‘66 Cuda Won’t Turn Over - Only Got 6V at Switch

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clifftt

clifftt

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Help needed, have about 12 hours into this and getting more frustrated. I was using the starter relay under the hood to turn the engine over to adjust the valves after a ten minute run. I accidentally touched jumped the big stud and the small terminal together, now engine will not turn over. After 12+ hours, this is what I’ve got:

Good strong battery. New relay (three pole) which will engage/spin starter with big and middle posts. Older 4 speed which has no NSS. New electronic conversion kit with orange box.

Relay is getting 12.6v at the big stud at ON and START, but middle stud reads 0v when ignition switch is in “Start” position, and the small terminal on the relay only reads 5.5 to 6V in the “Start” position. When in “Start” position, fusible link gets hot and so does the brown wire going from the junction box to the ballast resistor.

What’s weird is the ignition switch. I pulled it and checked it with an ohm meter, getting normal readings directly from the battery: IGN1 and ACC 12.5v IN “On” position, IGN2 and STR getting 12.6v in “Start” position - so far, so good. Then I plug the ignition switch in under the dash, and only 5.5 to 6.0v is going out of IGN2. I have a spare, tested it, got the same results.

Ballast resistor and ign module both have continuity. I’ve been mapping this out on my diagram but can’t figure where the problem is. Welcome any assistance before I have the car towed somewhere $$$$$$$.
 
Sounds like you have a short in the relay lets call the solenoid feed terminal the "square" terminal

So you have the relay, MUST be grounded, as one end of the coil goes to the case

You have the small "push on" flag terminal, the yellow "start" terminal

You have the big stud which goes direct to the battery and is one contact in the relay

Last you have the "square" terminal, which is the other contact, and engergizes the solenoid when in start
 
Pull the "push on" wire off of the start relay and check the voltage in "start" on that wire, see if you get full 12V. If so, use a jumper wire and jumper the exposed "flag" terminal on the relay to the big stud If relay is good, should operate the starter. If shorted you may get smoke.

Otherwise you may somehow have the "start" wire shorted elsewhere
 
I checked voltage in the “push on” wire, only getting about 6V. Is it possible somehow the starter voltage is getting cut back by going thru the ballast resistor?
 
The yellow start wire only goes one place..........from the start terminal on the ignition switch to the relay

"It occurs" you could indeed have a short in the ignition line

You have two ignition feed sources, the "run" is IGN1 and is hot of course with the key in run

In "start, there are only two terminals that are hot out of the switch

That is, you have battery into the switch, and it start........

IGN 1 "run" is cold
accessory is cold
Yellow "start" is hot
and IGN2, (usually brown) the ignition bypass is hot. This wire goes from the key to the coil + side of the ballast. Maybe you have a short in that area, did you change something?
 
Sorry I work part time. Off to bed. Be at work tomorrow until after 3PM your time.
 
I don't know where/what the problem is. I'll type out some info that may help determine where the problem isn't...
You stated you were jumping the starter relay when you created a short circuit. So the ignition switch had to be in off position at that time to prevent starting. All switch contacts open stops any fault in the wiring right there. So switch itself is not the problem.
Why are you reporting reduced voltage on some wires in some switch positions?... Current can/does flow through the ballast resistor in both directions. There are 2 wires involved, a blue and a brown. Any time the ignition switch contacts pass 12 volts onto one of these wires you will find reduced voltage on the other of these 2 wires all the way back to the ignition switch.
there are other causes of low voltage... if your fusible link, any wire, or connection is fried to nearly open, you will see 12 volts, just not enough of it.
So get 12 volts into the ignition switch and out of it on the yellow wire, enough of it to energize the starter relay.
 
I did not change any part prior to the problem. After the problem I did put in a new relay, changed ignition switches (had a spare). I have full 12.6 on both sides of the fusible link, although it gets hot when key is in “Start” position.
Also did pull all three big plugs out of the firewall. None look burnt. Took a fine file to clean all the male terminals, hen plugged all back in.
 
clifftt said:
Relay is getting 12.6v at the big stud at ON and START, but middle stud reads 0v when ignition switch is in “Start” position, and the small terminal on the relay only reads 5.5 to 6V in the “Start” position. When in “Start” position, fusible link gets hot and so does the brown wire going from the junction box to the ballast resistor.
Click to expand...
The relay stud is always hot. It serves as a junction. Everything on that line is always hot. It will always be at system voltage.
If everythin gis wired right, it could be a bad connection. Not sure which terminal on the relay you mean. The one connected to the neutral safety (or whatever you've got) will read less than system voltage when current is flowing through. Should be ground or close to it.
See if this post and the two diagrams in it help.
Need help - no spark during cranking

Power flowing from the yellow start wire to NSS (or ground) internally connects the battery power (big stud) to the terminal going to the starter solenoid. I show that conection as an orange line in the illustration. That's internal.
 
Mattax, with the ignition switch turned to “On”, ammeter dropped to the first line. But when I turned the switch to “Start”, the ammeter pegs out to the negative.
I also measured the ballast resistor on both sides. Start side (which goes to the + side of coil): 0v “On”, 2v “Start”.
Run side (regulator side): 10v “On”, 1v “Start”. And I just noticed the plastic covers around both terminals plugged into the ballast resistor have gotten hot enough to start melting them. The brown wire from the resistor going into the junction box also is getting hot in the “Start” position, which goes to IGN2 at the starter switch.
 
There's a couple things you can do. This is surely a short "but where?"

Things to think about..........

Harness wiring often gets welded together when heated due to a short, causing crossover connections in the harness. This can do more bad things and really throw you off the track

One thing you can do to protect yourself is to put a series limiter in the battery ground lead. This can be a small auto -reset breaker maybe 10-15A or a big lamp, like an old headlight, or a stop/ turn bulb with the filaments wired in paralled. With such a thing in the ground lead, you can dead short the battery side to ground, and all it will do is trip the breaker or light up the light.

Check the yellow start wire for shorts to ground. Pull the connector off the ignition switch, disconnect the battery, and disconnect the yellow start wire from the relay. Check that wire to ground. Should be open.

Now check out the brown / bypass wire same way. Disconnect loads on the ignition buss. Pull the alternator fields off, pull the connector off the VR, disconnect your ignition system from the feed. Try to identify anything else fed by the brown bypass (ign2) when in start. Check that to ground with a meter

With your safety light in place in the ground lead, and the key held to start to "activate" the symptoms...........might need two people........try a wiggle test of various places in the harness. Under dash, under hood, etc, look for dimming of the bulb which indicates "you are close." Make these tests with the yellow start wire unhooked from the relay, and as much load as you can removed from the ignition buss.

Look the harness over for "melt damage" on the covering.
 
Wow, lots there to consider and chew on. I’ll tackle that tomorrow, Del. Thanks for the suggestions, I’ll get back to you hopefully tomorrow.
Easter weekend, family and friends are calling.
 
Do you hear a click when you turn the key to start? If not, put a starter relay on it. Simple ans cheap enough if that doesn't do it, you'll not be out much. Only a limited number of places the short can be. Switch, wiring, relay, starter. If there's no audible click from the relay, which it should do even with 6V, then I would chance a relay.
 
Before turning in tonight, I decided to do a visual check and found this: Pinched wire going to the “+” side of the coil, right under the valve cover bolt Where I was adjusting the valves. Bumping the starter at the relay didn’t cause the problem, not paying attention putting in one valve cover bolt caused the problem.
Humbled myself for doing something careless, but happy I found it before throwing in the towel.
Del, your comment about checking the brown bypass wire led me to the discovery. A late Mai Tai Friday salute to you and Mattax for your help!

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You are welcome. Jus' so ya know, my life's philosophy is

"You can't break it if it's broken but you can fix it so it can't be fixed." I've "fixed" a few things in my lifetime, including heavy duty shorts in wiring LOL

Maybe I WILL have a shot before turning in!!!
 
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