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Pacmanfever
Samba Member
Joined: January 29, 2013
Posts: 201
Location: Kansas
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 Posted: Thu Jun 11, 2015 1:31 pm Post subject: Stumped by a smokey wire |
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My son's 67 always starts right up and has been extremely reliable, a couple weeks ago I started it to warm it up, it ran about a minute and died, which it has never done before. It would crank over fine, but not restart so we went for the basics- spark, fuel, etc. Not getting a spark, we replaced the points and condenser, and coil for good measure.
It started right up! But after running for a couple of minutes we began to see smoke coming from near the steering column. We shut it down and disconnected the battery cable. The smokey offending heavy wire appears to be coming from the ignition switch area and it's getting overheated, but no fuses have blown.
Any ideas as to why this wire would start overheating suddenly? Resistance in the ignition switch maybe? Stuck relay? Aliens? I don't see any smoking gun like a chaffed or burnt wire grounding out so far. |
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slow36hp
scott wimberley
Joined: August 09, 2004
Posts: 3113
Location: mukilteo washington
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xcoldgrimjimx
Samba Member
Joined: November 18, 2011
Posts: 254
Location: CA
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| Posted: Thu Jun 11, 2015 3:00 pm Post subject: |
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Hello dude or dudette it sounds like the ignition is sticking in the (fire up) position. When you go to start it the spring back is not working properly in a sense STAYING HOT so try dissembling the ignition.. or a simple way is to keep ALL POWER OF YOUR BUS! BATTERY DISCONNECTED ! and simply turn the key. If it just doesn't feel right ( springing back like it should normally) on its own. Than you have your problem. It doesn't hurt to trace this from the start and go back (can't go Wong that way  ) let us know 
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ya it's rusty...but it's MINE!!!!! |
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telford dorr
Samba Member
Joined: March 11, 2009
Posts: 3625
Location: San Diego (Encinitas)
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| Posted: Thu Jun 11, 2015 3:53 pm Post subject: |
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Note that power flows from the ignition switch (D) via the black wire to the top of the 7th fuse, then continues to the engine coil. After that, it goes to the choke heater and the idle solenoid on the carb.
ALL of these wires (for some inane reason only VW knows) are UNFUSED.
Thus, if there's a short anywhere in this circuit, you'll get smoke.
Check all black wire connections and devices for shorts or other issues.
I built and use this as a big test light:
Disconnect the battery '+' terminal, and connect the big test lamp between the battery '+' post and the disconnected wire. If there's a short in the ignition circuit, with the key on the lamp will light. To find the short, wiggle / disconnect wires until the lamp dims or goes out.
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'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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Pacmanfever
Samba Member
Joined: January 29, 2013
Posts: 201
Location: Kansas
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| Posted: Thu Jun 11, 2015 6:53 pm Post subject: |
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You guys are amazing, thanks for all the detailed info. I'll tackle this issue in the morning, we've got thunderstorms rolling in right now.
I'll be sure to post a follow up. |
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Ran When Parked
Samba Member
Joined: September 26, 2013
Posts: 781
Location: Birmingham, AL
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| Posted: Thu Jun 11, 2015 7:38 pm Post subject: |
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| Pacmanfever wrote: |
| You guys are amazing, ... |
So true. |
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jason
Samba Member
Joined: August 07, 2002
Posts: 3462
Location: Garage
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| Posted: Thu Jun 11, 2015 9:57 pm Post subject: |
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| I say resistance. I'm always tracing wires at work that are melted because of a loose wire nut. If it was stuck on you'd hear the starter. Unless he means slightly open and there is a bunch of resistance in the ignition. Just measure across the terminals with an ohmmeter. |
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Pacmanfever
Samba Member
Joined: January 29, 2013
Posts: 201
Location: Kansas
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| Posted: Fri Jun 12, 2015 9:07 am Post subject: |
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Here's a quick update: I checked the ignition switch and it springs back properly from the start position to the run position. It does feel a little loose between the off and run positions, but I don't have anything to compare it to.
So I moved the speedometer out of the way to get a good look at the wiring that was overheating, and discovered one terminal of the ignition switch is blackened, which I'm going to guess is the source of our car-be-que.
The tape was left on there as an identifier when I removed the speedometer to freshen it up, it's not serving duty as in insulator.
So now the question is it internal resistance in the ignition switch? Loose terminal rivet? Or overloading on that line that's causing failure at the point of greatest resistance?
Here is the backside of the switch and the offending terminal:
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slow36hp
scott wimberley
Joined: August 09, 2004
Posts: 3113
Location: mukilteo washington
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