jdubdeck

Hello Everyone,

It seems as though I may be having some issues starting my 1975 Corvette and I have tried just about everything without any luck. After about a 1.5 hour drive moving the car from NJ to PA she decided that she didn't want to start again. All I got was a click. So I checked the cables which tested good. The battery tested good. The safety switch tested good.

Running out of options I went ahead and replaced the starter which now it does not make any click at all. What I am really confused about is that I am measuring 8V between the red solenoid cable and the positive cable on the starter without the solenoid cable being connected and the ignition in the "off" position.. Does this mean there is a short somewhere? If anyone has any more ideas of things to try I would appreciate the help! If it helps at all I do have power to the rest of the car.

Peterbuilt

Is the ground from the battery to the frame good?
It's on the frame under the drivers seat.

jdubdeck

Yup it's good that was one of the first things I checked. I also cleaned the connection points on the frame and battery. I was toying around with it last night and the starter wires are getting power I just can't tell if there is a short somewhere keeping the starter from turning. Do you think there could be a problem with the ignition switch?

SH-60B

I agree with checking the ground, but that 8V should be over 12V. That red cable is the battery positive and should read the same as the battery. I think you have a discharged battery. Check it with your meter.

KenSny

I had a similar problem a couple of years ago, drove me nuts.

First a question. Does your battery have both top and side terminals?

If yes, then maybe this will help you find the problem.

When I measured voltage it all seemed good. I charged it using the top terminals. I finally took the battery out and to a battery store to replace it. They tested it and showed me that I had a bad, inside the battery, side terminal that would intermittently lose contact. Top terminals were good. I replaced it.

stumpshot

Is it an automatic? If so, try starting in neutral or jiggle the shifter in park and also in neutral. If a standard, check the safety switch at the clutch.
Good luck
Stumpshot

jdubdeck

I just checked and the battery and it only has top posts on it and I took the battery to get it checked and it checked out fine. I think I have limited the problem down to one of the fusible wires is blown going to the starter or the voltage regulator capacitor is shot. I checked the voltage again but with the wires connected to the starter and found that the full voltage isn't getting to the starter to activate the solenoid. When I jump the starter straight to the battery it turns so atleast the starter and solo kid is good

GUSTO14

I would check the integrity of your ignition switch... the one on the top of the steering column (just above your foot).



There is a rod that travels down the top of the column (from the key switch) to the above switch. As you turn the key the rod moves a slide inside the switch that directs power to the different contacts that correspond to the keys' position. There are hex headed sheet metal screws that hold it tight to the column jacket once it is positioned correctly. Over time the screws can come loose and allow the switch to move at which point the key position may no longer correspond to the correct contacts inside the switch.

The switch itself is also sandwiched around the center slide and held together by metal tabs that hold the "sandwich" tight. The tabs themselves over time can loosen and not compress the switch tight enough and also affect the internal contacts. I have found them loose at times and even disassembled them to clean the contacts much as you would a set of points.

While this may not be your problem, the switch is an often unrecognized problem when the car will not start, but there seems to be power when the key is in the ACC or RUN position. Sometimes by pushing the "rod" downward when in the start position, it will move the slide just enough to make contact. A sure sign that the switch needs replacing or at least adjusting.

Good luck... GUSTO

jdubdeck

Sorry for the late response but you were 100% right! Once I got a new ignition switch in there she started up instantly! Thanks for all the help!

OzBeast

Great to hear jdub, I'm thinking I might have the same issue and was wondering if I could pick your brain.

So I also have a 75' and it has been running great for the 2 months I've owned it. PO took amazing care of this car, pretty everything has been immaculately maintained, just to set the stage.

Like you, I turned the key one morning and got a click. More specifically, a kind of clunk (like a relay?) from somewhere either in the steering column or center console area (hard to tell).

I tried resetting the seat belt override relay (75 specific) and gear shifter (neutral safety switch - NSS) to see if either were the culpret, and then it just started out of the blue. I had assumed it was the seat belt relay issue and carried on. A week later, luckily at home, clunk... no start. This time no amount of jiggling made it start. Tried bypassing the seatbelt relay with no effect (I think it is long disconnected), and the car won't start in Park or Neutral so I doubt it's a NSS (though I have a spare on hand in case it is).

Battery is 100%, fairly new and not draining at all. I have no reason to doubt the starter because after it failed to start the first time (but then came good) the starter worked flawlessly for a week before the car refused to start again.

So... long story short:

1) How did you test your neutral safety switch? I'd like to rule that out as it's easy access.

2) Do you have a good guide for getting to, and replacing the ignition switch? I've read as much as I can find on dropping the column, and have several reference books (AIM, Chiltons, Prince, Haynes), but none do a good job of explaining how the heck to access the switch!

3) Where did you order your switch?

Any and all help appreciated!

ps: Seeing as I haven't actually introduced myself on these forums yet, here is my baby...

pps: Don't let the flags confuse you, I'm actually from Australia :p

GUSTO14

#1 The easiest way to do a quick check of the NSS (on an automatic) is to put your foot on the brake, and with one hand turn the key to the START position while using the other hand to gently and carefully move the shift lever in and out of the PARK position and also the NEUTRAL position. If the starter attempts to engage as you move the shift lever about the Park and Neutral position, the switch is either bad or slightly out of adjustment.

#2 The ignition switch is located on top of the steering column, near the firewall, about even with where the toes of your foot might be. You should be able to see most of it by sticking your head into the footwell and with the aide of a flashlight look on top of the column. You can drop the column a bit if you want to, but with the aide of a mirror you can actually remove and replace it without dropping the column. Many times the switch is simply a bit out of adjustment and can be repositioned up or down the column and re-tighten the screws that hold it tight to the column.

#3 Most of the Forum vendors typically carry this switch and you may even be able to purchase it from a local auto parts store such as NAPA. Most of us have our favorite vendors, mine happen to be Paragon, ZIP and Wilcox simply based on past experience, but many of them sell the same items.

Are you at Maxwell by chance?

Good luck... GUSTO

OzBeast

Thanks Gusto, that's excellent info. I have a switch on the way from Eckler's now, just in case.

I read Jim Shea's papers on the ignition switch change and he advocates quite a process including steering column removal... glad to hear I may not have to go down that route.

I was hoping someone better with wiring diagrams might be have a multimeter test procedure for the NSS, but in the meantime I'll try your method.

Yup, at Maxwell for two years - good guess

GUSTO14

Staff or Student? What do you fly?

GUSTO14

Jim Shea definitely knows his stuff when it comes to columns. I've not yet found it necessary to completely remove the column to R&R the switch or adjust it. What I do however is lower it a few inches.

First remove the Lower Steering Column Cover

in order to access the Steering Column Mounting Bolts. Remove the two bolts and replace them with two longer bolts (2-3" in length) to support the column. Tighten them just enough to cover the threads in the nuts. Loosen the two nuts at the base of the column, but do not remove them The column will now drop down about 2-3" from it's normal position and allow much more visibility and access to the top side of the column.


Good luck... GUSTO

OzBeast

I'm a student at SAASS right now, flying a new book everyday Formerly however I was flying P-3s... which are about the same age as my Vette as it turns out.

That's outstanding! Great explanation. I assume the nuts for the Steering Column Mounting Bolts are captive, or at least part of the bracket above the column?

Beast

74modified

Good info on post #11, check that first, but before I would crawl under the dash, I would check that my starter/solenoid worked. You can check for power at the solenoid, or just jump from the battery lug and see if it spins.

jdubdeck

GUSTO beet me to the punch! It looks like he had some pretty good info. Let me give you some additional info that may help.

#1) Another easy way to test the NSS is to use a volt meter to measure the connectivity between the two wires that the switch connects to when the switch is in the "Park" position. Use the connectivity function or resistance function on your multimeter and touch the probes to the contacts on the two purple wires while the switch is in "Park" (the wires circled in the picture). If the contacts and the switch are good you should see the value of the connectivity function or resistance change. I tested mine this way because I didn't want to fool around with having my car lunge if it started in gear in my garage.

#2) Before you switch out the ignition switch you can check to see if the switch is bad. If you hook up the positive probe on a volt meter to the "S" terminal on the back of the starter and hook the negative probe to ground. You can try to start the car and see what voltage is getting to the starter. I read about 6V which is too low to kick over the solenoid. This is how I verified that the ignition switch was bad. I believe it should be reading 12V at the solenoid if the switch is good.

I added a picture of my ignition switch before removal to show you where on the column it is. I highly recommend dropping the column because it is nearly impossible to get the switch up over the rod that runs from the ignition cylinder to the ignition switch. I have added another picture and circled the nuts that have to be removed to drop the column about 2 inches which is enough to remove the switch. (Please excuse all the rust because my 75 is still in the works haha). When reinstalling a new switch make sure that you install the the white connector first because the black connector sits on top of the white connector.

#3) I was able to get my new ignition switch from Advanced Auto for about $16. The quality seems pretty good.

I hope all this makes sense. Let me know if you need any clarification. Good luck and sweet car by the way!

OzBeast

Jdub! Sorry about the late reply (busy Friday!!), just wanted to say thank you. Those pics are brilliant, I went from 'pretty sure' to 'completely sure' about what needs to be done.

This forum is outstanding, glad to be a part of it - hope I can contribute one day .

labhound

These posts are helping me also, I to have the same problem but I have a standard trans, the clutch switch is working and the only thing I checked with the ign switch was the continuity.
There wasn't any volts to the starter either, maybe a new one or try the "jiggle" test.

OzBeast

Thanks jdub, did the resistance check on the NSS and it registered so not going to change that out for now.

So in my stubborn stupidity I had convinced myself it had to be the ignition switch. Several hours of sweating upside down in Alabama summer heat, I had a new ignition switch installed. Hook the battery up... same problem.

I know, I know, I should have check the starter solenoid first, but I didn't want to jack the car up again - and my starter has heatshielding around it that needs to be removed and I was just being lazy. Well, that will teach me - the ignition switch took about 10x longer than checking the solenoid would have. Which will be tomorrows job. Sigh.