Date: Wed, 6 Feb 2013 12:12:17 -0800
Reply-To: neil n <musomuso@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: neil n <musomuso@GMAIL.COM>
Subject: Re: No Start Cause: Relay Failure. PICS, Thoughts.
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Thanks Dick and David.
Thanks *very* much for insights into what may have happened. Yes,
maybe that solder joint was re heated. The insulated female terminal
from 30 to relay shows what may be a slight small burn mark.
The replacement 109 relay is a different design; the pins go directly
to the internal parts. Which begs a question:
How do I know which way the relay box goes back on the relay base?
Other relays have the diagram lining up with the 87 pin side but that
may not mean much.
Bad me, I didn't note the box position while eye balling the 109 relay
with trouble light and magnifying glass last night. A small notch on
the box coincides with a notch on the relay base, so I positioned the
box this way. My concern is that the formed bits inside the top of the
box may interfere with the switch if not assembled correctly. Seems
not but.....
Maybe the newer relay design was an improvement but points on
vibration and lack of relay socket are well taken and appreciated.
This was something I'd wondered about.
Since this was my first time at a swap (or work of this magnitude), I
went with OEM wherever possible. I assumed the 109 relay had some more
complex electrical "voodoo" going on so I made a point of using that
part. Same with fuel pump relay. The ABA fuel pump relay has large
30-87 terminals and a small 85 terminal (ECU) so a generic relay block
was of no use. The 109 also has the small 85 pin. IIRC, I had been
using a relay socket for the 109 along with a separate wire to 85 pin.
Yes. Seems so. Image:
https://sites.google.com/site/tubaneil2/PowerRelayDiagram.jpg I
don't recall when or why I deleted this socket.
For the record, the FP relay seems to be fine, though *maybe* it sees
less current going through it? (fuel pump and HO2S relays share the
circuit)
Maybe I'll use WBX 53 relays or at least a more "standard" 40 Amp
type. They will fit a FLAPS type generic relay socket. Both the Jetta
Power Supply and Fuel Pump relays have a suppression component
(appears to be a resistor) in parallel on 85 and 86 so I would make
sure a substitute relay has same.
Neil.
On Tue, Feb 5, 2013 at 11:44 PM, Dick Wong <sailingfc@dslextreme.com> wrote:
> Neil,
>
> From the looks of the solder joint, the "extra" flux (brown stuff) that is
> visible around the solder pad indicates that someone was in there soldering
> that very joint before. So someone else had the same problem. The crack
> looks to be jagged with some wrinkles on the surface of the solder around
> the break (nice pictures). To me this means the joint cracked due to
> mechanical stress and heat. The mechanical stress may have been from
> vibration. Check the contacts of the relay too. If the contacts are pitted
> and dull there probably is a lot of resistance and that causes high heat.
>
On Wed, Feb 6, 2013 at 1:34 AM, David Beierl <dbeierl@attglobal.net> wrote:
> Fascinating. As Dick says, the flux suggests prior rework. The first image
> clearly shows a large melt zone caused by arcing around the terminal
> (delimited by the curved line midway between the terminal and lead), and in
> the second there appears to be a fracture zone around the righthand lead as
> well, not surprising under the circumstances. Since 63/37 solder (which
> solidifies abruptly) is expensive, the solder used in the wave tank will
> have had a mushy zone between solidus and liquidus.
>
> This relay clearly was not designed to be used without a socket to
> mechanically support the terminals, and/or the mechanical staking of the
> terminal into the relay baseplate has failed. I'd suggest getting a socket
> under it or its replacement if at all possible.
>
> Yours,
> d
--
Neil n
65 kb image Myford Ready For Assembly http://tinyurl.com/64sx4rp
'88 Slate Blue Westy to be named.
'81 VanaJetta 2.0 "Jaco" http://tubaneil.googlepages.com/
Vanagon VAG Gas I4/VR Swap Google Group:
http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines
