[urq] Barrel crimper?

[Buchholz, Steven]

... are you advocating the complete elimination of connectors?  Why the
Molex links?  Crimping and soldering create permanent connections ... 

Soldered connections definitely have their place ... the old urqs have
the intake air temp sensor soldered to the harness for the F/TCU ... for
good reason.  Crimped connections are well known to be robust and
reliable too.  It is possible to create a problem by doing a poor job
crimping ... it is possible to create a problem by doing a poor job with
soldering.  

The thing is that the problems many old cars have with electrical
connectivity rarely have anything to do with whether or not the
connector pins are crimped or soldered.  The real problem has to do with
high contact resistance at the interface connectors themselves.  This is
caused in most cases by oxidation, or by the connector being plugged in
and unplugged excessively (does everyone know that interface connectors
have a rated number of mating cycles?).  It is also true that there is a
bona fide design issue in the wiring of the urq.  High current with high
contact resistance creates heat ... and if you get enough heat it
creates a degenerating situation where the contact resistance gets
higher and the connector gets hotter, until the connector housing melts
and the connection is broken completely.  

The main problem I have with soldering connector pins is that the solder
will wick up the stranded wire and create a solid wire that can be
broken more easily than the stranded wire.  You can also create problems
by soldering a connector which was not intended to be soldered (usually
related to melting or shrinking of insulation).  I've also seen what can
happen if you "tin" a stranded wire *then* crimp the connector in place
... almost started a fire!  

I don't know where the owner of that "high end" car audio shop got his
impressions ... perhaps from someone else who was his mentor before that
... and that was probably based on the use of poor quality crimpers.  If
I owned a "high end" car audio shop I'd spring for the appropriate "high
end" crimpers and instruct my employees to crimp/solder as appropriate.


If you want to solder, that's fine as long as you understand the risks.
When I choose to solder a pin it is usually after I've crimped the
connection.  

Steve B
San Jose, CA (USA)
> >
> When I said use solder it came from when I worked in a high end car
> audio shop the owner said he would never buy or supply or let any
> installer use crimpers!
> And  in the 4 years I worked for that shop I NEVER saw any of the cars
> that we worked on come back to the shop for a short of any kind.
> So now on to do I own a set of  crimpers  yes I  do  I own  a  few
sets
> of  AMP crimpes  they  work  good  for  serten  things  but  when  I
> work  on  my  own  stuff  like my Urq or do alarm's I will always
solder
> all the connections.
> 
> Here is a great site on Molex plugs. http://marvin3m.com/connect/ And
> like it says:/Connectors improve manufacturing:/
> Connectors make it easier to assemble electronic products. They also
> facilitate mass production processes.