Need help Diagnosing non-starting

[dabald]

Hi guys, I need your help diagnosing a starter issue: 80 811SC - Car just won't start out of the blue... - I've got 12.6 V at the battery and on the yellow wire at the solenoid - The V does not drop at all when cranking - The solenoid does not click when being cranked - I can push start it and she runs fine - I was going to try to use some jumpers under the car on the starter but the third time I sent sparks a flying I stopped, LOL... I "think" the solenoid / starter is bad but before I go thru pulling it off I want to ask you guys what you think? I see that one bolt to the starter is on top and way back there... I don't want to go thru the nightmare of pulling it just to bench test it and find out it's something else. Also, the ground at the battery looks good but I could not find the ground from the transmission as I've read other's post refer to. Any help locating that tranny ground or your starter diagnosis would be greatly appreciated!

[Bob Kontak]

Have you tried the whack the solenoid trick?

I am assuming when you use the term "cranking" that means you are turning the key to the start position and nothing is happening.

The transmission ground lug is on the passenger side of the body near where the transmission gear selector shaft enters the cabin. It is a boss about 1" in diameter. It is essentially a metal plug welded into the body.

I stole this picture from paulsgarageblog.com

[pete3799]

Don't assume the grounds are good just because they look good. Clean them.
The trans. to body ground is at the front lower passenger side of the trans. the nut is accessed from going in just above the trans. support. (long extension)
Usually the solenoid will click with a bad ground.
Try rapping on the solenoid with a hammer some times this will free it up.

[dabald]

Thanks guys! YES, I did try whacking the solenoid with a screwdriver and then with a hammer. Now that I know where that tranny ground strap is, I will pull the ends, sand to bare metal, clean and re-assemble. Yes, when I said cranking position I meant "Key-on" as if starting the car. There was no click at all... I can hear the fuel pump run and that's it... Keep the diagnosis coming guys, BIG thanks for your thoughts!

[dabald]

Thanks guys! Yes, I whacked the solenoid with a hammer... Yes, cranking position was with my wife at the key trying to start it for me while I was underneath next to the starter. I appreaciate the picture and description of the tranny ground strap! I'll preventatively clean that bad-boy up next!

[T77911S]

Originally Posted by pete3799

Don't assume the grounds are good just because they look good. Clean them.
The trans. to body ground is at the front lower passenger side of the trans. the nut is accessed from going in just above the trans. support. (long extension)
Usually the solenoid will click with a bad ground.
Try rapping on the solenoid with a hammer some times this will free it up.

+1
grounds. very important and very often overlooked as the problem. dont forget to clean the ground at the battery and both terminals.

[al lkosmal]

Also,
+1..often this is the transmission ground strap, but I've also had the yellow wire to the solenoid come off. You might check that too.

regards,
al

[boyt911sc]

dabald,

Cdnone1 (Steve) has undergone extensive tests for electrical troubleshooting and successfully found the culprit for his non-start problem ('82 SC). He could help you and share his work. He's now very familiar with the electrical connections from ignition switch to starter. But it looks like your solenoid is not working at all.

Tony

[dabald]

Monday update - Today I picked up a new starter and solenoid from my engine builder. It was a dirty mess to change but got it done in about an hour... No change! OK, so tomorrow I'm going to try finding that ground from the transmission to the body. Bob Lontak posted a nice picture and description but I could not find it today, albeit I only spent a minute or two looking since I had the new starter and I really thought that was the issue...

One other piece of the puzzle that is posibly relevant. When this no start issue happened, I was at the end of replacing the master cylinder. I replaced the MC, bled all the brakes and then went to start it when she wouldn't kick off. Is there possibly anything near the fuse block that is ignition related that i could have bumped? I don't think there is a starter solenoid, is there? There are no blown fuses... There was a small wire up under the nose of the MC by the dash that looks like I might have pinched. I just removed the master cylinder again but ran out of light in the carport. That little wire had the insulation holed and a little copper shiner showing. I'm going to check it for continuity tomorrow and then either re-splice it back together or wrap it in heat shrink.

Boyt911sc, I appreciate your idea, I may contact Steve after tomorrow's "after work and coaching" diagnosis...

Keep the ideas coming guys, I really appreciate your brains and your time!

[dabald]

My bad, in the middle of my last post in the second paragraph, I meant to say "is there a starter RELAY in the fuse block?" I did not mean "is there a starter solenoid in the fuse block..."

[pete3799]

You state that you got 12.6 volts on the yellow wire at the solenoid when your wife held the key in the start position. So the ign. switch works- the yellow wire has continuity- only thing left is a bad ground.
It's a good idea to rotate all the fuses in there holders to assure that there is no corrosion preventing good current flow.

[boyt911sc]

dabald,

The symptom of your problem is very similar to that of Cdnone1's no-start problem for his SC. Voltage at terminal #50 (solenoid) was always present indicated by volt meter and test light when the ignition switch was turned to start but starter didn't turned at all. Suggested to him a series of tests that finally identified the culprit. If you like to contact him, PM me and I'll provide you his tel. #. HTH.

Tony

[dabald]

Tonight, I found the ground strap to the body from the tranny. I completely sanded and cleaned the connection. I did the same with the ground at the battery. I confirmed I have 12.5 V at the battery, at the starter and also on the yellow/stripe wire, top blade, on the starter when the key is in the cranking position. There is NO clicking of the solenoid when I try to crank it. This is a brand new Bosch starter and solenoid, zero miles on it. I had nicked a wire under the nose of the master cylinder during the master cylinder replacement. Tonight I skinned back the insulation, cut, and re-spliced the wire back together.

[Cdnone1]

Did that solve your problem?
I just went through the exact same thing, same readings as your getting. Drove me nuts for weeks. Can you make a separate line you can use to test the system. If you can make a 10 gauge wire with a 25 amp fuse and a momentary switch. Run it directly from your battery to the solenoid remove the yellow wire and see if it starts. That will confirm that your battery and your solenoid is good.

[dabald]

I wish I could say it did solve my problem, but it did not... I still can't get the starter to kick off!
I will make up a wire to run to the stater from the battery, with a fuse and a switch. I see your instructions suggest I should hook the temp wire to the yellow/stripe wire and then use the switch on the temp wire to kick the solenoid into action? I'm on it! Thanks for the idea!

[Cdnone1]

Disconnect the yellow wire that is attached to the solenoid from your ignition switch. Run the temporary fused and switched wire from your battery to the terminal on the starter solenoid. Push your momentary switch. If the solenoid engages and the starter spins then you know you have a good battery and a good solenoid and starter. If it doesn't start then you have a bad battery or starter solenoid and will have to have the battery and starter load tested. If it does start your battery and stater are good and your problem is else where and I can help you with it. If it doesn't start with your temp wire try connecting the temp wire to another known good battery. If it starts you have found your problem. The battery can show 12 volts but not be putting out enough amps to crank the starter.

[Cdnone1]

Do you ever eat at Firefly in Panama City?

[dabald]

Thanks for the details on the temp wiring! I'll be testing that theory tomorrow after work. Firefly is a real nice place!

[Cdnone1]

Good luck
Next time you go to Firefly please tell Dave Trepp Steve Vernon say's hi!

[T77911S]

just jumper the large battery wire on the starter over to the yellow wire to do a quick test. if that does not work, your start circuit may be good.
i have a push button switch with to clips on the ends of the wires that makes it easy for me to do this.

is there more than one terminal for the yellow wire? (yellow wire connected to wrong one?)