c2 (1967 Small Block) Starter Solenoid Question

[Paul S.]

Hi All,

I found this post by John Hinckley that describes my issue to a tee.

https://www.forums.ncrs.org/showthre...524#post221524

My car is well tuned and a new Holly carb last Spring (the 3810 which Long Island Corvette Parts and others sell). Choke, fast idle cam and all the rest check out. I've owned this car since 2010 and got the starting symptom John described in his post once in awhile.

When starting the car, it just seems to crank with no indication it's going to start and then you turn loose of the key and it fires. It's now gotten to the point that two out of the last three times I've tried to start the car, it does the crank, crank, crank, forever until the battery runs down (literally) and it's acting like nothing is firing and doesn't fire off when I release the key. The one time out of the three it did start, it just started like it should (push the accelerator down once, turn key and start).

So my question is, how do I go about checking to determine that I have or don't have an open circuit on the starter selenoid, and if I have that is that just a matter of replacing the selenoid. Thanks.

Paul

[Steve G.]

Re: c2 (1967 Small Block) Starter Solenoid Question

You connect a voltmeter to the + side of the coil and read it while cranking. It is also possible, (even likely) that you have an ign switch problem. With the ign switch in the crank position you should still have reduced/running voltage to the coil and in most circumstances they will start on that.
Steve

[Paul S.]

Re: c2 (1967 Small Block) Starter Solenoid Question

You connect a voltmeter to the + side of the coil and read it while cranking. It is also possible, (even likely) that you have an ign switch problem. With the ign switch in the crank position you should still have reduced/running voltage to the coil and in most circumstances they will start on that.
Steve

Ok, sorry if this is a dumb question, what reading should I see on the voltmeter that tells me "good" or "bad"?

[Steve G.]

Re: c2 (1967 Small Block) Starter Solenoid Question

I don't know without looking it up for the key on, not cranking voltage, but somewhere around 8 volts would be right. Cranking voltage should be the same as batt voltage. So connect your volt meter to your batt (at the alt is easiest) and take a reading while cranking. That's the voltage you should read on the coil + when cranking.

Steve g

[Paul S.]

Re: c2 (1967 Small Block) Starter Solenoid Question

I've got an AC car with the battery on the driver's side and connected to the battery with my Equus 5568 timing light/multi-meter and I was getting readings of 9.4 volts cranking and at the coil it was tougher to get any reading because the car decided to start right up but when it was reading while cranking it was sporadic (may have been a connection issue with the meter) and less than half-4 to 5 volts. Also, when I shut the car down and tried to restart, I hear a single click and the entire car goes dead (meaning no interior lights, no clicking of the key like a car with a dead/weak battery sounds). Wait a bit, and car starts normally. And by normally, I mean starts and idles at 575 rpms as nice as can be.

It's raining today so I cannot move it and my other cars to be able to do much right now, but I'm guessing that if the power to everything is being cut, that's the ignition switch or something else not the starter solenoid--is that right?

Paul

[Steve G.]

Re: c2 (1967 Small Block) Starter Solenoid Question

If everything is going dead (head lights etc) it is battery cables or battery, most likely dirty cables.

Pull the ht coil wire from the dist cap and ground it out to prevent it from starting (grounding prevents voltage spiking). Connect your volt meter to the coil + and turn the key on. Read the voltage. Crank it over on the starter and read the voltage while you're cranking.
Steve

[Paul S.]

Re: c2 (1967 Small Block) Starter Solenoid Question

Well the no power I think is the battery cut off switch (the kind that has the knob you turn) that had a bit of corrosion--I took it completely off which in and of itself turned out to be a job because I had to take off the battery hold down bracket to reconnect the negative battery terminal. And that's a lot of fun putting the bracket back on (reproduction piece that's not quite right so you have to get the rods positioned perfectly which is hard to do from the top side). I'll wait for a better weather day, when I can move my cars around to check the voltage at the coil.

[Richard M.]

Re: c2 (1967 Small Block) Starter Solenoid Question

Paul, Important data to help diagnose your issue. What is your ignition system?

Stock points system....

K66 Transistor ignition....

Aftermarket ignition.... (Pertronix, MSD, Other?)

Also, is there any other load on the IGN circuit other than the stock load(s)?

Rich

[William F.]

Re: c2 (1967 Small Block) Starter Solenoid Question

Could be batt cutoff switch-I've had that happen. Could also be infamous firewall connectors. Lot of sphincter tightening fun when lights, engine, and everything go out at night due to corrosion on these connectors. Don't ask me how I know.

[Paul S.]

Re: c2 (1967 Small Block) Starter Solenoid Question

Totally stock ignition system, points. I am virtually positive the total power loss is the battery cut off switch as it's not been an issue now that I took the cut off switch off. The weather has been rotten so I haven't been able to work on the solenoid/starting question since last weekend.