Grounding Mod Re-visited **56K Warning**

[Andyjo]

Only 8 gauge wire? why not run 4 to everywhere?

[the_bard]

i just want to know where you got the really cool beating the dead horse thingy:banana:

 

 

nipper

OT: My smiley button (in the middle of the bar on top of the field where I type this reply in) has a link at the bottom that says something like "Showing 14 out of 25 smileys - Show all smileys." I click on that, which pops up another window. Beating dead horse smiley is on the right, third up from the bottom.

[OB99W]

Since it was revived anyhow, can I measure my ground connections with ohmometer and determine that my connections are close to zero enough that I don't need to redo the connections? What would be the magic number?

0.5 ohm, 0.1 ohm?

There's no "magic number" when it comes to resistance in ground circuits, other than "as-low-as-reasonable ohms" . That's because the real concern is voltage drop (you want as little as possible), and that's determined by the product of the resistance of the connection and the current going through it. For example, one amp through 0.5 ohm drops 0.5 volts, but 50 amps through only 0.1 ohm will cause a much more significant 5 volt drop.

 

A voltmeter can be used to check the drop across connections under operating conditions, where that's practical (it isn't always practical). Under 0.1 volt of drop is a good connection no matter what the current, since a loss of that magnitude is fairly insignificant relative to the nominal "12 volt" system. Many circuits can tolerate more loss, but if you can keep it low, it's obviously better.

[gethoht]

Could you please post pics of the completed job? I am looking to do the same thing, and a finished pic would help me alot!

 

I'm having electrical issues as well....

 

On my 98 legacy outback, the headlights dim when I crank the blower, or hit the brakes. Sometimes all the lights dim heavily for a minute or two.... i'll hit a bump or stop at a stoplight, and the lights will instantly brighten back up like nothing was wrong. I've talked with my mechanic and he says it sounds like a grounding issue.

 

I've already replaced the battery and alternator, so it's gotta be something else...

 

I need to buy a manual with electrical diagrams... anyone have a recommedation as to which is the best? Chiltons? Haynes?

 

I have a multimeter.... anyone have any advice on how to check a ground using one?

 

Thanks for any help

[OB99W]

I have a multimeter.... anyone have any advice on how to check a ground using one?

The objective is to reduce resistance. That requires tight, clean connections (free of rust, paint, etc.) having good contact area.

 

1) A voltmeter can be used to check for voltage drop across a connection. Lower is better; 0.1 volt or less under operating conditions, if possible.

 

2) If the vehicle has seen enough miles (read "vibration") and/or salt (read "corrosion"), it probably isn't worth checking for bad connections with a meter. Start with any that look obviously bad, or just work on all that can be found, even if they appear to be tight and clean.

 

3) The smoother/flatter the surfaces, the better. Only the "high" points touch, so rough surfaces minimize contact area, increasing resistance and making it easier for corrosion to get into the connection again. Even if contact-enhancing "glop" (that's a technical term ) is used, a smooth surface to begin with is preferable.

 

4) To help with 3), a metal file, wire brush, or scraping with a razor blade is preferable to grinding. If grinding is necessary due to severe corrosion, file as flat as possible afterward.

 

5) Try to avoid "sandpaper" (and grindstones); the abrasive is typically a metal oxide (which is a semiconductor), and some is left behind on the surface being "cleaned". If you must use one of these, a fine-bristled wire-brushing afterward can remove most of the sanding dust before remaking the connection.

 

6) When cleaning terminals, don't overdo it; most are plated, and the base metal under the plating is usually not as corrosion-resistant.

[Scottbaru]

A few months after I bought my '99 I decided to adjust my clutch. I found a heavy wire dangling, turns out it was the engine ground. It ran great without it, no change after attaching it.

 

What about spray-painting with zinc "galvanizing" from a rattle can to prevent corrosion? What about copper anti-sieze in the connection?

[Lawsonmh15]

I need to buy a manual with electrical diagrams... anyone have a recommedation as to which is the best? Chiltons? Haynes?

 

Thanks for any help

 

 

If you need the full set of elec. diagrams PM me.

[Green96GT]

So, just to be clear:

 

The new red wire shown in the 3rd picture goes straight from the black battery terminal to that bracket on the engine? In that case, did you do away with the ground from the black terminal to the chassis (near the headlamp) - or does one need that wire in addition to the engine ground?

 

Thanks!!

[Lawsonmh15]

So, just to be clear:

 

The new red wire shown in the 3rd picture goes straight from the black battery terminal to that bracket on the engine? In that case, did you do away with the ground from the black terminal to the chassis (near the headlamp) - or does one need that wire in addition to the engine ground?

 

Thanks!!

 

 

Chassis ground STAYS.

[Lawsonmh15]

DEAR GOD. DO NOT GROUND YOUR MANIFOLD, OR ANYWHERE ON YOUR ENGINE!!!

 

I FEEL LIKE A MORON. YOU WILL CREATE A GROUND LOOP WHICH WILL CAUSE, AT THE VERY LEAST, ISSUES WITH YOUR TRANNY.

[nipper]

Yellow is also often used as power in auto applications. Used red because of the high strand count, no other shield colors available.

 

Yellow is another poor choice since it is the color of the airbag wiring.

[99obw]

If one is going to solder and crimp, which is fine, the soldering MUST be done after the crimping. This is actually code somewhere, can't remember where for sure. If you crimp after the solder the solder will give over time and the crimp will loosen up.

 

I have a hard time believing this will improve anything, though it might mask other problems. Most mods where one assumes that they can engineer better than the OEM engineers are wishful thinking at best.

[brus brother]

OK you shamed me into inspecting my grounds. I found the connection to the engine and firewall alright but the split wire off the neg terminal where it grounds to the fender was pretty crusty. Wire brushed and reconnected. Should I coat the exterior of these connections with dielecric grease? I have been having some dimming of lights when braking and will report back if there is any change.

[uniberp]

So all this is nonsense?

 

I don't think so. With that size cable, and maybe one more back from the mainfold back to the frame, will stabilize any potential ground loop.

 

Are you saying it affected your tranny?

 

DEAR GOD. DO NOT GROUND YOUR MANIFOLD, OR ANYWHERE ON YOUR ENGINE!!!

 

I FEEL LIKE A MORON. YOU WILL CREATE A GROUND LOOP WHICH WILL CAUSE, AT THE VERY LEAST, ISSUES WITH YOUR TRANNY.