damian

iTrader: (2)

For those who are adding or renewing ground straps, I suggestion trying coaxial cable.

(I can't take original credit because got the idea a long time ago from a web site.)

Here are my simple instructions and pcitures.

Step 1:
Strip the outer rubber coating and the internal core so that all you have left is the braided sheath wiring.

Step 2:
Crop the braided wire to the length needed and crimp on end connectors as needed.

Step 3:
Clean up the contact areas and secure your new braided ground strap made from that extra coax cable sittin in your garage

(pictures below)

damian

iTrader: (2)

another pic
coax vs stock (cat/muffler ground wire)

damian

iTrader: (2)

another pic
old stock ground and new coax ground installed

skunks

man, that's so thin. Personnly I suggest you use 1-2 gauge wire for grounding, thats the only stuff I use. Go thick or go home

BTW: Is that your muffler your grounding?

ArchangelX

That's one shiny *** muffler then...

Thanks for the idea...any more pics of your grounding mods? And the locations? I haven't done that modification yet, but I do get hesitation in the lower RPMs sometimes.

Of course, I'll probably have to redo it all in a couple o' months. Gah..that sucks. Sorta.

Flybye

It should be. There is a stock grounding cable back there between the main cat location and the catback.

O2 sensors like ground, too

rxrotary2_7

hmmm....

RX7Elmo

speaking of grounding....anyone know where ALL the stock grounds are? I'm replacing all of them and i only find the UIM to the chasiis ground, and the muffler strap. Any others?

Thanks

Danny

mjw

iTrader: (1)

There are two underneath the stock coil packs/rats nest, one from the battery, and one more on the driver side of the motor down between the plugs and oil pan. I am sure there are more but those are the ones I remember.

RX7Elmo

thanks for the info. I"m going to go look for those tomorrow.

Danny

RX7Elmo

also, the coil ones..i have to take off the UIM huh....darn it.

Danny

Stevey629

Is just changing the one from the UIM to the Firewall going to help any? I don't really feel like taking off my UIM. I was wondering if beefin' up that one ground that I just mentioned would help anything. And twisting the cables like that? looks a bit messy to me, but thats just me. How do u hook up the other side of the coaxial cabel that wont have a bracket? Did u put another bracket on there, and put it underneath the stock one?

damian

iTrader: (2)

I used a hard wire to wrap the new strap to the large stock bracket that sits on the muffler stud.

The reason the new starp and stock strap are twisted together is simply because it helped keep them organized while I was bolting them in.

wonder1and

I went to home depot and got my own DIY grounding "kit" for about 5 bucks, 2' of 3g cable and some copper fittings that screw into them that have a hole for a bolt. looks good to me. We need to figure where the hell all of them are. that way we can all get'em replaced.
Ryker

spurvo

At the very start of the electrical secion of the shop manual, actually pages Z-18 and 19, there is a section that lists all the grounds, and shows their locations.

go to http://www.iluvmyrx7.com/ for more...

RX7Elmo

i'm not sure if replacing ONE ground will change much. but replacing all of them should yield a smoother, more driveable car. I saw an SCC article on grounding straps and a slightly modded FD made 15rwhp just because it changed all it's straps. This was with the use of a kit from japan however.

Danny

Stevil

Its tough to tell where the straps go by looking at electrical diagram manual.

MJW lists four ground points then the muffler one is listed. My HGS kit came w/ 5 cables, are these then the 5 cables that need to be replaced?

I noticed the battery cable contacts the chassis at the wheelwell, but that same ground continues into a grouping of wires and disappears. So is the first part just replaced? Where does the ground continue to go?

The HGS kit comes w/ 5 and the longest is 15". So, the original ground straps cant be that long.

Thanks, want to replace these today or tomorrow, I have the time, so please any answers? I guess I will take off UIM and see.

Steve

Stevil

Ok after looking at instructions for HGS kit, here are the cables to be replaced(from a sample car):
1. Cylinder head or intake manifold or surge tank
2.Transmission or cylinder block
3.Chassis
4.Chassis(opposite battery)
5.Bat neg terminal

No mention of muffler strap
All the cables connect to each other to form a chain from drivers side to passanger side

The Battery neg terminal touches chassis at wheel well, but then continues into an electrical wire cover and continues to ???. Actually the first part of the Bat term wire is 5 above and the second part would corrospond to 2 above, both connecting to point 3.
But the diagram also shows a cable going from chassis also to top of engine. The point on the wheel well, goes to bat term, transmisson and top of engine according to diagram. Yet, in our cars, there were only two wires connecting to the above contact point(which would be labled as 3 above)

Continuing my search,
Steve

Also, I think the muffler strap is more of a safety strap, not an important one like listed above to provide good current(which is the focus of the kits)

RX7Elmo

This is what i've done so far in regards to grounding...all useing 4 gauge AMP-Power Wire, and copper connects.

I replaced the ground from the UIM to Chassis. I discovered that the grounds from the ignition coils go to the UIM ground...so replacing that ground helps a lot (with the coils/ignition).

I added a ground from the rear rotor housing (block) to the chassis.

I WILL add a ground from teh transmission to teh chassis as well as a ground from the downpipe/midpipe connection to the chassis. I believe a ground on the exhaust helps the 02 sensor.

FYI, i relocated my battery to trunk and the negative is already upgraded 4 gauge wire and grounded to the chassis.

The stock negative from teh battery is curious..it goes to the wheelwell, and disappears. I went ahead and still grounded the end just to be extra secure.

RESULTS:

After just changing one ground and adding one other, the difference is amazing. Call me nuts, but my car has no hesitation, revs smooth, and i swear i have more power (noticeable more power).

Danny

wonder1and

Hey I wanted to add ANOTHER ground besides the ones that have been listed... Fuel Pump Ground.
I have noticed these symptoms latley from this ground being bad...
1) At startup the car will raise rev's to usual spot (2k?) then surge and die.
2) At takeoff from stop when engine was cold car would begin accelerating then sputter and give a good 1-2 sec hesitation in the acceleration.

How to fix this... (very easy)
Go get 2' of grounding cable
-I used 2g copper wire w/ connectors from Home
Depot
Have a soudering (sp) iron plugged in and warming up w/ some souder nearby for later use.

Walk to rear hatch, open it, flip carpet over towards from of car, (if you have bose you need to remove that section at this time) you will see an aluminum plate w/ a wiring harness coming out of it, follow it and see where it connects to another harness right under the drivers side toolbox thing (technical term). All you have to do is remove the nut holding down that part of the trim then lift up on the bottom while giving the connector a little tug. Note the whole connector wont come out it will just be exposed enough to get your hands on it and disconnect it !!!Don't let to female end slip back under!!! now take the male end you have in your hand and decide if you want to do all the work in the trunk or on the floor. To remove this part from the car you have to remove 4 screws from the plate, lift it up, un-nut the ground that you see connected to the gas tank, undo the harness connector from the tank (use a flathead and insert it on the drivers side of the harness, mush easier)
Next you will have the harness in your hand either way. Take the electrical tape off from around close to the male end that you unplugged first and keep unwrapping untill you are about 1" into the foam covering. After you have that done expose the wires by removing the wire shroud. now you should see a total of 4-5 wires two are larger than the rest. 1 is white w/ a red stripe and one is solid black.
Take the solid black one and use a x-acto knife to strip the sheathing off of it CARFULLY. Souder the wire that I told you that you would need to the black wire then perferably ziptie the two together to keep them from eventually woking themselves apart. Wrap the 2 wires in electrical tape then put the harness back together like it was. After the harness is rewrapped, reinstall it using the instructions I provided going backwords.
Now you should just have that 1 wire extra, find a suitable place to mount it. Grind the paint off the body using a dremil tool or the likes. use a ring type connector of some sort (possibly soudered together) and mount it to the stud you picked. Don't forget to put the nut back on the trim piece and your done....
~~~>(Wow that took a whole 15 min)<~~~

PM me if you have q's... shouldn't be that hard and got rid of the symptoms I listed above... nice and easy.
Take it easy,
Ryker

DamonB

The ground on my fuel pump went bad as well; pump wouldn't run at all when I went to start it one morning. Mine was the ground on the INSIDE of the fuel tank; the ground wire that goes from the pump to the connector on the bottom of the mounting plate.

I was able to troubleshoot it because I had good voltage coming to the connector outside the fuel tank. I figured my pump had croaked so I pulled it and then hot wired the pump to see if it was in fact dead. The pump ran like a top then so I knew my problem was between the plug at the outside of the tank and the pump itself. After inspecting the wires I found the worn connection on the underside of the mounting plate. I inserted new spade lugs and it's fine.

Adding another ground to the fuel pump wiring may be good, but if your connection fails inside the tank like mine did it won't help you unless you are bypassing all the connectors and going straight to the pump. I actually plan to pass a bolt through the mounting plate and attach the pump ground to it. I can the run another ground from there to the chassis.

DamonB

damian, your ground straps may be a good idea but if you are not actually using a connector at the exhaust end to terminate it you don't have a permanent solution. Just wrapping the connection with heavy wire is not going to hold up. Get an oversize ring terminal and mount it to the exhaust stud just like the stock one.

Stevil

OK, after looking at instructions and talking to Jason(RX7 store), the HGS kit just adds to the existing ground. Basically, just use the places I listed above from instructions and add new grounds. Leave existing grounds alone. No need to take off UIM or anything. So, there are 5 wires included. Just string them along from Passengers side to drivers side to battery.

So from passanger fender to UIM. UIM to say tranny. Tranny area to engine block. Engine block to drivers side chassis. Drivers side chassis to bat neg terminal.
Doing this, according to the kit, added the above mentioned performance enhancement. I am sure the others listed(muffler, fuel pump) will also help, but this is how the kit works. Jason said he felt more torque down low after install.

So there you have it. Pick your own spots and have fun.

Steve

damian

iTrader: (2)

i agree DamonB, good idea.

spurvo

Battery ground in stock form: One very weak clamp to a fairly ok copper wire (maybe 8 gauge) wherein the connection is susceptible to copper oxidation and therefore higher resistance, right from the start. Next, we travel to the aformentioned fender connection, wherein the insulation was removed from the wire and the wire crimped to the chassis connector. Again, oxidation makes for VERY poor connection here. The wire then goes into the harness, and thence to the engine block, where it bolts into a crimped connection on the front housing. Oxidation once more. Then there is the WONDERFUL block to chassis through the UIM, wherein a braided wire (aluminum?) is crimped to a UIM connector and attaches to the chassis via blade connector and bolt through sheet metal. UGH!!!

On mine: Battery negative replaced with 36" long 4 gauge coming from solid swaged connector (Shucks auto supply part) and going directly to the engine block on the front housing. Bolted using external star washer. Two extra leads come from the battery connector, and one was soldered to a 14 gauge wire that extends to the upper shock tower empty bolt location, again with external star washer,and paint lightly abraided away. UIM to chassis through 14 gauge eye connectors soldered on each end, and star washers. UIM to ECU connection (3 on the diagram, I think) soldered and star washered. Biiiig difference, though hesitation still there at 3K. Injectors mapped to cut out, so not much to do until/unless piggyback ECU add on. We'll see. Haven't attacked the rest of the grounding in similar fashion, yet.