tstruth

Hello all,
I seem to be having more difficulties with my 75. It has been a enjoyable project so far. But just when I think she is close to driving something else happens. She will not start. I have new battery with new connectors. Checked for ground on the frame she is good and clean. Installed a new distributor. Had trouble with the alarm wires when I installed it. Removed them and she fired up. Timed her and I thought I was good. I installed an aluminum radiator with electric fans and powered it up to the back of the alternator and everything seem to be fine. Put some new sneakers on her and I was ready to drive it around the block and see how my new front end rebuild felt. Had the car running and when I shut it down in the driveway she would not start back up. I jumped her and put her back in the garage. Charged the battery which didn't seem to low and now she will not even make a click. I bought a new battery, new connectors and still nothing. I thought it might be the ignition switch. I did have allot of play in the lock cylinder. I pulled the column and found that the spring holding the ignition lock tension was not put in right. Checked the ignition switch and it seemed good like it was new. I made sure she moved up and down and nothing was stuck. I installed it back on the column in on the off position and my lock cylinder felt better and activated the switch perfectly. Installed the column back in and still nothing. I am about to order a new ignition switch, but I do not feel that is the problem. I have 12.6 volts to the starter, distributor, alternator. Not sure if its a kill switch, safety switch. I did put her in neutral and try to start her no luck.

Any help would be greatly appreciated.

henrikse

I wouldn't buy parts unless you know they are required. You can get a remote starter switch and install it on the starter battery lead and solenoid and see if it cranks. Odd when you say you had to boost in driveway and started but something changed as boosting in garage does not work. Even though you have 12.6 at starter the cable from battery to starter could be corroded or bad. They get corrosion inside. Soon as there is a load the voltage could disappear. Use a jumper cable and go from battery to large post at starter and give a try. It could also be the solenoid . If you need a copy of your wiring diagram let me know?

Good Luck
Gary

Peterbuilt

Is your '75 auto or stick?

With the shifter in neutral or park, the parking brake on and the wheels chocked momentarily run a jumper from the 'main large battery cable' to the " 'S' start wire" and see if the starter turns on.



'75 schematic:
https://docs.google.com/viewer?a=v&p...WRiNTdjNjdkNTQ

tstruth

Tried connecting the jumper cable to the starter and she sparked pretty good. How could it be bad if Im getting the spark? Its an automatic. the solenoid is new with the distributor. I ran the jumper and yes the starter kicked on. Thanks guys. Not sure what that means but it's nice to know she is alive.

Peterbuilt

With the key in START, it sends 12 volts to the PURPLE wire that connects to the 'S' terminal and that turns on the starter.
Jumpering from the BATTERY terminal to the 'S' terminal tests to see if the starter works.

Do you have this relay under your hood and on the firewall?

tstruth

Yes. It looks a little different. It has two connectors one singe and one three prong purple, blue, and orange.

tstruth

Peterbuilt

All '74 Corvettes and some early '75's had a "Starter Interlock Override Switch" I just wanted to see if you had one or not and it looks like yours was bypassed and removed from the firewall (see the two holes where it was).

The two parts in your picture are the heater relay and the resistor.
They have nothing to do with your problem.




#1 You want to be sure that the starter works.
#2 You want to confirm 12 volts to the purple wire at the starter with the key in START.

Here's the basic circuit:




Have you tried moving the shifter betewwn P and N with the key in start?

tstruth

I do see the two holes. The Starter kicked on when I ran jumper from battery to the S terminal. I checked the power and there is 12V at the S terminal with the key on. I attached a picture. It has a blue insulated strip. I have tried shifting it to N and P and trying it. No luck with that. If I got the starter to turn on with the jump wire does that mean that there is a short somewhere in the line or a faulty ignition switch?

Thanks for helping me out with this.

Peterbuilt

This should help.

Peterbuilt

You said ' a short somewhere or a bad ignition switch'.
It could be a bad or misadjusted key switch.
An out of adjustment on the switch at the bottom of the column
A bad NSS switch
Or something else like a poor ground.
That's what we're trying to figure out

derekderek

An open. Not a short. Opens are a gap electricity cant cross. Broken wire, bad switch, something. Shorts act like an arc welder.

henrikse

When you say it sparked pretty good that tells me there is a load or short on it? If the battery cable is connected and you have 12 volts then adding a second wire should not cause spark? Did it try to engage? Did you have the key on? I would check from the battery to the starter and follow this wire and look for damage. Or use an ohmeter and disconnect from battery and starter and make sure it is not reading?

tstruth

Thanks Henrikse,
I will try that when I get home from work. Peterbuilt has me thinking it might be my ignition switch. When I got the spark it was me hitting the cable against metal and the power wire on the starter. When I took a jumper from the battery to the S terminal the starter engaged.
Not sure if you need a special ignition switch for Tilt and Telescopic.The one I ordered is made for it. Not sure about the one that is on it now. I ordered a new ignition lock as well seeing that this one pulls out when the key is on start.
When I put the new one on the Jim Shea paper says I should have the ignition switch in the off Position, Hold and rotate the lock cylinder clockwise. Insert and slowly with pressure turn counter Clockwise until it locks in to place. The shift lock on the column has the cable cut from the PO. So does this mean I should have it in the up position or does it matter?

tstruth

Disconnected the positive wire to the starter and jumped the positive battery terminal to the starter post. Same outcome. I dropped the column and checked ignition switch. Power to the white terminal read 12V to the center connection and ground to the other. The two other connections had no reading. The Black terminal read 12V and .05. There is no power to the S terminal when the key is on. Waiting on new switch. It had allot of slop on it when the tumbler was loose inside the column. I repositioned the spring to apply more pressure to it. I had to push the key in hard to get the lock cylinder to engage.

I'm still enjoying the challenge. Learning much from this.
Thanks again for all the input.

Peterbuilt

The lever on the firewall side on the column should be secured in the UP position.

tstruth

Hello all,

Still stumped. I have replaced the ignition switch and lock cylinder. That was my bad. I thought that was the problem. I pulled the starter and checked the solenoid. It reacted fine. Motor worked. Bendix popped out like it should. I checked all the fuses again any they are fine. the small fuse on the bottom of the panel reads ground. Not sure if that is correct and I do have a brown wire that is connected beside it. Does that feed to the distributor? not sure why this has no power.

Any suggestions are greatly appreciated

tstruth

It was the NSS. The PO bypassed the switch with a fusible link. The 20 amp fuse was blown. Happens when you shift to N.
Not sure why?
Well I will do some more research and wire tracing.

Thanks again to Peterbuilt, Henrikse.