Hi,
Well it seems that I have gotten myself into quite a situation over a project that I thought would take only an hour or so... I recently Purchased a new Starter Motor and Solenoid for My 1978 Vette. The old one was shot... I disconnected the Negative battery Cable, Disconnected the 4 Wires attached to the existing Starter Motor which consisted of (Large Red Wire attached to Center Large Post of the Solenoid, a small Red wire attached to the "S" post of the Solenoid, a Small Black wire attached to the Large Outside Starter Motor Bolt, and finally the Very Large BLACK Wire attached to the Large Inside Starter Motor Bolt). Everything Connected without issue and the starter motor aligned nicely. I went to attach the Negative Battery Cable and I never saw such sparks coming off of a battery. I actually got very worried at that instant... it was a very large arc and the wire got very hot. It was only on for a second or two and i removed it immediately. I guess i should consider myself fortunate that i was not hurt. I was absolutely positive that i connected things correctly but know something must be wrong because that behavior with the battery was not at all normal. I am not sure where to start to try and correct this as I can find no diagrams or Photos on this anywhere. And further - I am not sure if i just caused damage to something else in my electrical system when the arc occurred. Any Suggestions on what my problem might be and what other problems i may have caused and should check out? Sheez - I really didn't expect to have such issues with this simple project. Thanks in advance ~ Joe

 

I remember having a problem when reinstalling my starter not remembering which wire went where. I'm not at home, so can't help you, but wanted to suggest next time take a picture first, or at the least make a diagram. Something definitely doesn't sound hooked up right.

 

Well, I'm far from an electrical guru, but with the arcing and sparking, I can't help but think that you have a short. If everything was working fine and you changed your starter motor and solenoid and then the problem occurred, I would be willing to bet a case of beer that the problem is EITHER a short in the solenoid/starter motor, or you didn't get your connections right when you put the new motor in. The good news is that you probably didn't damage anything in your electrical system, your battery might not be real happy about what you did, but the electrical system of the car was almost certainly uninvolved.

What I would do: I would test for continuity between the thick black wire going to your starter and the frame. My guess is that this will show low resistance, confirming that you have a short. The thick black wire comes directly from your battery's positive terminal and provides the cranking amps to start the car, if this is shorted to the frame, I would expect to get what you experienced when re-connecting the battery. Assuming that is short, you need to figure out why. I would confirm that all of your connections are correct first because the next thing is a little less likely than connecting a wire to the wrong post. If you are sure all of your wires are connected properly, you can have a short inside your starter motor, especially a cheap remanufactured one that you are likely to get at the local auto parts store. To test this, check continuity between the hot connection (where the fat black wire goes) and the nose where it bolts to the block. If this shows low resistance, you have a bad starter/solenoid.

This should be an easy one.

PK

 

A couple thoughts: It sounds like your main power wire (red, center post on solenoid) is making ground somewhere, often happens where it bends and heads for the transmission tunnel, I'm having that issue on my '74 right now...

Also, there is usually another wire to the center post, could be a variety of colors, to feed the fuse box. Also, the fan motor wire is often a culprit...I think it is a black wire that looks like a ground wire but is actually a power wire...or vice versa. It is in that area and almost caught my '69 engine on fire.

Check the red cable first, to make sure it is not shorting to any metal.

Steve

 

Your 'BIG' black wire is the positive battery cable coming from your battery and needs to be on the large battery terminal on the starter solenoid along with the red wire that you already have there. The small black wire is the ground which you had hooked correctly under a starter bolt (mine is under one of the bell housing bolts). The small brown wire you have hooked up correctly as well to the small terminal on the solenoid. You are lucky that you got that big cable disconnected when you did or you could have had a real fire going You had the worst kind of short you could have, the ones that will blow tops off of batteries :-(

 

Hope this helps.

 

First of all - Thanks for the terrific feedback. I could use a case of beer right about now PK

I usually do take photos of complicated projects and document very well.. but i guess i just got in a hurry and didn't think it was necessary on this simple project. I was sure wrong about that and will always take my digital camera out to my garage with me from Now on!

I believe my problem may be in Steve's reply. That Large BLACK Cable - if that is in fact my Power cable (boy i feel like an idiot) and I have it attached to one of the two Main Starter Motor Retention Bolts - this would certainly do it. I could have sworn that is where i removed it from and it was a ground. Ok then - so apparently this is not my Ground and it attaches to the Solenoid. I am assuming to the Center Large Post of the Solenoid along with the other Red Wire. (i also have one small red wire going to the S post of the solenoid) That would mean that i only have one small ground wire going to the starter motor chassis bolt. Does this sound correct? If anyone has a photo of their starter and cable connections i could sure use one right about now.

 

Yes - just as i completed my reply to halfmoontrail and PK - I saw yours. And yes - that was very bad. Thanks very much for confirming my suspicions! and thanks to you as well Bob for the Diagram!

I'll let you all know how it turns out

 

I certianly did not suggest that a large black cable should be hooked directly to the starter solenoid...typically the main power from the battery is RED, and is obvious.

 

Not on my '70, the fat wire carrying the big amps is black, and labeled black on the wiring diagram so I don't think Bubba changed its color. The relatively heavy red wire carries the current to the harness, the purple wire is the ignition switch wire and the yellow wire goes to the hot side of the coil. There is also a thin black wire that is a ground from the blower motor that shares a connection with the black grounding strap that goes to the frame. On my car, you wouldn't confuse the relatively thick grounding strap with the thicker power wire (even though they are both black) because it is visually obvious that it is a grounding strap since it is bolted to the frame a few inches from the starter. His car is a '78 so there are some differences in wire colors, and I think his car doesn't have the equivalent of my yellow wire since he probably has electronic ignition and I have points.

 

Sorry if it was already mentioned but you've probably trashed your battery. I hooked the starter in my 79 back up correctly but the hot lead was contacting metal somewhere and caused the exact same arcing nasty pop. I didn't want to get near the batery for a month. Once I got it sorted out I found the battery was toast. Just an FYI.

Be careful...big amps from a battery can take you down.

 

WELL - first of all i am new to the Forum but i love it and i will frequent it often! It is nice to share my passion with others who have it as well

The Big Black wire was the Positive from the battery and as soon as I moved it to the Center Post of the Solenoid - and "CAREFULLY" reconnected my battery cables - She cranked right up the very first time. Battery seems ok, all electronics seem ok, and volt-meter is showing very healthy charge!

Thanks very much to all of you who provided feedback! It was just a stupid mistake that i made but i learned a tremendous amount from it as well as finding some new friends!.... Thanks again and see you soon!

 

Joe, glad things worked out. All of us at one time or another have had some 'not so bright' moments Welcome to the forum!

 

Joe,
The ground from the battery does not go to the starter, but to the chassis right near the battery. Just forward of the starter motor is a heavy ground strap from a bolt on the engine mount bracket to a bolt on the engine block, where the starter motor forward support strap bolts.

Others are right when they say that the starter motor positive lead is black, it's the only +ve lead in the car that is !!, so I can understand how you could mistake it for a ground. Thanks for sharing as I'm sure that more people than you have learned from this. We all make mistakes.

Regards from Down Under

aussiejohn
4 months to go

 

Only on Fords and Chryslers, GM cars are black as a OE product. As cars get older and less useful, subsequent owners are sometimes very price conscious and purchase discount store products that sell 'red' cables for both the hot and negative causing a different but similar situation. 'crossed battery cables'...just a different color.....

Vettes, 'both' are black