Curious electrical problem from first-time poster - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Curious electrical problem from first-time poster by kitmburau on 22 May, 2016 11:40
• Hello All-
  First a bit about my truck.  It's an '81 Rabbit pickup (about 200k on body/guts) with an AAZ engine swapped in (about 30K miles ago with the previous owner).  Car also came with a transplanted steering column and rack/pinion from a Cabriolet (from a ? '88 or so Cabrio) because the previous owner wanted power steering.  First off thank you everyone for the mass of information that I've been reading as a bystander; it has helped with a great number of fixes thus far. 
  
  My current dilemma:
  An issue that has been occurring with increasing frequency for about two years which now is occurring during any drive longer than about 10 minute;  I will be driving down the road, and quite abruptly, my engine will shut off entirely as though someone just turned off the key.  The dash cluster goes out with it, the headlights go out with it and the horn stops noising (although when the steering wheel button is depressed you can hear the horn relay click).  The dome light and hazards continue to work. 
  
  Typically I coast in neutral to the side of the road and turn the key off.  For a short time (although the amount of time seems to be getting longer now) if I try to turn the key to the on position, no lights appear on the dash cluster, the engine doesn't turn at all; nothing.  It's as though the ignition switch has become non-functional (although again the headlights are gone and the only the horn RELAY fires; which makes me suspicious that it is not the ignition switch itself since these usually operate with the keys out of the car).  Then usually if I wait 5-10-20 minutes, if I try turning the key back on, everything in the dash cluster lights back up and it is business as usual.  When I turn the key to crank, the starter motor sounds nice and vigorous (not at all sluggish) and the engine starts right back up.  The horn and headlights come back and I drive on my merry way.  The engine starts nice and quickly every time so I assume it's not the battery or starter that is the problem.
  
  In an attempt to fix the above symptoms I have done the following:
  --Removed the aftermarket cruise control as it wasn't working anyway and I wanted to simplify wiring under the dash.
  --Changed my battery post connectors to marine-style ones.
  --Entirely replaced the main hot wire going to the starter motor from the battery.
  --Entirely replaced the main ground wire coming from the batter to the transmission mount. 
  --Added independent ground wires from the negative battery post to a valve cover bolt and to the alternator.
  --I replaced the voltage regulator on the alternator.
  --Tested all of the fuses (which seem to be fine)
  --Beaten my fists against a brick wall repeatedly.
  
  Despite the above, the symptoms continue.  As I am not the one who did the swap, I am somewhat ignorant to the details of how these AAZ engines usually get wired in.  Usually the problem is so transient that I don't even have time to get out my multimeter before the problems "fixes itself again".  Honestly though, even if the problem persisted I'm not sure I would know where to begin with the multimeter.  Any advice would be appreciated.  My hopes are that someone out there has had a similar problem and knows of a fix for it.  I've attached a picture just in case it demonstrates better than my words did, how I've tried to spruce up my ground contacts.  Thank you all. 
  
  Kit
  
  
• #1 by mtrans on 22 May, 2016 12:21
• Quote from: kitmburau on 22 May, 2016 11:40

  only the horn RELAY fires; which makes me suspicious that it is not the ignition switch
  
  
  

  for me it`s ignition switch/or/and mechanical kay which turn on ignition,just my 2c
  
• #2 by ORCoaster on 22 May, 2016 12:38
• Back in the day when I had trouble with my engine deciding when to turn off I found that under some conditions, bumpy roads, pothole, fast stop...
  
  The ignition wire was coming off the terminal of the key switch itself.  I would twist the steering wheel to and fro and that would connect it enough to get it running again.  Perhaps you just need to crimp it a bit and assure yourself it is on and staying on as you drive. 
  
  This problem sounds like a loose positive or negative wire to the ignition switch to me.  Aren't the lights, the headlights that is tied to having the ignition on.  Otherwise it is just the parking/running lights that come on. 
  
  
• #3 by RustyCaddy on 22 May, 2016 12:38
• Have you tried replacing the fuse box?  For me, on the old style (pre-1981) fuse box, it was the "X" circuit.
• #4 by kitmburau on 22 May, 2016 13:37
• I have not tried replacing the fuse panel.  From the quick read I just did, would I be able to simply buy a new "load reduction relay" and swap that out to see if my problem goes away or would I have to replace the entire fuse panel. 
  
  If it turns out to be the ignition switch, is the process similar to remove a (possibly ~1988) cabriolet ignition switch.  I know for the rabbit ignition switch removal my bentley manual calls for drilling a small hole in a very precise location in order to depress a locking pin that will then allow the switch to be pulled out.  Is it similar on a cabrio ignition switch?
  
  THANK YOU ALL FOR THE REPLIES!!!
  
  Kit
• #5 by vanbcguy on 22 May, 2016 21:20
• While the load reduction relay definitely can cause issues it doesn't cut off the ignition (it wouldn't do much good otherwise, no ignition when cranking the starter wouldn't work so well!)
  
  The ignition switch sounds like a reasonable place to start. The headlights on all the VW's I have owned switch off with the key off  (though the marker lights stay on). Remember there are multiple circuits going through the switch too - it can be just one set of contacts that has gone bad, or easily the wiring like ORCoaster suggested.
  
  Sent from my XT1097 using Tapatalk
  
  
• #6 by kitmburau on 23 May, 2016 07:59
• Okay so I replaced the load reduction relay yesterday (mostly because it was only $10 locally and the original metal housing of the relay was loose when I went to inspect it).  From the sound of it though; this likely will not solve my problems. 
  
  I also broke the (cabrio) steering column down far enough to unplug and then re-plug the harnesses that inserted into the ignition switch and then the ones under the column as well (horns/signals etc.)
  
  Looks like my next step will be to inspect the ground wire going to the entire fuse panel, and then I guess I will replace the ignition switch since the wiring harness going to it looked to be in good order. 
  
  I'll post again if/when I've fixed the issue so that others can benefit from this string. 
  
  Thanks for the advice everyone!  Keep it coming if anyone else has some tips.  Cheers.
  
  Kit
• #7 by kitmburau on 09 Jun, 2016 05:58
• So for the sake of completion I figured I would post an update on how my problem finally seems to have been fixed. 
  
  Ultimately it seems that it was one of the two main ground wires coming off of the fuse panel and screwing into the firewall.  It seems most likely that it was due to corrosion on either the screw or wire lead or both where they were threaded into the firewall.  After the other things I tried (which I will list below) that still didn't fix the problem, when I cleaned up the ground connections TAH-DAHHH , it stopped dying on me while driving.  It has been running without fail for about 2 weeks now, which is a huge improvement already
  
  Other things I tried in addition to the stuff I listed above in the earlier posts.
  --I checked all the fuses
  --I replaced the x-relay (load reduction relay)...still no better
  --I replaced the ignition switch...still no better
  --I bought a common ground connector (usually used for installing speaker systems in cars) and cleaned up all the small ground wire connections behind the fuse panel where they all flow into the two main wires that bolt to the firewall.  Still didn't work
  --Ultimately the connection from the ground to the frame was the failure site.
  
  Hope that someone out there can learn from my frustrating experience.  My bottom line turned out to be ....
  
  DONT TRUST THAT THE FUSE PANEL GROUND WIRES ARE SOLIDLY CONNECTED TO THE FRAME OF THE CARE UNTIL YOU CLEAN THEM UP WITH SAND PAPER AND SMEAR SOME DI-ELECTRIC ON THERE TO FORM A GOOD GROUND
  
  It worked for me.
  
  Thank you all for helping me with this!!!!
  
  Kit