https://www.youtube.com/watch?v=O-ymw7d_nYo
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My father was an electrical engineer in the automotive and aerospace industries. Fresh out of school, he went to work on the Apollo program.
He hated OE automotive electrical systems, thought they were very substandard. It wasn't unusual for him to rewire the cars we had over the years. Aircraft grade connectors and breakers were par for the course. His race cars and street cars were electronically sophisticated and very stable. His mechanical repairs, not so much. ;)
NASA workmanship standards are good stuff.
My grandad always had a binder full of this on his workbench, now I keep a few pages bookmarked: http://workmanship.nasa.gov/lib/insp.../frameset.html
Sometimes the lineman's splice is the only way, especially when splicing between different gauges or splicing into the middle of a signal wire for a test point. I actually used it today to splice into a CAN bus.
I will add my $0.02
SOLDER VERSUS CRIMP:
If you have a connection that will have movement in the wire, cable, or harness (such as connections to the engine) you should try to utilize a "crimp" connection and not a solder connection. A solder joint can wick up the wire to join the wire strands together to eliminate flexibility. After repeated flexing the wire will break where the flexible wire that is not soldered meets the wire strands that is soldered. If you must solder, make sure to provide the wire/cable with strain relief to prevent any stress or movement at your solder joint.
Always have extra wire behind a connector so they at least have a slight loop to them. This reduces stress on the crimp or solder joint. The wires should not be tight.
ONLY USE SENSOR SAFE SILICONE RTV GASKET MAKER ON ANY WIRES OR CONNECTIONS.
Regular silicone gasket maker is corrosive to wiring.
FRETTING CORROSION - Basically this is a condition that can occur to contacts within a connector due to vibration or from movement due to temperature cycling. (and other technical reasons)
Electrical contacts are typically plated to reduce long term surface corrosion. If mating contact vibration or movement occurs regularly then the surface plating can get worn. When the plating gets worn then corrosion can form. As the corrosion starts to form the resistance gets higher and higher until total failure. If that connection was a sensor you would be getting all kinds false inputs to your ECU during that corrosion process. What is interesting is that if you unplug and plug a mated connector that had either high resistance or failure due to fretting corrosion, the connection would then function properly. (well for a while anyway) Then the corrosion cycle starts over again except at a faster pace.
The best preventive maintenance that us car guys can do is fill the mating connectors with DIELECTRIC GREASE that you can purchase at the auto parts store. The grease will coat the contact surfaces to isolate it from air, water and other corrosive environments. It is not a fix all, but it really, really helps.
But what about insulating that splice?!?!?!?
It's from Make, they don't do that. It's not about making it good or practical, it's about making a bluetooth drone work on a 3D printed breadboard from a Raspberry Pi and integrate with the Internet of Thingstm.Quote:
Originally Posted by revlimiter
Ha!...I learned something new!
That is fine for solid core wire. But how much of your MX-5 has solid core?
If you want to make a solder joint in fine strand copper wire there is a difference. Slip on some heat shrink that will seal it completely. You strip it back and the split each end into three even sections of strands. Meld them to where they do not overlap the insulation. Twist them together tightly and solder the union. Then slide the heat-shrink down (after the union has cooled and coated with a thin layer of dielectric grease) and use you favorite heat gun or mini-torch sparingly.Just seal it.
As for connectors... All NASA here! I'll have to get the part number from NAPA tomorrow. But to help with the 'Tin-fretting' that was mentioned this stuff was created by NASA (Shot your ass out and you came back in a fire-ball guys). Dialectic grease has its place. But if the is an important sensor use the Stabilint 123 <will check the part# tomorrow> as the instructions say and then dialectic for the weather seal.
Ok. Tossed on my .02! And I hate electrical gremlins!!! As a mechanic they are the biggest loss of time for diag. with all the new 'safety' systems. { read in making Americans fatter and lazier systems}