No power to the solenoid?

[sixt9x33rs]

When I turn the key on my car it acts as if I am trying to start the car without the clutch depressed. I have a known good starter, and solenoid. I want to take a few voltage or amp tests in the system to try and find either a bad connection or part. Any suggestions are welcomed.

Thanks

Lawrence

[rich69rs]

Sounds like perhaps an ignition switch problem.  Solenoid shouldn't see any voltage until the ignition switch is turned all the way to the "start" position.  If car is trying to start with the ignition switch in the "on" position, I would look closely at the ignition switch.

[sixt9x33rs]

Rich do you know of a way to isolate the ignition switch to see if it is faulty?

[L78 steve]

Your problem could be anything including the battery. Do a volt reading at the battery when you turn the key first. Then do a volt read at the starter solenoid purple wire.

[My68SS]

Richard, I'm reading Lawrence a little differently.
Lawrence, is it the case as suggested by Richard, that when you turn the key to the 'on' position only, that the starter motor engages to crank the motor, or is it that when you turn the key to the 'start' position, the starter engages but struggles to crank the engine?
If it's the latter, then connect a voltmeter across the battery terminals - should read around 13 volts, then with the meter still connected, turn the key to 'start' - voltage should only drop to around 8 volts. If it drops significantly more than this, then suspect a bad battery.

Best to have someone else turn the key while you hold the meter leads directly on the lead posts of the battery.
If volts are ok, then it must be a bad connection, either battery terminals, neg at engine or pos at starter motor, though these types of problems 'usually' make the starter solenoid rapidly click in and out as well.
From your description, my money is also on the battery. Good batteries have been known to suddenly go high resistance in one cell, for no apparent reason.

[sixt9x33rs]

Thanks guys I appreciate it. Will try the easy stuff first

[mikefam]

I'm in the middle of troubleshooting the same problem. Mine would fail occasionally and mostly gave me trouble when the engine was hot and recently it stopped working altogether. I think that I traced my problem to a combination of old dirty connections with the worst of them being in the console wiring harness to the neutral safety switch.

The problem is that not enough power is getting to the starter solenoid to activate it. This can be caused by a weak battery or one or more bad connections between the battery and the starter solenoid switch.  It can also be a bad connection between the body of the solenoid switch and the negative battery post.

After studying the wiring diagram I learned that the starter solenoid circuit is as follows:

1 fusible link from battery + to terminal post on the radiator support near the battery.
2 wire from terminal post to horn relay
3 wire from horn relay to the bulkhead connector on the firewall behind the power brake booster
4 wire from the bulkhead connector to the ignition switch
5 wire from ignition switch to the neutral safety switch in the floor console (auto transmission)
6 wire from the nuetral safety switch back to the bulkhead connector
7 wire from the bulkhead connector to the starter solenoid

Any and all of these connections can get dirty and cause resistance in the circuit that adds up to a problem.  Or as stated previously it could be as simple as a weak battery or bad battery cable connection.

Happy hunting and I'd love to hear what you find, ,Mike.

[mikefam]

I forgot to mention that it could also be a bad starter solenoid switch.

Mike.

[Stingr69]

Mikes post is very comprehensive.  Best way to go through the system to find the issue.  Did that a few times over the years.

If you are not a "Concours" type of Camaro owner, there are other ways to solve the problem for good. Purists need to stop reading now.

Added a Ford starter relay and never ever had a problem again.  Requires no cutting of original GM wires in the harness. 

Relocate the end of the GM Purple wire from the "S" terminal on the starter to the "S" terminal on the Ford relay, Make up a 12 Ga wire from the big hot red starter terminal to one of the big Ford relay terminals, make up another 12Ga wire from the other big terminal on the Ford relay and attach it to where the GM starter Purple wire used to be. Done.

Purple wire triggers Ford relay (still works even with low voltage),  relay gets full 12V power from existing battery cable (bypassing all the voltage drops) ,  Relay sends a true 12V to the starter "S" terminal and away you go. All the neutral safety functionality is still there.  This is an automated electrical "Screwdriver across the terminals" solution but less dangerous.  Great easy place to attach your remote engine bumping switch for setting valve lash too.

UGLY? yes, but I am DRIVING, not troubleshooting a marginal from the start 45 year old electrical system.

Just another way to go if you have a driver car.

[mikefam]

While replacing the relay like that will work it is probably just buying time until the original problem worsens and fails altogether. If it is the ignition switch for example the switch will eventually stop working altogether. Besides, I have had the car since the 80's and managed to keep it looking stock, I did change the L6 for a 327 motor because I didn't want to drive the 6 banger but I still have the original engine in the garage.

I already have the dash gauges and ignition switch removed and the floor console is opened up. I found the connections on the horn relay to be so rusty that I had to dremel one off, I found moisture in the bulkhead connector and I found an intermittent connection in the floor console. I am replacing the ignition switch with an Echlin that cost about 20 bucks, the wiring harness cost about $40 and I found an OEM horn relay for $50. My plan is to never have this problem again.

I just received a new console harness from Heartbeat city and will spend some time with it this afternoon.

[sixt9x33rs]

I have yet to have the time to work on my car, but hopefully soon. Mike thank you for the detailed description of the wiring diagram.

[mikefam]

Happy to give back to the group, I've come here for help many times through the years. The reason I'm able to describe the starter circuit so well is because I've had my head in the book for days trouble-shooing my own.

I think that today I finally got to the bottom of my problem. After installing the new horn relay the starter is working again. I'll install the new harness in the console tomorrow and that should do it for me. I can't say that it was any one thing that cured my problem and I think that I had a few bad connections that I corrected. In hindsight I think that the bulkhead connector and horn relay that were the biggest offenders.

Mike.