Intermittent no start issue???

[MI_Custumz]

I have a 1970 Monte that has an intermittent no start issue. By that I mean nothing happens with the starter, no click, no humm, nothing. I bought the car 19 years ago and it is getting a bit worse. All lights are working good. It has HEI on it as well as electric choke on the carb.

I have a new battery (2 months old) and it's good. Cables are about 3 years old and are molded ends, not the bolt on terminals. Here's what I have found so far and am at a loss:

Side mount battery with charging posts to fit the 2ga cables. Couldn't find long enough 2ga side post battery cables.

Grounds all show good with test light. Have one at the alternator bracket for battery cable as well as the fender one. Pad where starter mounts, core support, and engine block all tested good with the test light.

Starter tested good and looks good inside per a local rebuilder.

Previous owner installed a bypass from the IGN tab in the fuse block to the starter because he was having issues. There is an aftermarket ammeter with a 10ga wire and fusible links going from battery to gauge and back to junction block.

I did bypass the NSS and worked for a while, so I ordered one. Then went to pick up the NSS and it did the no start.

I tested some wires without the starter in (not a fan of the many start and shut off cycles). I got 12.59V at the battery, 12.59V at the junction block, 12.57V at the drivers side horn relay, 12.07V at the IGN tab in the fuse box, and 12.16V at the Neutral Safety Switch (automatic console shifter) in and out, 12.11V at the IGN wire to the starter, and 12.12V at the bypass wire to the starter.

I put a test light (tail light socket with wires) on the NSS output to see if it lights up when starting (either start or no start) and a wire from the starter solenoid to the inside of the car to check voltage with a multimeter.

Installed the starter and drove it yesterday. When I started it the battery tester showed 10.4V for low when starting and inside was 9.64V at the solenoid using just the key. Ammeter was just above 10 on the positive side before going for a 45 minute drive. Voltage per cigarette lighter plug in meter was 14.5V when driving. Got to my destination and shut it off. Waiting about half hour and started with key. Shut if off and waited about 10 minutes and tried again. It didn't start with the key the next 3 times with the key, but did with the bypass button setup. When the no start happened, the NSS test light lit up and meter said just under 7V at the starter (can't remember the exact number). The 4th time the key worked.

I am thinking I am losing some sort of connection from the NSS to the solenoid and possibly low voltage to the fuse box.

What steps can I take to get this fixed? I don't want a hack job, but am also limited on mechanical and electrical work. I am not  sure how to test stuff under load without actually starting the car up.

To prevent the engine from turning over and still test under a load, can I just unhook the wire going to the HEI?

How hard is it to remove the bulkhead to check it out, and what would I be looking for? I know it's a purple wire to the starter and from the NSS. The wires are all dirty and hard to tell which one the purple one is and I do have wiring diagrams but they look like a foreign language to me.

Once in a blue moon, the car won't start at all with key or bypass. I have a jump box I use and it sometimes works, but always starts if hooked to jumper cables or plug in charger/jumper in the garage.

Please keep it simple in explanation as I am not familiar with this type of stuff, but willing to learn. For example, "test under load" I assume means using the circuit like it should be used. Someone told me to test it under load without the starter in it and I didn't understand how since the starter creates the load. Then I got snippy advice and felt like just saying screw it and rolling with it as it was because I got frustrated. I did all kinds of testing for continuity and such as directed and told those tests were useless by the same person.

I am an empty nester and hard with work and chores around the house to schedule a time to get someone to come over and help. I have test leads and a camera I have been using to check stuff at the starter because I can't turn the key and see what's happening under the car at the same time.

I'll be willing to get what ever information is asked if I know how to gather it. Youtube is great, but sometimes it's not exactly what I'm searching for.

[420ponies]

Sounds to me that the ignition switch on the column could be the culprit. My ignition switch was bad when I got my Monte 20yrs ago. The "no start" then "start" thing happened numerous times with mine. Changed out switch, no issues ,except you make sure the position it's in stays the same. When you say Bypass, you mean an extra starter button, right?  If that's the case then you still have to use your key to turn the system on ,correct ? The ignition switch is located on the steering column, You will have to drop the column,(2  9/16" bolts) .there is a rod coming down from your ignition key that goes into the switch. 2 small screws hold this in position. When you turn on your key and go to start, does the key spring back from start position?  It might need an adjustment at that switch, (not going far enough to send power to solenoid). That's what happened to mine and new switch took care of it. I'm sure others will chime in to help you out with this. "Gremlin's " are the worst with wiring issues. Believe me, we don't get snippy ,we get to the issue at hand. Might put a pun in somewhere along the line, but all in fun. Hope this shines some light on this problem with your '70 Monte Carlo.

[MI_Custumz]

I have a new ignition switch in it. Well, a couple years ago. Seemed adjusted properly. I also forgot to mention the ammeter was just above 0 after returning home yesterday, so must have gotten high when charging the battery. Was doing lots of testing and wore it down a bit, but it’s still good. I was thinking of maybe taking the test lead for voltage readings at the solenoid and hooking it to the top tang on the NSS and moving the connector down so only the wire from ignition is on it. Basically IGN to NSS and test wire from NSS out to solenoid instead of IGN to NSS, NSS out to bulkhead, bulkhead to starter. That would eliminate the stock IGN wire from the equation. Not sure if it’s a good idea. 

[Scott S.]

Adam,

This might just be a wild guess, but is there any corrosion on the battery cable ends ?? And do they fit tight ?

Couple summers ago Montelishi started doing something like that. I'd stop at a store/gas station, and when I went to start the engine.... nothing.

Found it I twisted the connections to provide clean contact, everything worked again. Replaced the ends and was good until the battery died (another story) ....

Good luck, Scott.

[MI_Custumz]

Battery cables and connections look good. I did get “universal” cables from Autozone because I wanted 2ga wires. Found out they are a tighter fit for the positive post vs the negative post. Found that out with a micrometer. I have two “positive” charging posts in the side mount battery screw holes so the actual negative is tight with the negative cable. The positive cable stays on and when I go to drive the car, I put the negative cable on and snug it down, but not crazy tight. I’m leaning towards a wiring in the ignition circuit, but definitely open to advice and opinions. 

[72 Monte Carlo]

I agree with 420ponies, in that it sounds like the ignition switch on the steering column is failing or is not adjusted properly, or the rack and pinion between the ignition key cylinder and the ignition switch is at fault.

[MI_Custumz]

Ignition switch is only a couple years old. I could remove it and inspect it. Possibly adjust it. When I installed it, I made sure it was adjusted according to what I found online. Would it need to come back more so the key forward pushes the switch more to full power? ACC, off, run, and start all seemed to slide into positions as it should. My first step when I tinker with it again will be check the ignition switch.  It has to be something simple, just narrowing it down is a pain. If I don’t get if figured out by end of the month, I’ll prep it for storage and tinker with it then. Not going to start it while up for the winter. 

[72 Monte Carlo]

I would readjust the ignition switch and see if that fixes the issue.

It sounds like the switch needs to be moved towards the steering wheel more if it's not fully engaging the start position of the ignition switch when the key is pressed all the way forward in the start position.

[Chevy Dave]

I had the same issue, it ended up being a worm sector gear and rack in the steering column. The rack and engagement  rod would not travel far enough to close the start contact in the ignition switch.

[stangeba]

This reminds me, back in about 1982 when my 71 350 wouldn't start at times. The starter would NOT spin but I don't remember if it made a clicking noise or not. One time it did this when I was leaving the Buick dealership I worked at and one of the mechanics brought out a hammer, opened the hood and hit the starter motor one or two times and then it cranked and started fine. The starter needed new brushes, and then all was well. The brushes were very very worn out so they didn't even touch. This starter mtr was original to the car and never touched till then.      Could anything with the shifter be to blame???  Hold the shifter tight into Park, while you try to start it?

Good luck!

[MI_Custumz]

I am going to try to adjust the ignition switch next time I mess with it. It's not the starter. Reputable rebuilder opened it and said it's in great shape. I asked if he would rebuild it and he said don't bother at this time. Most places would take your money and say that it needed it.

 

What is the worm selector gear and rack?

[72 Monte Carlo]

They sit inside of the column right behind the ignition key switch and they operate the rod that moves that ignition switch

[Dtret]

Column breakdown 

[MI_Custumz]

That appears to be the key lock diagram. Nice to see it, but think the ignition switch is on the column and left out of that photo.

I have "BATT" on the HEI cap. If I were to unhook that wire, can I crank the car without firing it up to check voltage at the starter? Will it cause any issues by just having the starter turn the engine and not starting? Really don't want to drop the starter again to check cranking voltage.

A thought I had was to try this, but not sure if it would be a good test. The connector that goes on the NSS has a top and bottom female connector (one molded connector with 2 slots). Top is power (would have to verify it again) from the ignition and the other goes to the starter. Could I just move the connector down so the top female is on the bottom male and that leaves the top male tab open. Then hook the wire from the solenoid to that open tab? NSS should work if power is in top/out bottom or in bottom/out top from my understanding. That would be basically key to NSS, NSS right to starter. Bypassing bulkhead and original starter wire.

[420ponies]

Yes, you can disconnect that wire going to the HEI . That wire is 12v to the ignition from your switch. Oh, and I have done the worm sector gear,  not something I'd do again (only if I had to). I do have a question though, is this a console shift car or column shift car ? If it is a column shift, it might not be going into the position for the neutral safety switch. that's why Bruce asked about the shift arm.

Edited September 6, 2024 by 420ponies
added content

[Dtret]

1 hour ago, MI_Custumz said:

That appears to be the key lock diagram. Nice to see it, but think the ignition switch is on the column and left out of that photo.

I have "BATT" on the HEI cap. If I were to unhook that wire, can I crank the car without firing it up to check voltage at the starter? Will it cause any issues by just having the starter turn the engine and not starting? Really don't want to drop the starter again to check cranking voltage.

A thought I had was to try this, but not sure if it would be a good test. The connector that goes on the NSS has a top and bottom female connector (one molded connector with 2 slots). Top is power (would have to verify it again) from the ignition and the other goes to the starter. Could I just move the connector down so the top female is on the bottom male and that leaves the top male tab open. Then hook the wire from the solenoid to that open tab? NSS should work if power is in top/out bottom or in bottom/out top from my understanding. That would be basically key to NSS, NSS right to starter. Bypassing bulkhead and original starter wire.

The photo was intended to show the tumbler, worm gear and selector and how it all worked. 

[MI_Custumz]

9 hours ago, 420ponies said:

Yes, you can disconnect that wire going to the HEI . That wire is 12v to the ignition from your switch. Oh, and I have done the worm sector gear,  not something I'd do again (only if I had to). I do have a question though, is this a console shift car or column shift car ? If it is a column shift, it might not be going into the position for the neutral safety switch. that's why Bruce asked about the shift arm.

It's a console shift car. I have a tail light socket wired to the output on the NSS and it lights up if the car starts or not when the key is turned to start. That's what leads me to believe the issue is from the NSS to the starter unless it's losing voltage to the NSS, but the light doesn't seem to dim when it's a no start.

[mikeco]

I’m having the same issue with my 70 console shift car. New starter new ignition switch new battery and still only getting 6 V when turning the key on my wire going to my starter has anybody come up with a solution for this problem?

[MI_Custumz]

I got it figured out I think. Put a new negative battery cable on. It looked good and whatever I tested with a multimeter for continuity and stuff tested good. So far, no issues. 

[klassic rob]

check the horse shoe bracket that the NSS switch tab goes into, i have had the same issue with my 70, replaced everything once , starter twice including battery cables work for a bit then not, i figured it out just by chance, i thought i had the NSS switch correct used alignment hole, start then wouldn't pushed the shifter all the way forward in park held it forward car started everytime. adjusted NSS switch bolt holes are slotted, currently no issues since then

[Scott S.]

21 hours ago, klassic rob said:

check the horse shoe bracket that the NSS switch tab goes into, i have had the same issue with my 70, replaced everything once , starter twice including battery cables work for a bit then not, i figured it out just by chance, i thought i had the NSS switch correct used alignment hole, start then wouldn't pushed the shifter all the way forward in park held it forward car started everytime. adjusted NSS switch bolt holes are slotted, currently no issues since then

Would make a good anti theft system.