Car was running fine, started itermittely not starting, then would start. Now, I'm getting nothing when turning the key to START.

All tests with Ignition ON. I get 12.18 volts at the following locations: battery, electrical junction at radiator support, horn relay, purple wire on column before ignition switch. The test light will light at all fuses on the fuse box (inside car), the backup light switch (red wire) and at positive coil terminal.

I have 0 volts at neutral safety switch purple wire or at the S terminal at the starter.

It's a '71 Chevelle, that originally had a 307 and TH-350 with column shift. I have a 350/TH-350 and converted to aftermarket floor shifter. I've bypassed the original NSS, since it is now down at the floor shifter.

Any ideas? All I can think of is the Ignition switch is bad. I changed it in Dec-05 an AC Delco replacement. Maybe it's bad again?

Thanks!

I have 0 volts at neutral safety switch purple wire or at the S terminal at the starter.


You need to hold the key in the crank position when testing for power in those places. Do that and post back.

You could also have a bad, or misadjusted neutral safety switch.

You need to hold the key in the crank position when testing for power in those places. Do that and post back.

You could also have a bad, or misadjusted neutral safety switch.

I have 9.90 volts at the neutral safety switch down on the aftermarket floor shifter. Won't be able to read the volts at S terminal on starter until fiance gets home (hard to hold the key to start position and be under the hood at some time :) )

Thank you.

with the key in START position, I'm getting 8.58 volts at the S terminal. The battery is showing 12.18 volts in a non-starting state.

I'm getting no click of the starter solenoid or anything. Turn the key to start and silence. I'm stumped :confused:

That voltage is much to low with the starter not spinning....

First try jumping the starter. Using the screwdriver trick (do not let it touch ground!!) or added a 2nd wire (use a 10g) to the "S" terminal and running it close to the battery with a 30 amp inline fuse, apply battery power to the "S" terminal (warning, this bypasses all safety devices, be sure trans is in park). Will the starter crank then? If it won't crank, the problem is with the starter/solenoid. If it will crank, then its a wiring problem. With you meter, start tracing the wire from the aftermarket floor shift back to the dash, and test the voltage (Be sure to hold key in crank position) If the car was originally a column shift, the wire could go back to the original NSS. (it is on top of the column near the firewall) Check to see if the switch is still there or bypassed, and if bypassed, the connection (if poor, solder the connection)

Just added info, from the IGN switch to the original NSS the wire color is 12g purple w/ white stripe. From the original NSS to the starter "S" terminal is 12g purple.

Is there a splice in the original neutral safety switch wires?

That voltage is much to low with the starter not spinning....

First try jumping the starter. Using the screwdriver trick (do not let it touch ground!!) or added a 2nd wire (use a 10g) to the "S" terminal and running it close to the battery with a 30 amp inline fuse, apply battery power to the "S" terminal (warning, this bypasses all safety devices, be sure trans is in park). Will the starter crank then? If it won't crank, the problem is with the starter/solenoid. If it will crank, then its a wiring problem. With you meter, start tracing the wire from the aftermarket floor shift back to the dash, and test the voltage (Be sure to hold key in crank position) If the car was originally a column shift, the wire could go back to the original NSS. (it is on top of the column near the firewall) Check to see if the switch is still there or bypassed, and if bypassed, the connection (if poor, solder the connection)

Just added info, from the IGN switch to the original NSS the wire color is 12g purple w/ white stripe. From the original NSS to the starter "S" terminal is 12g purple.

I'll have to try the S terminal jumper on Saturday. I have to fly to Dallas today.

Is there a splice in the original neutral safety switch wires?

To answer both of the questions on the NSS. First, I've done all modifications on the car (it was bone stock when I bought it). So, I have the answers! I simply unplugged the factory NSS harness and Backup light harness from the NSS on the column. I used 18ga. wire to extend the wires down to the floor shifter NSS and backup light switches. A spade type to connector was used to transfer power from the original NSS and backup light harnesses (I know this is a terrible way to do the "splice"). Since installing the floor shifter in 2000, I've always had problems starting the car (so I figured out I could use a paperclip to loop the wires on the original NSS harness). Well, now, that doesn't start the car anymore.

I went and took some more voltage readings (that's all I have time for until I get back from Dallas). All tests done with key in START position.

Purple/white wire at factory NSS Harness: 11.75 volts
Purple/white wire at floor shift NSS switch: 10.00 volts

With factory NSS harness plugged into the NSS switch on the column (this NSS was replaced in 1999 or so):

Purple/white wire: 11.24 volts
Purple wire: 10.89 volts.

With the factory NSS harness plugged into the NSS switch on the column I could hear the start solenoid make a faint click (not a click as in the starter being engaged to the flexplate).

That's about all I can do until this weekend. Wish I could do more diagnosing, but work calls.

Thanks for the tips and helping me firgure out the problem.

To answer both of the questions on the NSS. First, I've done all modifications on the car (it was bone stock when I bought it). So, I have the answers! I simply unplugged the factory NSS harness and Backup light harness from the NSS on the column. I used 18ga. wire to extend the wires down to the floor shifter NSS and backup light switches. A spade type to connector was used to transfer power from the original NSS and backup light harnesses (I know this is a terrible way to do the "splice"). Since installing the floor shifter in 2000, I've always had problems starting the car (so I figured out I could use a paperclip to loop the wires on the original NSS harness). Well, now, that doesn't start the car anymore.

First, 18g wires are much to small to use for the starter circuit. (18g would be ok for the back up lights) No wonder you always had problems starting. I would use at least a 12g, but 10g would be better as you are adding wire length the circuit. Crimp and solder all connections. The starter solenoid draws more power than anything else in the car (except the starter itself) You may need to replace the solenoid and NSS as continued use under low voltage could have burnt the contacts in in them.

First, 18g wires are much to small to use for the starter circuit. (18g would be ok for the back up lights) No wonder you always had problems starting. I would use at least a 12g, but 10g would be better as you are adding wire length the circuit. Crimp and solder all connections. The starter solenoid draws more power than anything else in the car (except the starter itself) You may need to replace the solenoid and NSS as continued use under low voltage could have burnt the contacts in in them.

Yeah, my wiring choices in the past were not so good :o. I've since learned to solder and that's how I spice wires these days. I need to go back and redo a lot of wiring. One thing is, I've taken out a lot of original equipment (A/C compressor, alternator, etc.) and have wiring harness taped up that need to be permanently removed. Can I just remove these wires from the bulkhead at the engine side?

I'll order up some quality wire to fix this NSS butcher job and track down new a new NSS switch at the floor shifter. I have another starter laying around in case the solenoid is bad on the starter currently installed in the car. I think I'll get my wiring hack jobs from the past fixed once I get this current problem solved.

Thanks again for sticking with me on this problem :thumbsup: . I'll post back when I have an update this weekend.

Well, I finally got the car started. I fabbed up the jumper 10g wire with a 30 amp fuse (inline) to connect the S terminal on starter to the battery. The starter solenoid would click, but the starter motor would not turn over. I even charged the battery to top it off. Still, the starter would not turn. So, I replaced the starter with an extra one I had laying around that I knew worked. Plugged the factory NSS harness back into the stock NSS on the column (as I have not yet acquired enough 10g wire for extending down to the floor shifter). The engine turned over and fired up!

So, now I can go fix all my crappy wiring :yes:

Thanks for helping me out Greg. Way cool :thumbsup:

Alan