Basics: Contact Enhancer, Dielectric Grease, Micro Files

E350 · 03-04-2015, 10:05 PM

I posted a similar thread on ford-trucks.com on this topic some time ago which I recently updated:

http://www.ford-trucks.com/forums/13...othing-vs.html

But to cut to the chase, there is this Dodge van guy on another forum who started a thread on this very topic on 07-01-2010, 09:31 PM

And he came back 4.5 years later to update it to share what he learned in the interim.

http://dodgeforum.com/forum/dodge-ra...or-to-pcm.html

Bottom line is this for all of us 7.3L van guys and others who own old vehicles: Our electrical contacts are oxidizing inside the plugs in our harnesses and in the connections to our PCMs, etc.

For me personally, for the past year I have been diagnosing a "no canbus" no start situation or various sensor "open relay" trouble codes in my wife's 2000 Dodge Dakota 4x4 4.7L gasoline engine. And have gone through 5 defective replacement PCMs since.

I just sprayed some CRC contact cleaner into the three female plugs and on the bright shiny copper pins on the replacement PCM which I just received earlier this week, let the contacts dry for a half hour -- and when put back together, the engine started immediately.

It was "no canbus" no start just a half hour earlier.

Now I wonder if all along the problem or one of the problems has been oxidation on the three female plugs on the harnesses where they connect to the PCM and that I may owe an apology to the replacement PCM provider who graciously kept sending me new replacements under warranty.

I mean put a copper wire under the hood in your engine compartment and don't do anything with it for 15 or 20 years. Wouldn't it get black, green or some other form of oxidation on it which could make electrical connections intermittently fail or fail altogether?

I will order the:

1. mini Q-Tips

http://www.ebay.com/itm/Tamiya-Ameri...3D161254844820

2. Caig DeOxit D5 spray

http://www.ebay.com/itm/Caig-Labs-De...item540ae3c3ea

3. Caig Gold contact enhancer

http://www.ebay.com/itm/CAIG-Laborat...item3f2748f8ad

4. Caig Shield contact protector

http://www.ebay.com/itm/DeoxIT-Shiel...item19ec71802a

and clean every electrical connection on the exterior on my wife's 2000 Dodge and on my 1995 Bronco and on my 2002 E350.

You guys and gals who are contemplating South American or African year-long adventures, may want to do a thorough cleaning of your connections before you embark.

On the Dodge Dakota-Durango.com forum petrock said the following about vehicle electrical issues, which I now consider very wise:

"Mechanics look to the component. Electricians look to the wiring."

Guide to Caig products:

https://system.netsuite.com/core/media/ ... ime=131852

E350 · 03-05-2015, 09:24 AM

So after dropping my wife off downtown at 6 this morning I stopped by my much smarter friend Roger's to have more coffee on his porch. He said something that put it all in perspective for me, and it may help some of you too.

"Amps can't jump."

"Volts can jump."

"But only if the voltage is high enough."

That's why in a 12v gasoline engine vehicle, 12v can't jump the spark plug gap. An induction (not Tesla) ignition coil is needed to raise the voltage (from 25,000 to 80,000 volts dc depending on the ignition system) to get the volts to jump (i.e, arc. i.e., spark) that spark plug gap.

It is my understanding that those little PCM pinouts receive and transmit at 5 volts or less. Some maybe at millivolts. And it is not merely an "on-off" signal. It is an analog signal where the voltage may be (just guessing) increasing and decreasing millions of times a second from just a few millivolts up to 5 volts.

"Millivolts to 5 volts can't jump."

So a direct contact from the copper pin to the copper receptical is required for a consistent signal to be received by or sent from the PCM.

That is probably why landyatch318 commented in his thread that not only did his engine start after he super cleaned and protected his PCM contacts, but his engine idled and ran more smoothly, maybe even saving some fuel. Because a PCM which is fully and consistently receiving or sending the entire range of millivolt to 5 volt signals is monitoring and controlling the engine fueling and other processes just that much better.

E350 · 03-05-2015, 09:42 AM

I wrote the title of this thread that way also to make people think of the proper use of dielectric grease.

Because my understanding is that "dielectric" grease is an insulator (just like a dielectric coupler which stops galvanized pipe from corroding copper pipe) meaning that it has the potential to prevent the passage of electricity from the male contact to the female contact in an automobile electrical connector.

I came across this thread about the use and non-use of dielectric grease in wet or corrosive environments such as in the adventure motorcycle world.

http://www.advrider.com/forums/showt...=533996&page=1

Check out post #9 on the first page. This is how it starts:

"Using Dielectric Grease on connectors.

A lot of people use dielectric grease on connectors. Some people mistakenly believe that dieletric grease is a conductor. In fact, it is just the opposite; it is an insulator. Dielectric grease is typically made of silicone grease.

As an insulator, dielectric grease is good for use on spark plug boots. This was one of the original applications on vehicles when the high-energy ignition systems came out. It can help insulate the connector and, in particular on a motorcycle where it can get wet, it waterproofs the spark plug boot. And, because it is silicone, it is fairly stable at high temperatures and won't affect the rubber and plastics.

So why would you put an insulator on a connector? The idea is that you use a thin layer. When you push the connector together the grease is pushed out of the way enough to get a connection and the surrounding grease then keeps out water and oxygen. The connector will be protected from the environment and less likely to corrode. Plus, the silicone is safe for the plastics and PVC insulation.

That sounds good, so far; so why not smear it on everything? Well there are a number of good reasons."

Finish reading the rest of that post, then take a look at the discussion of contact enhancers on page 2.

boywonder · 03-05-2015, 01:38 PM

...that's why it's quite difficult to kill yourself with 12V............dielectric strength of your skin......volts below about 40V or so don't jump very well...the downside of low voltage is that to make real power you need lots of amps which requires fat wires and the resistance of the wires makes waste heat (measured by voltage drop from one end to the other...)

The Caig DeOxit stuff works extremely well at removing oxidation off of contacts, batteries, etc. It's expensive but in my experience so far nothing else comes close....miles different than contact cleaner, etc.

Ford_6L_E350 · 03-05-2015, 01:40 PM

When connectors are exposed to the elements, contacts can (and do) corrode and stop passing lo voltage signals. Frequently simply undoing and redoing the connector will re-establish the connection as the contacts wipe across each other.

What the dielectric grease does is shield the contacts from the elements the air, thus preventing corrosion. You can do the same with nearly any grease. I always coat my battery terminals with automotive grease to prevent corrosion. Or you can buy a commercial product to seal the connection.

Mike

boywonder · 03-05-2015, 09:23 PM

Corrosion/oxides........

All oxides happen to be insulators.....ie very low conductivity.

As we all know Iron Oxide (rust) makes for lousy electrical connections.

When aluminum is anodized, it's surface is covered with an oxide. Sometimes it can be difficult to determine if something has been (clear) anodized. One way to determine this is to check it's resistance with an ohmmeter. Raw aluminum is a very good conductor (very low ohms/resistance) and anodized aluminum is a very poor conductor (very high resistance).

E350 · 03-06-2015, 09:32 AM

So a direct contact from the copper pin to the copper receptical is required for a consistent signal to be received by or sent from the PCM.

More from petrock: "You're on the right track here with figuring out what was going on with your PCM(s), but its not a problem with the voltage jumping/arcing. The problem is with resistance. Corrosion causes resistance in the circuit. Voltage is needed to overcome that resistance (as described in one of the RealFixesRealFast Voltage Drop videos I linked to in your other thread). But in overcoming that resistance some of the voltage is ‘consumed’. So you’ll have full voltage (whatever that may be) on one side of the resistance and considerably lower on the other. With the low voltage going across the the sensor circuits, a tiny amount of resistance can ‘consume’ that low voltage and render the circuit useless. That is the essence of voltage drop and Kirchhoff's Voltage Law.

http://en.wikipedia.org/wiki/Kirchhoff's_circuit_laws

As for contact cleaner vs dielectric grease, I agree with RalphP. Its not a one or the other type deal. They are best used together. However, I’ve never really been a fan of contact cleaner sprays. I prefer a very tiny set of files I picked up a long time ago somewhere in order to file off any corrosion I find on contacts and then apply dielectric grease to it to protect it from future corrosion. But to each their own."

Personally, I am just amazed that since using the parts store CRC QD Electronic Cleaner earlier this week that I have been able to drive around in my wife's Dakota which now has no P0136 trouble code, no "no canbus" issue, and no "unable to establish link" to the H.F. code reader. I will look for the micro files which petrock suggested but I am afraid of putting anything stiff into the recepticals for fear of widening them. (I can be hard on things.) So I will probably just super clean and protect all the pins and the recepticals with the DeOxit line of products and then put dielectric grease at the exterior junction of the plugs to the PCM recepticals and hopefully call it good.

E350 · 03-06-2015, 07:41 PM

landyatch318: added the following in response to my post in his thread which goes into detail regarding how to clean the contacts and describes what happens when dielectric grease gets old:

"I didn't start this thread, but I did contribute to it 5 years ago with some advice I shake my head at now.

The CRC QED cleaner is good for flushing out old dielectric grease, but some physical removal might be needed too, to get the old ugly hardened grease inside the sockets. Try a sewing needle with the eyelet inside the socket to assist mechanical grease removal.

This grease seems to form a clear flakey crystally substance when the pin/socket connection is weak and gets hot and possible arcs between pin and socket wall.

Really get a strong light and a magnifying glass and get a look into the sockets. There are two protruding arms which are supposed to grasp the pin tightly. These get weak, and get weaker every insertion removal cycle. I used a sewing needle to assist in old grease removal along with the CRC, and also to rebend these tangs inward to exert more pressure on the pins.

Afterward when I used the Caig deoxit and the precision swabs on the interior of these sockets, they turned black with oxidation, despite a thorough cleaning with CRC.

I am at over 2 months stall free driving, after reflowing the solder on my circuit board. I shake my head at my former reluctance to do this task myself. The trick is a good clean surface and a good soldering gun so one does not need to keep the iron on the board for too long..

If you can grasp the Pins on the computer with some tweezers, and they move visibly more than 0.5MM when torqued, your ecm/pcm likely also has broken solder contacts on circuit board. These take a while to redisplay their true intermittent nature after a connector reseating.

And connector reseating is part of the issue of why the solder contacts break.

The Caig products are also lubricants, reducing the stress on insertion and removal.

I've opened up many a connector since my last post in this thread, and the amount of oxidation and crustiness inside the contacts of many of them are horrid, despite being encased in dielectric grease. Whats worse, is one cannot see how bad the contacts are, because of all the grease.

I got one can of D5 DeOxit that is no good. No oily pink residue after the solvent evaporates. The pink residue is the magic juice, so if your can does not have this, contact them.

One can also buy the d100 in the bottles with the brush applicators instead of the sprays. After application, give it time to work before coming back and assisting oxidation removal with precision swabs.

Drug stores sell the mini bottle brushes in the tooth care aisle that are great for getting inside connectors, assisting grease removal and spreading Deoxit evenly inside while abrading the oxidation as well."

E350 · 03-07-2015, 11:43 AM

http://www.ebay.com/itm/171023369312

vs.

landyatch318:

"I would recommend not abrading the interior of the sockets with the files. Apply some DeOxit d5 or d100, let it work for an hour or two, then wet the micro q tips with more deoxit and clean out the oxidation. The first few precision swabs will get all torn up and turn black, but by the end they will come out clean and pink and the interiors will shine like oiled chrome.

Any filing will dig microscopic grooves and actually compromise conductivity long term. Also the connectors are tin coated copper, and the spring loaded arms, if filed, will have less spring tension to exert.

Stick with the DeoXit and precision swabs, IMO"

E350 · 03-10-2015, 10:37 AM

Apparently there is a big controversy with suspicion among those who advocate the micro file mechanical removal of corrosion and those who advocate getting the expensive chemicals for dissolving the corrosion:

TazRango: "I bet "landyatch318" sells Caig products or works for Caig. Trust me, you don't get a nice shiny connector back after its been corroded. Corrosion eats the metal and you have to either use something abrasive to get back to clean metal (just like grinding away rusted steel) or use a chemical converter (does not actually remove the rust, but converts it to something else like iron phosphate). Deoxit is basically overpriced denatured alcohol and naphtha (Zippo fluid) in a really expensive Qtip.

Deoxit has been hawked in computer repair circles for years for cleaning memory and expansion card contacts. People who spend hundreds of dollars on Monster cables swear by it.. Denatured alcohol is a fraction of the price and works just as well - if not better since it doesn't leave oily crap on the contacts."

Experiments with pictures to come! I just got the (expensive) DeOxit products in the mail today so I will be doing a before and after experiment comparing their effect with the effect of Home Depot bought denatured alcohol. And I am going to start with my Bronco's OBD test port which is under the hood and easily photographable. If neither work, I will move on to micro files and post those results.

More to come...