Damn Alternator Gremlins!

[rennch]

Yesterday myself and fellow Listeroo Pat Snyder worked on my 72, adjusting the CIS. After getting the motor humming along splendidly, we focused our efforts on my weird/faulty 14 pin plug that, when jiggled, would shut the car down in an instant. 5 minutes and some diaelectric grease later, all was well in the world.

On the way home, I was *shocked* that my lights and instruments were SO MUCH brighter than they had been. "Man, that dialelectric grease is good stuff!", I thought. I was thinking I was going to have to replace my alternator, b/c my battery went dead all the time. So, I'm tooling down the highway on my way home and THUMP!...I hit a bump in the road. Normally, no big deal, right? Well, this time all my lights and instruments went dim again. THUMP!!! Another bump...there they were bright and shiny again! So, I went the whole way home like this...fortunately, the THUMP's in my favor outweighed the THUMPS NOT in my favor. So, I made it home without the car shutting down due to lack of battery power.

So, the question remains...where do I *start* to troubleshoot this irksome connection? I have pulled the alternator in the past, and all looks well down there. All the wires are connected, and seemingly ok. Do I Dialectric Grease the contact points on the alternator? ON the starter?

Any electrical gurus out there?

Thanks,

mto

[rennch]

Oh, before I forget. I must comment on how awesome Pat's setup in his garage is. Clean, super organized, and ready to rock. The fridge full of beverages and the the TV on the wall-swivel are rockin'. And Pat, far more right-brained than I am, is leaps and bounds ahead of me at this point with these cars, even though he bought his only a month before I bought mine. Thanks Pat, for all the help.

[scottb]

I'm not an electrical guru, by any stretch of the imagination, but in reading this board over the past couple of years, it seems that the people who *are* electrical gurus always suggest starting with the various grounds on the car. So, that might be a place to start.

My $.02.

[TerryBPP]

First, check to see if your battery terminals are connected well. Second, check your ground from the alternator to the motor (you will have to remove the fan). Third, consult John Kramer. He is a master of the alternator arts.

[Lorenfb]

With those old cars, you need to clean and solder all the key connections
at the crimped connector lugs.

[echrisconnor]

I agree with checking your other grounds. If you pull the alternator bring it down to Vanatta on 8th & Pearl. They just rebuilt my alternator and have been great at testing and troubleshooting a couple others I've had in the past.

[rennch]

Hi Chris,

Good to see another Boulderite on the list. I actually have another alternator at Vanatta at the moment.

You missed our PCA lunch today at Conor O'Neills.

[echrisconnor]

Crap! I would have loved to have been there... I'm an RMR member but didn't see that on the event list. Is there a large local following. I only know a few through some of the DE events over the past couple years.

[rennch]

Are you on the Yahoo Groups list? Thats where you need to sign up.

[echrisconnor]

e-mailing you @ your ...whirledmedia address

[john walker's workshop]

is the trans to body ground strap there? clean and tight? the fuse terminals on those older cars get pretty crusty. check all the upper ones with red wires for clean and tight.

[rennch]

I haven't checked on the ground strap...where is it located? I've got the 915 tranny...where should I look for it to be attached?

Also, does it make any sense to use some diaelectric grease on the fuses themselves?

I've already cleaned the heck out of the fuse block, front and rear.

[vash]

i think there is a picture of the ground strap in wayne's 101 book. i see it right at the tranny mount on my car. it is pretty obvious. a big, greasy, nasty, braided copper, flat wire.

[304065]

The grease is cool, it will keep out moisture and block corrision. But that's the last step after you have already cleaned and tightened the connections.

So you hit a bump and the lights went dim. They didn't flicker and the car didn't die, they just dimmed. That suggests a high-resistance connection somewhere.

So how does power get from the alternator to the fuse box? There are two paths it can take. One is through the engine wire harness-- there are a couple of fat red wires and a brown ground wire in there.

The other path is through the heavy-gauge wire that runs from the alternator B+ terminal through that rubber grommet at the forward edge of the engine tin and to the lug terminal on the starter. Then it goes forward through the battery cable in the tunnel to the battery + terminal.

So that's six connections on the engine harness, one on the alternator, one on the starter and one on the battery. Also, hidden under the electrical console there's another 14-pin connector, you will want to make sure that's tight also. Then you have the fat red wires that come off the battery and go to the fuse panel, so there's a couple more.

Finally as JW says you have the engine ground. I'd start with that, it's under the car and exposed, it oxidizes, and every time the engine/trans bounces around it flexes. Disconnect both batteries first, you don't want to weld yourself to the car while you're checking this stuff, and make sure you have some good jack stands to support the car with, you don't want to get squashed like a cartoon coyote. While you're under there checking the ground strap, check the connection on the starter, make sure its clean and tight. If you pull off the yellow wire to the starter solenoid, make sure you put it back on or the car won't start. There's going to be tons of grease around those starter terminals I bet. Next, I'd check the console. Make sure it's tightly fixed to the body and there are a couple of ground wires that sandwich between it and the body that need to be clean and tight. Check that hidden 14 pin connector underneath, also. Finally, make sure your batteries are tightly clamped down and check the battery positive and ground connections against the body.

That should take the better part of a day to check and tighten everything. Some guys use electrical contact cleaner, some use denatured alcohol. I use contact cleaner from radio shack and a scotch-brite pad to really get things bright.

Good luck!

[rennch]

John,

You rock. Thanks for all the great advice!

[Pat S]

Good write-up John.

Thanks for the kind comments above emptyo... I think.

I still haven't figure out if

far more right-brained

really translates to "rediculously anal rententive" or not, but hey even if it does, it's probably true

Pat

[rennch]

Ok...I *finally* have some time, and weather cooperation to work on the alternator issue today. So...I'll keep Y'all posted.

[Pat S]

Yeah! Good luck.

[rennch]

Thanks Pat. Wanna come down and help?

[Early_S_Man]

mto,

As John said, the cleaning has to come before the silicone grease!

The 14-pin connector has particularly delicate silver-plated brass pins and sockets that you don't want to use anything more abrasive than a pink pencil eraser on ... chemical silver cleaner and pipe cleaners would be one way to clean them, but any way is going to be tedious! I recommend unbolting and removing the entire relay/fuse/CDI panel to have better access to the 14-pin connectors without placing undue stress on them.

After the 14 pins on the male side are clean ... I suggest spreading the pins VERY SLIGHTLY with the blade of an Exacto No. 11 knife.

The 14-pin connectors are very critical to the alternator, since the Blue #61 wire passes thru them! Any corrosion on the silver pins raises the resistance in the field pre-energize circuit to the warning lamp, which can raise the Zero-Ampere rpm level, and cause a glowing warning lamp at night!