"Grounding mod" - Major Improvements!

[schspeedster]

Used a Dremel with wire brush wheel to shine up connectors, coated with No-Ox-Id paste, reassembled. I would guess the factory grounds were just fine from the factory, but degrade with corrosion.

No-Ox-Id is used for critical applications like telephone central office electrical connections:
http://www.sanchem.com/ox.html

[LondonThing]

Used a Dremel with wire brush wheel to shine up connectors, coated with No-Ox-Id paste, reassembled. I would guess the factory grounds were just fine from the factory, but degrade with corrosion.

That's my take on it too, though one small rider is that I had an equivalent oddity on my other (part-owned) estate car (a Citroen CX Safari DTR Turbo - MUCH rarer than the Legacy!). In this case, because it's a diesel, the electrics are a bit... rudimentary, shall we say: anyway, in this case one of the major earths had an earth lead coming into it from an added-on system - either the driving lights or the rear washer, it's hard to say. Anyway: the master electrician who built the thing didn't make off the end of the lead into a connector: he just wound the bare wire round the bolt and then mashed the big washer from the battery neg down on top of it by over-tightening the bolt - to the point where the round strands of the lead were actually flattened by the force.

This made loads of things misbehave, because the major earth point from the battery neg to the transmission case was choked down - the strands of the new lead made a resistance point, with insufficient cross-section to pass as much current as the flat of the correct washer/ring terminal setup. taking this out and building it a proper connector, and putting that up under the bolt head with the real earth terminal flat against a cleaned-up area of block, improved the whole of the electrical system no end.

Moral is: don't stick in an earthing mod before you have been round all the existing earths and gvien them a very thorough clean-down and a look from the perspective of asking yourself: "how could I improve current flow here?"

One earth point on the Legacy had a grip washer which sank into the paint below and the bottom of the connector on the earth lead; once again, this provided a contact but only with a very small cross-section. Scrubbing the paint away from the metal, cleaning up the threads of the earth bolt, and smearing copper-slip grease over things made the earth a lot better without the washer...

[IronMonkeyL255]

What size ring connectors did you guys use?

[LondonThing]

What size ring connectors did you guys use?

Uh.. the ones that fit the bolts....

[vrg3]

Bolts with 10mm heads typically have 6mm threads and so will hold 1/4" ring terminals neatly.

Bolts with 12mm heads typically have 8mm threads and so will hold 5/16" ring terminals, though they may need to be filed a little wider.

[sammydafish]

Yes, you can do that... Measure how much resistance there is.

the better way to do this is to measure the voltage to a known ground while the item in question is under load. A wire can have a good ground when there is no current going though it, but turn to crap once you send 30 amps though it. If there's a significant voltage drop over the wire, it's no good (multimeter measures voltage from testing point to ground)

[simbey1982]

Hey this is a great thread, sticky this thing!!!!

[Legacy777]

Anyone can add a link in the general sticky thread

[RJ93SS]

so has anyone had any more conclusions or thoughts, thought i'd open an old thread and what else has been done over the past three years, i recently relocated my battery to the spare tire area and ran 2 gauge welding wire to the starter, ran a 8 gauge power wire from the engine fuse box to the starter, and ran two battery grounds, one from the terminal to to the bottom back of trunk floor and one directly to the frame at the back of the car.

i also cleaned most of my other connections and ran a heavy duty 4 ga. from the starter to the body, i am thimking i should do some alternator, coilpack, and maybe even some exhaust grounding?

thoughts or ideas

[morgie]

Hi,

just updated the link to the pics in the first post.

[tturnpaw]

If the grounding is done from the engine to the chassis, then a couple connectors from the chassis to the battery, it will make an improvement. There is a reason they sell a main junction where all the wires bolt up to create a central ground. Hence why a kit is better.

Many people have seen a hp or two and some tq on the dyno. Most just state that everything runs smoother. I have a kit on my ea82 and it seems to run very smooth.

[Mikerthebiker]

just did this, seems to have helped the hesitation, did the same hookup as morgie, windows and all electrical seems to be working a little better!

[originalcyn]

Wow, I feel like a jerk for asking this a bajillon years later. I know without a doubt that the way that morgie has it set up is correct and works for everyone. However, for the sake of vanity and wanting to run less cable to the negative terminal on the battery, would it work in this alternate configuration? Thanks for indulging me, and please forgive my ignorance and presumptuousness.

Oh, and the "ground post on chassis" is really just anywhere i can make a clean ground on the chassis. it doesn't have to be right there.

[Legacy777]

Honestly,

In my opinion you be best served by adding extra grounds where the factory grounds are: Starter, chassis, and run a new lead to the ECU ground point on the intake manifold. That should take care of the majority of things engine related. The extra ground on the intake manifold where the ECU grounds is probably the most important.

[TBFK]

Ok, let me start off by saying, like other people mentioned, Legacy Central is extremely helpful!! I really appreciate all the help I get from this Website, and i'm sure a lot of other people do as well.

As far as the ground mod goes...I've had hesitation issues between 750 and 2,000 rpm's, and my lights are dim at low rpm's. Also when i'm driving in the mountains, I have my high beams on, fog lights, stereo, and heater, and my car will die. I had my alternator checked, and i'ts working great. So I will try this Ground Mod, and see if it helps, I'll let you guys know if it does.

[TBFK]

So I will try this Ground Mod, and see if it helps, I'll let you guys know if it does.

Well I wasn't able to hook it all up because I ran out of wire and didn't have all the right size connectors. But I did get the engine, driver's side strut tower, and the transmission grounded. It has helped the issues I have with my car quite a bit. Now i'll just have to finish the job after work today.

[cj7135]

I am having the same issue. I think i may try the ground mod. My vehicle is a swapped EJ22T into a 97 legacy wagon. I'm no so sure my wiring buddy was very ground-conscious while installing the Turbo ECU, i'll have to check. I'm 99% sure he used a bungie cord to hold the ecu into the dash.

I REALLY hope this helps, especially since my OBD I diagnostics connector disappeared. Does anybody know a way to hot-wire the ecu into giving you the stored codes??

Any help is greatly appreciated.

[Legacy777]

You just need to ground the pin for the diagnostic connector. This diagram shows the ECU I-O.

http://www.surrealmirage.com/vrg3/ecupins/

B56.12 is the read mode pin, and B56.13 is the active diagnostic mode pin. Start with B56.12.

[cj7135]

PERFECT! Thank you so much that's exactly what i needed.

I got about 6 different codes, and then none. I pulled the ECU, rechecked all the wiring, and figured i'd squeez around with the car running and see if any of the connections are loose. Sure enough, I squeezed the wires and it clicked on, then i let them go, it clicked off. I retested my theory about 15 times, and eventually after wiggling every wire, i found a large square terminal block, sort of like a connector. I'm not sure if that's from the 93 or the 97, but there's a bit bolt through it. I tightened the bolt with my hand, and now i'm doing 200 like a sick joke.

Symptoms:
- Fans running on cold start intermittently
- Very difficult to start while fans are on
- 600 RPM idle on cold starts
- Headlights Dimming Intermittently
- Intermittent CEL with loud clicking under dash
- Hesitation while CEL is on, and no problems when it's off.
- 15l/100km highway

I thought it was the coolant temperature sensor, but I changed it. Then I did the grounding mod, then i checked the wiring.

I don't know if these terminal blocks with the big bolt through them are on the EJ22T harnesses usually, but if they are, i would definitely check to see if that bolt is tight. Seems like it could shake loose easily. Worth a look, mine runs so good now and i get 8.5l/100km, and thats a lot of time in boost too

[Legacy777]

Thanks for reporting back. That junction with the bolt is called a Super Multiple Jumper (SMJ). They are found on the stock Legacy wiring. I would suspect when the EJ22t was swapped, they may have not tightened that bolt all the way.

[Mattheww044]

OK i started the grounding mod tonight, didn't quite finish it though. It seems to have made my headlights a bit brighter and also seems like it runs smoother, but it's such a small difference that it could easily be the placebo effect.
I ended up getting this grounding kit off of ebay. It was only $25 shipped, and came with several wires with terminals already spliced and heat wrapped, all of the hardware needed, and a "junction box" which is the main reason I bought it. It sits over your ground terminal on your battery as the stock one would, and has a "ring" with several holes to bolt each of the grounds to. here is a link to the one I bought.

http://cgi.ebay.com/ebaymotors/ws/eBayI ... 398wt_1165

The only complaint that I have is that the head of one of the bolts snapped, after applying very little pressure to it, literally snapped the head in half. It isn't a huge deal considering I only paid 25$ for everything, but all of the other bolts were fine so I wouldn't say I'm dissatisfied.

All of the grounds are going straight to the battery ground terminal, and I used a dremel with a "wire brush" tip to clean up all of the stock bolts and mating surfaces.
So far I just have:
Battery- Chassis right behind drivers headlight (I ended up using a much larger wire there 4gauge i believe)
Battery- Long Bolt that goes through the alternator and AC Compressor
Battery- Passenger side plug wire bracket
Battery- Driver's side strut tower (with the factory ground)

I still need to do:
Battery- Knock Sensor, Starter bolt, and the manifold where the ECU grounds. Probably will ground the strut towers together as well since I have access to all the wire I will ever need. (Hey! maybe being an electrician does pay off!)

Where exactly does the ECU ground on the manifold?
Is there anything else that I should add to the list?

[Mattheww044]

OK just finished the grounding mod. I did the knock sensor, ECU ground, Starter ground, and strut towers to each other.
My car is running way more smooth, what a great feeling. I really just wish I could get into boost (doing my clutch next weekend).

[free5ty1e]

I may just be an idiot (very likely) but I am having a hell of a time locating the ECU ground. It's been a while since I've been back there and replaced the knock sensor, actually at this point I'm not even sure where the knock sensor and coolant temp sensor and all that back there that I should know locations of.

I've been searching around and can't seem to find the information my brain needs to tell me "Hey Chris! That thing there - that's the ECU ground you need to run to the battery ground!"

Anyone got a decent photo with some description of what I'm looking for, or a diagram, or something with some reference parts I can use to find the ground?

I'm doing the strut towers, behind the drivers headlight, and under the coil pack for now. I have plenty of wires and ring terminals and have spent what seems like a lot of time trying to clean the grime from my engine bay so I can better identify things, but at some point I'm just gonna have to call it good for now and move on lol

[Legacy777]

This picture shows the area where the ECU ground spot is

http://www.main.experiencetherave.com/s ... Ground.jpg

It's on the bottom back side of the intake manifold #4 intake runner.

[free5ty1e]

Ohhh lol no wonder I couldnt find it. I will have to get that one another time when I have things more.... apart.

Got good clean grounds added for L&R strut towers, fuse box (changed from behind driver headlight as that screw sheared), and coil pack. I wire brushed all of the contacts, even the bolt threads which seemed to make them easier to put back in anyway. Left a light coating of dielectric grease on all the finished grounds to discourage corrosion. Reassembling now - had it apart for the spark plugs & fuel filter I just replaced so I did some of the grounding mod while I was in here.

Thanks Josh for the most informative photo, as usual.