A few weeks ago my battery seemed be going dead so I'd put it on the charger over night. But it didn't seem to help... one morning I turned the key, motor barely turned over... I held the key in the start position to try and get the motor started... probably about 30 seconds or so. About that time, smoke started bellowing up from under the dash. So I turned the key off, the smoke did not stop bellowing. I then, as quick as I could, disconnected the battery. Smoke stopped. Not exactly sure what caused the issue but the wires that went from the fuse panel to the stereo were fired and also damaged the GND wire I had going from the stereo back to the battery. I took out the bad GND wire and totally disconnected the stereo. Now the car won't turn over at all (with a brand new battery). When I turn the key, I hear a click, which is the starter trying to turn but then everything goes dead immediately after. I obviously have a short somewhere else but I was wondering if someone could check something for me... I am measuring a little more than 3A when the key is in the ON position (not the start position...). Measured by disconnecting one terminal from the battery and connecting an ammeter in series. Can someone please tell me what they are seeing for current?
Thanks,
Rob
Full Version: Electrical Gremlins
Rob,
I could do that, but I don't think it would help you any. When the wiring smoked, it probably caused some more damage in the key switch and/or wiring harness/fuse panel.
I don't think 3amps is too high of a current draw with the key in the on position. Every car would likely be a little different.
I would really suspect the key switch and wiring. Another guy had a similar problem this summer and he found wires bad from the engine bay to the dash. Before you have some more smoke, I would do some in depth checking of the wiring harness and fuse panel including the key switch, and complete starter circuit. Keep at it and let us know what you find. We will help you get thru this.
Because you were having the battery going low on you before all this smoked, I would look closely at the positive wire from the alt that is connected to the starter. If you have a connection going bad there, it can cause problems similar. Also tranny ground strap - clean and tight.
When you are looking at connections be sure to look where the wire is crimped inside the connector. If there is corrosion in there, that is not good! October Excellence had a good write up on electrical connections and how to fix them.
Tom
I could do that, but I don't think it would help you any. When the wiring smoked, it probably caused some more damage in the key switch and/or wiring harness/fuse panel.
I don't think 3amps is too high of a current draw with the key in the on position. Every car would likely be a little different.
I would really suspect the key switch and wiring. Another guy had a similar problem this summer and he found wires bad from the engine bay to the dash. Before you have some more smoke, I would do some in depth checking of the wiring harness and fuse panel including the key switch, and complete starter circuit. Keep at it and let us know what you find. We will help you get thru this.
Because you were having the battery going low on you before all this smoked, I would look closely at the positive wire from the alt that is connected to the starter. If you have a connection going bad there, it can cause problems similar. Also tranny ground strap - clean and tight.
When you are looking at connections be sure to look where the wire is crimped inside the connector. If there is corrosion in there, that is not good! October Excellence had a good write up on electrical connections and how to fix them.
Tom
I had about the same thing happen to my 68 mustang once, it started with a broken wire and resulted in melting the harness in the dash. I tried to fix it but after a week of trouble shooting i decided to just bite the bullet and upgrade to a painless system. The harness on the 914 is pretty simple and you can get away with one of the generic harnesses. I've found with any old car the wires just seem to fall apart and can short out. Its never a bad practice to spend a couple hundred bucks and save yourself from a car fire.
This is way beyond Gremlins!
If it were my car...
I would take out the entire harness (not that hard, just label everything) and check every wire one by one and fix them. Copper has a tendancy to conduct heat very well. Even though you saw smoke at the dash, you may have melted insulation throughout the harness now. A dead short will make the wire react like a heating element. It will turn red hot and melt the insulation. t the same time, replace the ignition switch. Clean the corrosion from all the ground connections. reinstall and drive.
If it were my car...
I would take out the entire harness (not that hard, just label everything) and check every wire one by one and fix them. Copper has a tendancy to conduct heat very well. Even though you saw smoke at the dash, you may have melted insulation throughout the harness now. A dead short will make the wire react like a heating element. It will turn red hot and melt the insulation. t the same time, replace the ignition switch. Clean the corrosion from all the ground connections. reinstall and drive.
I was able to troubleshoot this a bit last night and I haven't been able to pin point the problem yet... but I am getting closer, I think. I started on a similar path as Dan did in his thread, 'Parasitic battery drain'... as this problem is starting to be very similar.
To make a long story short, I think I narrowed the problem down to something in the starter circuit. I was able to verify the electrical connections up to the relay board are OK. There are two big connectors on the relay board. The one towards the front (of the car) contains a big yellow wire which comes from the ignition switch. So, everything up to that point checks out OK.
With the connector towards the rear disconnected, I was able to verify that I get 12V on pin 6 when the key is in the start position. So, that checks out OK too.
Here's the weird part... with the key in the on position, I apply 12V directly to pin 6 on the rear connector (which should turn the motor over) I just hear the starter solenoid click and my gauges go dead. Turn the key off and then back on... gauges come back on.
The next thing I tried was I disconnected everything from the battery and tried the same thing to just get the starter to turn the motor over. Click... then I hear the fuel pump turn on... That's weird... I thought I had everything else disconnected. That's when I went to bed.
To make a long story short, I think I narrowed the problem down to something in the starter circuit. I was able to verify the electrical connections up to the relay board are OK. There are two big connectors on the relay board. The one towards the front (of the car) contains a big yellow wire which comes from the ignition switch. So, everything up to that point checks out OK.
With the connector towards the rear disconnected, I was able to verify that I get 12V on pin 6 when the key is in the start position. So, that checks out OK too.
Here's the weird part... with the key in the on position, I apply 12V directly to pin 6 on the rear connector (which should turn the motor over) I just hear the starter solenoid click and my gauges go dead. Turn the key off and then back on... gauges come back on.
The next thing I tried was I disconnected everything from the battery and tried the same thing to just get the starter to turn the motor over. Click... then I hear the fuel pump turn on... That's weird... I thought I had everything else disconnected. That's when I went to bed.
Rtalich,
Do your starter test again by applying 12 v to pin 6 rear connector, but first put a voltmeter across the battery cable terminal at the starter to ground and observe the voltage reading. Put 12 v to pin 6 and notice the voltage reading. If it is really low or 0v, you have a terminal connection breaking down under load. Later 911's have this problem a lot according to Excellence mag article. I recently was checking my positive battery cable terminal and took it apart and was surprised how corroded it was inside, none outside.
One other thing, is your battery cable getting warm? If so, you could have a shorted starter.
Tom
Do your starter test again by applying 12 v to pin 6 rear connector, but first put a voltmeter across the battery cable terminal at the starter to ground and observe the voltage reading. Put 12 v to pin 6 and notice the voltage reading. If it is really low or 0v, you have a terminal connection breaking down under load. Later 911's have this problem a lot according to Excellence mag article. I recently was checking my positive battery cable terminal and took it apart and was surprised how corroded it was inside, none outside.
One other thing, is your battery cable getting warm? If so, you could have a shorted starter.
Tom
QUOTE(Tom @ Sep 24 2010, 10:26 AM) 
Rtalich,
Do your starter test again by applying 12 v to pin 6 rear connector, but first put a voltmeter across the battery cable terminal at the starter to ground and observe the voltage reading. Put 12 v to pin 6 and notice the voltage reading. If it is really low or 0v, you have a terminal connection breaking down under load. Later 911's have this problem a lot according to Excellence mag article. I recently was checking my positive battery cable terminal and took it apart and was surprised how corroded it was inside, none outside.
One other thing, is your battery cable getting warm? If so, you could have a shorted starter.
Tom
OK, will do that test and post what I find. Just an FYI - The battery cables are new (just a couple years old) and the starter is just a couple years old as well. Its the high torque starter. But just because its new(er) doesn't mean its not broke.
Thanks,
Rob
Well, I thought I found the problem over the weekend. A while back while troubleshooting a possible voltage spike issue, I installed a varistor. Had it connected on the starter to GND. I took it out and tried the pin 6 trick again... engine turned over!! So, thinking that, that was the problem, I put it all back together and ran some errands. Ran perfect.
This morning, I get in to go to work... click. Same problem. I was able to wiggle some wires and sort of narrow down where to look for the short tonight after work.
This morning, I get in to go to work... click. Same problem. I was able to wiggle some wires and sort of narrow down where to look for the short tonight after work.
From the sounds of your problem, check the ground strap connection from the trans to the body.
QUOTE(904svo @ Sep 27 2010, 12:22 PM)
From the sounds of your problem, check the ground strap connection from the trans to the body.
Took 4 days to get to this, and it's probably the right answer. Sorry folks, I would have jumped in on this one earlier, but I've been gone about 18 hours a day for the past week and didn't have any awake time at home. Remove the ground strap, clean it and its mounting points, inspect it, and reinstall it with nice (large) washers and good hardware.
The Cap'n
Actually Cap'n, it was in post #2!
Tom
Tom
Found the problem... smoking gun (pun intended). I did check the ground strap, the one that's above the tranny. That was one of the first things I did check... but, I hadn't checked the one that goes from the battery to the chassis. Needless to say, it was pretty loose!!
Because it was loose it caused the 12AWG wire I had going from the battery GND to the stereo chassis to carry all the load (at times) while starting the car. During that one time when the smoke occured, it was carrying all the load for the full time I was trying to get the car started, with a weak battery. And because that 12AWG wire was in contact with the hot wire going to the stereo, it melted the insulation off of both wires which caused the smoke. And because the GND from the battery was not making good contact to chassis, it wasn't getting a good charge when the car was running, which is why my battery was slowly dying.
Whew... it all makes sense now. Thanks for the help everyone!!
-Rob
Because it was loose it caused the 12AWG wire I had going from the battery GND to the stereo chassis to carry all the load (at times) while starting the car. During that one time when the smoke occured, it was carrying all the load for the full time I was trying to get the car started, with a weak battery. And because that 12AWG wire was in contact with the hot wire going to the stereo, it melted the insulation off of both wires which caused the smoke. And because the GND from the battery was not making good contact to chassis, it wasn't getting a good charge when the car was running, which is why my battery was slowly dying.
Whew... it all makes sense now. Thanks for the help everyone!!
-Rob
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.