[Vwdiesel] no start, relay and a smoke puff

[Chris Jude]

Yes, it does seem to always crank fine with the GP relay out.  It also very
often cranks normally with it in!
I really don't want to drive this car at all until I can track and correct
the problem, but i still have to get to work everyday so I need a good
weekend of ground chasing.  I'm a little shaky on testing circuits, but I
just need to get my electrical tester and test either for continuity or
voltage I guess.
I cut the burnt wire out and taped up it's ends, which I know is not the
right fix, but I wanted to get the bare wire out of the wire bundles for
the immediate future.   I've already bought a 2000 Jetta TDI, but I'm
waiting for the seller, a friend, to finish a manual tranny swap before I
take ownership.  I just need the 85 to make it another week or two before I
can pull her off duty and really go over the car correctly.

chris

On Thu, Mar 15, 2012 at 2:08 AM, James Hansen <jhsg at sasktel.net> wrote:

> Comments below...
>
> Okay, so if the car doesn't crank at all... lets assume it's because the
> starter solenoid isn't getting enough voltage to switch.  You pull the GP
> relay, and now it does get enough.
>
> And it always cranks normally with the GP relay out?
>
> And the dead battery...
>
> I wonder if the GP relay is sticking "on" sometimes, pulling enough power
> to
> prevent the starter solenoid from switching on?
> ___________
>
> But this still points to a bad fuse panel or connections at the back.  Low
> voltage in gives low voltage out. The 85 has the crappy high oxidation
> factor plug in jacks on the back of the panel from each harness bundle.
> Don't screw with anything until you have disconnected the battery, removed
> the one screw holding in the fuse panel, pulled the panel and the mess of
> wires away from the firewall, and had a good look at the back, and where
> all
> the wire bundles plug into the back of the panel.  Pull each plug out of
> the
> socket, and examine, clean if necessary with a good electrical contact
> cleaner, and replace the plug. This is a known problem area, and is a
> source
> of many burned cars.  The puff of smoke would have me wierded out after the
> first occurrence.  Usually you let the smoke out of something, it does one
> of two things- next time refuses to function, or lets out HUGE volumes of
> smoke. Were I a betting man, I'd have 5 bucks on there being at least one
> partially melted harness to fuse panel connection plug on the back of the
> fuse panel. I'd suggest caution on using this car at all until you get it
> sorted out.  I've had an electrical fire in a tractor, no fun at all. Cab
> goes from clean air, to I can't see a thing nor breathe in under 2 seconds-
> 3 feet of vinyl wire turned red and cooked when it shorted out was all. No
> fun.
> ___________________
>
> Reminds me of my sister's old 68 fastback.  Started fine most of the time,
> but once in a while (usually after a long drive, like stopping for gas on a
> road trip) it just wouldn't crank.  Unfortunately an automatic, so no
> push-starting.
> _____________
>
> I still have my 68 fastback.  The ford starter solenoid was the fix for
> this
> at the time- just a relay at the starter to get a full 12v to the starter
> to
> pull the solenoid in. The wire from the battery, to the dash, through the
> poor-ish fuse panel, the fair contacts in the ignition switch, and back to
> the starter developed enough resistance in total, and only gave low current
> to the solenoid. Still tested as 12.4 v with a meter under no load which is
> what threw everyone, but was 9v with small load. Cold solenoid pulls in
> easier than a hot one too, which makes it tougher to diagnose.  I had a 68
> notch with this gremlin that kept coming back to the shop until I tested
> voltage at the starter under load.
> ----
> -James
>
> Sometimes a jump-start would do the trick, but waiting long enough (usually
> hours) always would.
>
> She had it in several mechanics/VW dealers between Oregon and Georgia, and
> they did lots of parts-changing, but nobody ever fixed it.  She eventually
> unloaded it on some poor sucker college kid from OSU (the car was OSU
> Beaver
> Orange).
>
> On Wed, Mar 14, 2012 at 5:48 PM, Chris Jude <vegbenz300 at gmail.com> wrote:
> > Yeah, it either doesn't crank at all, or it cranks just fine.  I
> > believe that there is a ground strap from the trans to the the chassis
> > that the battery is grounded to as well.
> > I've read and reread the legend for the Bentley manual wiring
> > diagrams, and it says the number listed with the wire color code is
> > the AWG.  Doesn't seem right though, as many of the wires are list as
> > .5 or 15.  For instance the code for the glow plug wire is 6.0 R/W I
> > must be reading it incorrectly.
> >
> > Chris
> >
> > ps- has the list been really really quiet, or is this the only active
> > thread right now?
> >
> >
> > On Wed, Mar 14, 2012 at 8:23 PM, Tad <tadc at europa.com> wrote:
> >>
> >> so when it doesn't start, does it crank normally?
> >>
> >> The starter grounds to the transmission body, and the battery
> >> connects to the chassis via the ground cable, but what about the
> >> connection between trans and chassis or battery?
> >>
> >> The oil pressure sensor sounds like a bad ground problem too, but I
> >> wouldn't swear they are related.
> >>
> >> I'm not too up on IDI diesels but I'm guessing the wire from starter
> >> to GP relay would be there to turn off the GPs while cranking?  But
> >> 4awg is way too big a wire.  Did you mean 14?
> >>
> >> Erik's got a good point too.  On my old 78 I had a whole list of
> >> bizarre intermittent problems that were eventually traced to a
> >> cracked backplane on the fusebox.
> >>
> >> One way to test my theory would be to put a voltmeter between the
> >> starter ground (trans body) and battery negative terminal.  It should
> >> read very close to zero(of course).  Repeat the test while cranking
> >> the engine - it should still read very close to zero.  If it doesn't,
> >> that means you've got a bad ground connection between the trans and
> >> the battery - in other words resistance between the two, causing a
> >> measurable difference in electrical potential when under load.
> >>
> >> Of course I couldn't actually tell you what good or bad numbers would
> >> be... :)
> >>
> >> On Wed, Mar 14, 2012 at 3:55 PM, Chris Jude <vegbenz300 at gmail.com>
> wrote:
> >> > Tad,
> >> >
> >> > Thanks for the reply.  I'm looking at the wire-diagram (admittedly,
> >> > I'm a little weak at electric diagram and DC troubleshooting),  it
> >> > looks like the starter grounds through the transmission body, and
> >> > the battery grounds at the ground cable, which looks ok  to me.
> >> > There is a 4awg wire goes from the starter to a pin on the glow
> >> > plug relay.
> >> > I've long had a funny problem on this car where the oil pressure
> >> > buzzer goes off randomly, and is often (not always) shut off by
> >> > beeping the horn.
> >> > But
> >> > that may or may not be entirely unrelated.
> >> > Any other suggestions on what to check with the ground path?
> >> >
> >> > Chris
> >> >
> >> >
> >> > On Wed, Mar 14, 2012 at 5:23 PM, Tad <tadc at europa.com> wrote:
> >> >>
> >> >> Chris, I'd start with checking the ground path between the starter
> >> >> and battery.  It sounds like you've got a bad connection that is
> >> >> backfeeding current through whatever path is available (the TPS
> >> >> wire in this case).  Not sure how the GP relay fits into the
> >> >> picture though...
> >> >>
> >> >> On Wed, Mar 14, 2012 at 2:02 PM, Chris Jude <vegbenz300 at gmail.com>
> >> >> wrote:
> >> >> > Folks,
> >> >> >
> >> >> > For the last couple weeks I've bee having an occasional no start
> >> >> > situation with the 85 Jetta.  It's not every time, but
> >> >> > occasionally the car wont start, and sometimes it won't start
> >> >> > and there will be a small puff of smoke from the fuse box area.
> >> >> > I've noticed that the insulation of the Brown wire going to the
> >> >> > throttle position sensor switch is melted.  When I remove the
> >> >> > glow plug relay the car will crank and start fine (sans glow
> plugs).
> >> >> > Last week, after this happened a couple days in a row, the
> >> >> > battery died.
> >> >> >  I
> >> >> > tightened up a wire going to the alternator and that seemed to
> >> >> > fix that problem, and the car started regularly for several
> >> >> > days, no problems.
> >> >> > Today the problem came back, with some smoke, I haven't looked
> >> >> > yet to see if there is another fried wire.
> >> >> > Any thoughts on where to look?  I don't see any bad connections
> >> >> > at the fuse box, and the glow plug relay pins look fine.  The
> >> >> > battery is charging as well.
> >> >> >
> >> >> > Thanks,
> >> >> > Chris
> >> >> > 1985 VW Jetta NA
> >> >> > Pittsboro, NC
> >> >> > _______________________________________________
> >> >> > Vwdiesel mailing list
> >> >> > Vwdiesel at vwfans.com
> >> >> > http://www.audifans.com/mailman/listinfo/vwdiesel
> >> >
> >> >
> >
> >
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