Start/starter/no start wiring quiz - Troubleshooting - VWDiesel.net The IDI, TDI, and mTDI source.

• Start/starter/no start wiring quiz by Kneale Brownson on 20 Jun, 2008 15:22
• Starter on my 1994 Jetta with the 1.9 TD (Canadian car) had so much corrosion on the braided ground wire for the brushes the wire crumbled, so I got a new starter from the local Bosch serviceman because that was less expensive than an overhaul.
  
  Got it installed, started the car, drove it out of the barn and to a parking spot in the yard, and when I went to start it a bit later, the idiot lights in the dash went out as I turned the key after the glow plug light went out and there was no starter activity.  
  
  Then there were several clicking noises from the fuse/relay area and the alarm horn started beeping.
  
  I recently replaced four dead glow plugs and Vincetized my glow plug circuit (see "how to pimp your glow plug wiring" at  http://vincewaldon.com/index.php?option=com_content&task=blogsection&id=4&Itemid=26), and it had been working fine before the starter wiring fell apart.  Best starts since I bought the car a year ago.
  
  When I put the new starter in place, I discovered it lacked the connector to accept the VW connector for the exciter wire, and instead had a spade stud, so I made a jumper out of 10 gauge wire with a spade on one end to go into wiring connector and a female on the other to slide over the spade on the starter.
  
  When the misbehavior started, I took apart and cleaned/dielectric greased the ground wire to the engine.  That didn't help any.
  
  Any clues to what to check next?
• #1 by burn_your_money on 20 Jun, 2008 16:34
• a dead or dying battery is my guess.
  
  Try hooking the exciter wire up to the battery (in nuetral of course) and see if it cranks over.
• #2 by Kneale Brownson on 20 Jun, 2008 16:53
• I'll give that a try, but the battery's been on a battery tender for a couple days while I worked on replacing the starter.  Prior to that it was on a battery tender for a week while I was fiddling with the driver door window winder, which wouldn't wind.  I ended up replacing the winder and it worked well.  Battery sat all winter and started the car when it got warm enough to start without the glow plugs working.
• #3 by burn_your_money on 20 Jun, 2008 17:36
• The starter might also not be grounded well enough
• #4 by Kneale Brownson on 20 Jun, 2008 18:41
• I had cleaned up the starter mounting spot and treated it with electronic cleaner before adding dielectric grease to the interface between starter and mounting.
  
  Trying Burn's suggestion, I got a snort out of the starter when jumpering the exciter wire post to the positive bettery post, but the damned alarm horn started blaring, and the next door neighbor's kids would be in bed now, so I had to break the connection before the starter had a chance to turn over.  
  
  The battery shows 12.5 volts too.
  
  However, I put the continuity meter on the ground connection to the engine and found that I got no resistance some times and a huge resistance otherwise, so I think I need to cut the end off that piece of cable and install a new lug on it.  Despite cleaning the faces of the lug, I see there is some green on the end of the wire.
• #5 by burn_your_money on 21 Jun, 2008 04:37
• Quote from: "Kneale Brownson"

  However, I put the continuity meter on the ground connection to the engine and found that I got no resistance some times and a huge resistance otherwise, so I think I need to cut the end off that piece of cable and install a new lug on it.  Despite cleaning the faces of the lug, I see there is some green on the end of the wire.

  
  
  The more correct way of checking to see if you have poor connections is to do a voltage drop test. Basically you would put one lead on the negative terminal, and one on the stater/bolt/engine/cable etc. Basically whatever section of the circuit you want to start. The other end doesn't have to be on the negative terminal either.
  Set your voltmeter to voltage. Crank the engine over. You need to load the circuit up. Whatever the voltmeter reads when cranking is the voltage drop. You want to keep that number minimized. I think 0.2V per connection is acceptable. If you are going across the starter you will see a large voltage drop because that's how many volts the starter is using
• #6 by Kneale Brownson on 21 Jun, 2008 05:14
• Shouldn't I be able to test continuity to ground--the theory is I've lost the ground connection to the engine--by connecting the ohm meter to the negative side of the battery and the engine almost anywhere?
• #7 by burn_your_money on 21 Jun, 2008 05:16
• yes and no. That will show if you have a connection or you don't. The method I posted shows how good that connection is.
  
  For example, if you have 1 single stand of wire connecting the battery to the started you will show no (or little) resistance but when you use the method I posted you will show a massive voltage drop because the wire is not capable of carrying the load.
• #8 by Kneale Brownson on 21 Jun, 2008 06:37
• How do I do your test when the issue is the electrics all go bonkers when I turn the key. Even before I reach the "start" portion of the ignition switch, all the idiot lights disappear, the mileage and clock dissapear, the alarm horn starts blaring, etc.  I also note that whenever I turn the key, the clock on the dash returns to 12:00.
• #9 by burn_your_money on 21 Jun, 2008 07:30
• you are correct, for a totally failed connection your method is better, I didn't realise that everything powered down, I thought that just the starter did nothing. You can use booster cables to bypass parts of the circuit to try and identify the bad section however in re-reding your post it sounds like you have found the culprit
• #10 by Kneale Brownson on 21 Jun, 2008 11:27
• Turned out to be the battery ground cable.  I cut a couple CMs of grungy green cable off the engine end of the cable, clamped on a new terminal and still had the same problem, so I investigated the battery end of the cable.  It was stiff and full of corrosion.  I cut it back about 5 cm and then had to cut another 2.5 cm to get to where the center of the cable wasn't full of the green crap:
  
  
  
  I also found the battery negative clamp is about toast too because the lead is falling apart.  Does a new OEM clamp come with a new cable?  Where would I find either the assembly or at least a new clamp so I can fabricate a new cable?
• #11 by burn_your_money on 21 Jun, 2008 12:15
• Depending on what connections yours has you can probably just get one from canadian tire. Fastenal also sells a kit for making your own
• #12 by Kneale Brownson on 21 Jun, 2008 14:07
• First trip with the reconnected diesel was to a local auto parts store to buy some cable and clamps to fabricate my own.  When I put the ETKA part number for that cable into a couple of dealer parts search features, I got back prices around $80.  Local pricing was around $20 but I loose the metric bolts.
• #13 by burn_your_money on 21 Jun, 2008 15:46
• Saving $60 for SAE sounds fair to me. Frucking dealer