help with freakish non start problem
 

I can't for the world of me figure out what to try next. First the back story.
I drive my 82 SC into the driveway at night with absolutely no problems. Turn it off, again no issues running or stopping. Come back a few days later, turn key and the engine starts to turn about a 1/4 crank then stops. No drama just stops. So turn key again and nothing but a small click from the solenoid.
I check the battery. It's fine, fully charged and showing 12.6 Volts.
I replace the electronic part of my ignition switch just because it was really old and while I was trouble shooting this I didn't want it to fail at sometime in the future.
Check the voltage at the solenoid and it's getting 12.4 volts from the yellow terminal 50 wire from the starter. Remove and clean ground strap.
Try again and no start. Figure it must be a bad starter. Replace starter. Same thing, no start. Pull starter and check flywheel ring teeth. Fine, all there. When I try and start it there is no dramatic sounds. No grinding, no high speed spinning. Nothing but a click and hum.
I'm at my wits end as to any direction to check next. Never had this problem before.
Please help

Steve

Sorry. I should have mentioned that the battery is new and that I had it load tested as well. it checked out fine.
Thanks Jared. And the mystery continues............

Can you turn the motor over by hand or is it bound up?

Thats next on my list.
I am kind of dreading trying to turn it over, just because for the world of me I can not figure out how it would freeze or seize just sitting for a few nights. There is the right amount of oil in the trans and engine and was not running hot or any problems when running last.
Please keep the ideas coming

red wire to the msd or whatever ignition you might have?

OK
So the car is in the air. I took a deep breath and the engine turns freely. Put it in gear and the engine and trans turn together fine.
Which red wire?

Here is a great troubleshooting procedure for a non-start:
Pelican Technical Article: Starter System Troubleshooting

Just follow it and you will find your issue.

You didn't say if you had 12.4 V to terminal #50 while trying to use the starter? There must be a load on the circuit for the test to be meaningful.

Yes I have 12.4 volts to the 50 terminal on the solenoid while trying to crank.
I just tried to jump the car incase the battery test was wrong but I had the same results
I know the battery is good.
I know the starter solenoid is getting 12.4 volts.
I have cleaned the ground strap
I have a new load tested starter
The starter makes a noise but does not engage.
Also this is the second starter because my friend dropped the first new breaking off the solenoid one when I pulled it to check on the fly wheel ring teeth. I had to buy a second one

Try attaching the ground clamp of your jumper cables directly to the starter body. Does it crank now?

What about the big red wire carrying +12 directly from the battery? What is the voltage on it when cranking? Could it be shorting somewhere? Like in the alternator?

One thing that is easy to do is to run jumper cables from the battery directly to the starter. Clamp the negative cable to the frame of the starter and the positive to the big connecting post on the starter and see if the starter spins when you jump the positive lead to the starter solenoid. If it does, you have a bad cable running from the battery compartment to the starter or maybe a bad ground right at the battery. You can do this with long jumper cables or move the battery next to the starter.

I would try cleaning the ground strap connections again, use some sandpaper and clean the body surface and the connection so that there is no corrosion. Clean both ends of those connections down to the metal.

Good Luck, Shane SmileWavy

So.......
I've got 12.45 volts when measuring directly terminal 30 on the solenoid (power from battery) before cranking.
When I crank it the voltage drops to 0.65 then when I stop cranking it goes back to 12.45
I can hear the solenoid engage but the motor does not spin.
What next guys?

I will try grounding the trans directly to the body with a jumper cable next to eliminate that

I'm thinking that's it.

On mine, I ran a second ground (just one from a local franchise auto parts place) from the body by the trans (the same bolt as the stock strap) to the top starter mounting bolt. (It's been a while, but I think it might have been a Warren Hall suggestion.) That solved a lot of starting problems for me.

Good luck,
Shawn

If I had a bad ground right at the battery wouldn't everything be effected?
Could there be a short somewhere in the alternator?

There's a condition known as "high current density" which describes what may be affecting your car. Somewhere along the electrical path is a corroded connection which is trying to pass more current than it is able. Voltage will read normal but not enough amps can pass to do the job you need. Connecting directly to the battery from the starter will rule this out. Just set a second battery on the ground next to the starter and hook the jumper cables directly to the starter. If the starter starts and the car runs you know the problem. I have had to do this before and it told me the problem. The battery in the car can pass enough current to the other electrical parts to run them but not enough to turn the biggest consumer, the starter. It isn't the battery's fault but rather some weak connection along the electrical path. Chevy trucks with side posts on the battery are famous for this problem.

White crusty corrosion inside the terminals, or a bad wire connection inside the terminal, or a battery that has given its all.

Rex is right on.............
 

Rex is right on...I just went through this with my 73.................and the 71 before it....Attach a jumper cable from the ground point that the battery negative attaches to (chassis ground) and then back to the starter flange...or closest ground point..............I'm betting it will crank.

Regards,

Al

PS: then replace the ground strap, clean all chassis ground points etc...

I'll take "bad ground" for 500 Alex.

^^^^ This.

Check your grounds first, if that doesn't do it, then my vote is to clean the 14-pin connector in the engine bay and the connector where the ignition switch harness plugs into the firewall.

Something is passing voltage but it isn't a good enough connection to pass the current you need.

what happens if you jump terminal 50 to the battery cable positive right at the starter?

here's the latest from this morning
So I grounded the starter directly too the body with a jumper cable.
Same thing, solenoid clicks starter doesn't turn.
Grounded the trans directly to the body, same results.
Hooked the starter up directly to another battery and it spun like a mother.
So I figure it's not getting enough juice from the direct red wire powering the starter as I have

1-eliminated the yellow wire as fault as it is getting 12.4 volts and the solenoid clicks
2-eliminated the ground problem by bypassing the ground cable and grounding the starter directly to the body
3-eliminated the battery not putting out enough juice by buying a new one and having it load tested
4-deduced that the problem must be lack of enough voltage to power the starter at terminal 50


Comments and directions are appreciated
Thanks
Steve

you said the yellow wire (terminal 30) was dropping to .65 volts when cranking, is that still true?

are both battery terminal clean?

is the body ground clean at the battery?

you cleaned both ends of the body to engine ground strap?

the solenoid requires a lot of current to pull in. even though you have 12v at the yellow wire, there can be resistance somewhere reducing available current.

while cranking, measure battery voltage, battery voltage at the starter and voltage at yellow wire. (yellow wire connected to starter)

do you have a car alarm?

Where did you connect the extra battery? To terminal #50? Or to the big red wire? If the big red wire, then the red wire going from the battery to the starter is your problem. There is either a bad connection on one end, or the wire itself has broken - possibly at a bend? Are either ends bent or do you have questionable terminals or connections?

If the problem is at terminal #50, you may have a bad ignition switch.

Steve,

If you think it is the red wire just use some leads and test it.

I think that the jumper cable may not be giving a good ground. You need serious clean, metal to metal contact.

I have been through a similar situation with a couple of electrical gremlins, my clock didn't work, my starter started intermittently crapping out on me, my light switch went crazy. My fuel pump would turn off, etc. After throwing about 100 hours of time and 1000 dollars, I had a bunch of new parts, but still had the same issues.

I had simply checked my grounds and tightened them down, so I had previously eliminated that as an issue.

Then one day I removed a ground strap and scraped off all the gunk and residue , I sanded all contact surfaces down to metal, and all my problems went away, and my car ran smoother.

I listed this as a priority for annual PMCS (Preventive Maintanace Checks and Services).

Car alarm/ disable?

Thanks everyone
Let me try and answer everything. There is no car alarm. The battery is new and all posts and connections are tight.
Wouldn't the grounding from the jumper cable be enough to get the starter engaged if there was enough juice? It is a brand new ignition switch and when it turns the solenoid engages
I hate electrical problems

Can I just jump from the positive side of the battery to the 50 terminal on the starter without doing anything else and shouldn't the starter spin if it is grounded correctly? And would that not prove the problem is with the power from battery to the 50 terminal the problem?

Yes - so which test did you do that got the starter to spin? Connecting directly to terminal #50 on the starter?

The starter switch wiring goes through several connectors that can be bad all the way to the back of the car and if the car has A/C there is a relay that can cause problems.

Work from the rear of the car forward, start at the 14 pin connector under the plastic cover on the driver's side rear engine compartment . Then move on to the the plug behind the heater blower. There are relays on your car to turn off the A/C and heater blowers when the key is in the start position to save power for the solenoid load. The electrical part of the switch can fail, and the mechanical switch can fail separately, then it is time to go for a push button.

I actually jumper directly to the cable coming out of the solenoid (connected to the 50) into the starter motor housing from another battery.
There is no AC/ heat etc in the car.
I am getting 12.4 volts right at the yellow wire on the solenoid with the starter switch on so I don't think there is any reason to suspect the starter switch or wiring back to it. If I didn't get 12.4 volts there I would trace back and find the problem, but since I'm getting 12.4 I figure that is enough to work the solenoid and when I engage the starter directly it spins so I have got to figure it is the power from the battery to the starter

If the starter turns with a separate supply of power, then there is nothing wrong with the starter. It's got to be something wrong with the big red wire going from the battery to the starter. Could it be touching something? Partly melted somewhere? Bad connection at one of the terminals?

is the yellow wire connected to the correct post on the solenoid?

what type of connections do you have at the battery? IE, are they original, are they the type that clamp to the cable? how do the cable ends look? any corrosion on the cable going into the connector?

is the solenoid pulling in with the ignition switch? do you hear a click?

all these tests should be done with the battery that is in the car. this extra battery is confusing. im not sure if the good results are with the extra battery or the one in the car.

whe you say "engage the starter directly" are you jumping from the battery cable over to the yellow wire? and, the car starts as it should? or, are you jumping over to run the starter motor only?

Solenoids are the usual culprit with these types of starting difficulties, exact same thing happened to me with my Expedition, I bench tested the whole unit and found that the solenoid was not triggering the starter. I replaced the starter and the problem was solved.

So I'm pretty sure I found the problem. I powered the starter with a cable from the cars battery. Turned the key and it started.
So I obviously have a problem in the red wire running from the battery to the starter. No to start tracking that down

Post a picture of the positive battery terminal, wire usually goes bad-corrodes-right at the terminal. You can just replace the battery terminal and clean up the wire.

New battery and new cables

^^^ What he said.

They can also be intermittent.

Thanks everyone.
I think I have found the problem. It was two fold.
First there was a lousy connection from the power supply side and now I need to replace the trans ground strap.
Should have it finished tomorrow

I'm back.
Rewired the power supply side. Tested by running cable from starter to ground and the car started right up. Removed what looked like a perfectly good ground strap and cleaned the mounting points. Installed new ground strap. Car started right up. Buttoned everything up, put tires back on dropped car off jacks. Get in ....................................... car wont start. Same problem and same sound as when I got on this merry go round a few days ago.
I hate electrical but this is nuts.
Any idea's why the car would run the two times it was on jacks but would not run as soon as it was off jacks.
I raised the car up from the engine sump plate and supported it by the torsion bar covers
This is driving me nuts as I had plans for some driving this weekend

Thanks
Steve

Explain "rewired the power supply side"
You ran a new wire from the battery to the starter?
Also what cable did you run from starter to ground?

After I replaced the ground strap the car started.
Now it will not, so I ran a jumper cable from the starter to the body ground by the trans. Turned the key and nothing.
So I figured the new ground strap was good.
Then I ran a jumper cable from the battery to the terminal 30 direct. Turned the key and no start.
Then I ran the jumper cable from the battery directly to the field starter winding coming out of the solenoid and the starter spun like it should. This also proves that the ground strap is good because I did not ground the starter any other way
My "assumption" is that it is a bad solenoid, but what confuses me is it started up fine after I replaced the ground strap and it was on jacks.
I know I was getting 12.4 volts at the yellow wire at terminal 50 from the ignition switch when turning the ignition and I know I'm getting and I know I'm getting 12.4 volts to terminal 30 because I ran it direct from the battery so the only thing I can assume is the solenoid is intermittent or bad.
Does anyone know how much draw (amps) the solenoid needs? It can't be a lot as it is only a ten gauge wire