much difference on the voltage. With the points closed, or the - terminal on the coil grounded, you should get a reading of 6 or 7 volts, if you have a resistor or resistor wire in the circuit.
Click to expand...
How do you ground the terminal on the coil, or make sure the points are closed? On the continuity check for the neutral safety switch can I get to the terminals on the auto floor shift from inside the car or from the bottom of the car?
Click to expand...


Need help! After installing my engine, either the key cylinder or ignition switch stopped working. I can start the car by turning the key to on/run and putting a scredriver on the fender mounted solenoid. At first I changed the points and condenser set because the car would only turn over and not run. I then replaced the points and condenser. The car ran for a week and then stopped running again. It seems like the points and condenser are getting too much voltage?? AND BURNING OUT THE CONDENSER??


[/u]Need help! After installing my engine, either the key cylinder or ignition switch stopped working, (the key cylinder will not turn to the acc position either),I can start the car by turning the key to on/run and putting a scredriver on the fender mounted solenoid. At first I changed the points and condenser set because the car would only turn over and not run. I then replaced the points and condenser. The car ran for a week and then stopped running again. It seems like the points and condenser are getting too much voltage?? AND BURNING OUT THE CONDENSER??. The engine runs, BUT AS SOON AS i PUT IT IN drive it stalls out. I did have a stereo installed in the car. Maybe the installer used the wrong wires to give the radio a constant 12 volts?? I think maybe the coil is getting 12 volts constantly when it should only get about 9 volts after the intial engine start of 12 volts. Well can anybody help me troubleshoot? I don't want to start replacing parts that don't need to be changed! Thanks everybody.
Click to expand...
 
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