Gold Plated EFI contacts

[j-c-c]

Not sure if this is the right forum. In my line of work in the technical side of the concert industry, anything electrically connected that's important, and is not connected under load, pretty much has gold plated contacts. This is not new technology, and is likely lifted from aerospace or whatever, decades ago. I'm moving towards a installing efi systems in my cars, and have heard all the horror stories on lousy grounds, etc. But the odd thing, seems like little use of any gold plated contacts. I am sure the top line Motec, etc is on board with this, but its pretty scarce the places i have looked. The cost, because of the small amount of gold is not a lot, likely more the process/effort. I would think reduction of customer support calls and the sizzle of gold plating connector contacts, would be enough of an upside. Anybody make the effort to plate their own or upgrade their connectors, in critical areas?

[peejay]

Practically ALL installation faults I have seen were due to REALLY bad installation. Crimping cheap spade connectors with pliers, trying to ground through paint, grounding things at random locations instead of a centralized location, etc.

The only "connection" problem I ever had was when an MSD crank trigger connector unplugged itself. Crappy design. I ziptie them together now, since I never got arsed enough to convert them to Weatherpak.

Gold contacts are only a benefit if corrosion is a liability. Good automotive weatherproof connectors make them unnecessary. If you wish, you could put a dab of Stabilant on each female terminal when you assemble.

[user-23911]

It all started in the telecomms industry.
Small signals are usually AC and metal plugs and contacts tend to have an oxide layer which in turn has resistance.
A good example of that is phono plug in a guitar amp, a phono plug was originally a plug for a manual switchboard.
The original ones were brass and needed cleaning regularly, gold is better. It doesn't oxidise so doesn't need "contact wetting".

With AC signals, "contact wetting" is often used, that applies a small DC to the AC signal and overcomes the contact resistance.
Your phone line is 50V DC at 15 to 20 mA with a AC signal over it.


When it comes to cars and computers, most of the signals have a DC bias so there's no reason to have to use gold contacts.
Most, not ALL.

BTW everything should be soldered, NOT crimped.
Crimping is quick, cheap and very nasty.


Lousy grounds?
The usual ricers bring that one up all the time.

The only time you really get a bad ground is in lighting circuits when you get a dim bulb. That's when the body of the bulb has rusted and so the circuit is completed by grounding through the adjacent circuit, that's where one bulb has 2 filaments in it.
It's just a case of cleaning the bulb and the socket.

[pamotorman]

connections have to get pretty bad on a car before things stop working. this is the chassis ground connection from a C-5 corvette.

[peejay]

BTW everything should be soldered, NOT crimped.
Crimping is quick, cheap and very nasty.

Well, I've got five or six seasons of off-road competiton with one of them Megasquirts, plus quite a lot of street miles, and I assembled the wiring harness with butt connectors from a flying-lead harness to salvaged connectors. Zero faults. I did it this way because my soldering skills were less than good and I knew that I could do a good crimp connection.

I've been working on soldering skills, though, for two reasons. It makes wire bundles easier to package, even if you carefully stagger the butt connectors. And it is a lot cheaper. A decent soldering gun is only $50-100, solder and spools of heat shrink tubing a very cheap. Meanwhile, decent butt connectors are a dollar each. That adds up very quickly!

All the same the connection issues I've seen would bring you to tears. Like a TPI-equipped Corvette that would stop running when hot. Determined that it stopped getting fuel. After various tests, pulled the plenum off to get to the injector connectors and found that whoever wired in the computer (something expensive, I recall) just twisted wires together and wrapped in duct tape. Which became conductive when hot, killing the injectors...

Lousy grounds?
The usual ricers bring that one up all the time.

And I've seen ECUs grounded by wrapping a twist of bared wire around a sheetmetal screw and zipped into a painted roll cage tube, with other components grounded similarly wherever was closest. "But wire is expensive and I'm trying to minimize use." $1500 computer, $2000 in hardware, and trying to save $10 on wire...

[BOOT]

Clean the metal and use an antioxidant like dielectric grease for a multi prong connector or copper anti-seize if it's a grd.

[Paul Rig]

You can add Do not twist wires before crimping or soldering. This is where DIY'ers make the biggest mistakes.
When you crimp the wire it is supposed to conform to the saddle and crimping machine.
When you solder the tin/lead is supposed to flow around each strand of wire.
If you twist the wire tightly lead flows around outside and small movement vibration will cause bad connections. Same with connectors.

and FYI the military standard prefers crimped wire over a soldered joint.
1 twist in 2inches for crimp and solder at the most

[modok]

Gold+solder=brittle joint. So, avoid that!

Really NICE crimp connectors work very well, and crappy ones don't. Just like everything else. Done right it's a lovely thing but everything can be done wrong too.

Appropriate size connectors for the current carried is important. Of course too small and it will burn up, but the opposite is bad too. If the connection does not transmit enough current to keep itself connected then might consider gold plating OR just some kind of connector that has good spring force over a smaller contact area.

[Circlotron]

grounding things at random locations instead of a centralized location, etc.

Amen to that!
Earth loops aka ground loops are probably one of the least understood thing by people who work with electrical installations of one sort or another.

[Circlotron]

BTW everything should be soldered, NOT crimped.
Crimping is quick, cheap and very nasty.

A good crimp connection is extremely reliable.
So is a good soldered connection.
Some of those cheap crimping tools are just junk. A good (read: expensive) one will squeeze the lug onto the wire hard enough to cause localised microscopic welding of the two metals.
Soldering is not always the best solution in a high vibration environment. The molten solder wicks up along the stranded wire and ceases abruptly. This transition can then become a flexing stress point leading to a fractured wire, often inside the insulation. By all means use soldered connections on a car but make sure they are secured from moving around.

[oldjohnno]

I've tried all sorts of (mostly ratchet type) crimpers over the years, and with all of them found that occasionally I could pull a joint apart with a bit of effort. So a couple of years ago I bought some Thomas & Betts WT111M pliers and you could tow the Queen Mary with the joints that these make. They might look crude and old-fashioned but they certainly make a tight and secure crimp. I'll never go back to ratchet crimps.

[user-23911]

Nothing beats solder.

Yes crimps done properly work well, that's using the correct materials and the correct tools
BUT

Nothing beats solder.


Crimps are used for one reason and only one reason........cheap and quick. Time is money.

2 reasons actually.........some wires can't be soldered.
But that doesn't apply to cars.

[Circlotron]

2 reasons actually.........some wires can't be soldered.
But that doesn't apply to cars.

The ballast resistor wire on older cars might be hard to solder, but that's about it.

[oldjohnno]

Nothing beats solder.

Yes crimps done properly work well, that's using the correct materials and the correct tools
BUT

Nothing beats solder.


Crimps are used for one reason and only one reason........cheap and quick. Time is money.

2 reasons actually.........some wires can't be soldered.
But that doesn't apply to cars.

Crimp vs solder seems to be one of those forum favorites, like "which oil?" or torque vs hp.

Personally I like a good crimp - it's quick and reliable and I know the wire isn't going to break at the end of the soldered section through vibration. I've come across this a few times. An aviation mechanic friend told me that soldered joints in aircraft are generally not permitted for this reason; it's crimp or mechanical connection only. Really though I think either is fine if done properly - crimps need to be tight and secure, soldered wires need to be secured against vibration.

[Calypso]

I've tried all sorts of (mostly ratchet type) crimpers over the years, and with all of them found that occasionally I could pull a joint apart with a bit of effort. So a couple of years ago I bought some Thomas & Betts WT111M pliers and you could tow the Queen Mary with the joints that these make. They might look crude and old-fashioned but they certainly make a tight and secure crimp. I'll never go back to ratchet crimps.

That's a great tip! It's an eternal pain to make good crimps. Gotta check this out.

Another one that has worked great for me is to buy a box of Bosch manufactured brass uninsulated spade connectors (made to be used in the plastic connector holders) for use wherever you'd need 'em. The connection fit is from an entirely different planet compared to the normal hardware store ones.