very easy diy: coilpack grounding

[Fenvy]

I remember someone on fresh alloy stated that the stock grounding of coil packs is pretty bad. I checked the resistance awhile back with a multimeter and it doesn't look so good. I don't even the exact numbers though. Since phase2 sells a product to combat bad ground, I suspect this is a common problem. You can fix it without spending like 90$ for their grounding plate

Set your multimeter to resistance mode (omega sign) and choose 2000. Check between battery ground and the screws of the coilpacks, if the number isn't 0 or 1 then you probably want to do this simple and cheap fix.

Basically you need:-2 ft of wire loom, probably 3/8 ID or 1 size bigger...-some stranded wires, prefer same size/black color, 12 to 16 gauge should do. If you don't have it in a roll, buy like 10ft since it is so cheap anyways and you can use the extra on something else-wire stripper for the said gauge wire-1 ring connector big enough to accommodate the typical 12mm bolt on 240sx and the 4 wires combined.-soldering iron and some solder, any type is probably fine.

1) find a good spot on the firewall for grounding, look for any bolts you can remove. There should be a few right in the middle of the firewall.

2) Use the wire to measure the distance from the said bolt to each of the 4 coilpack mounting screw, then cut 4 pieces of wires in according to the rough measurement with a little extra wires to spare

3) you should have 4 unequal length wires, strip one end of each wire by about 2cm to expose the strand. Twist the strand with your hand and use the soldering iron to apply solder to all 4 exposed and twisted strand (this is to prevent splitting and to make the tip stronger) It is possible to use ring connector instead or other connector but I could not find the right size that is small enough.

4) secure the wires by each of the coil packs mounting bolts. Wrap the wires in wire loom and pull it toward the ground, cut the other ends of the 4 wires so it will be equal length. Strip to expose the strands, twist all 4 strand together and cramp it to the ring connector. Then mount it to the firewall.

5) You may want to secure the wire loom with zip ties and check the resistance again at 2000 setting. It should now read 0 or 1. You can also use 200 for better reading.

I noticed immediately that the funny idle I had is gone with this. Have not had the chance to drive the car yet since I am doing other stuff.

[AmoebAssassin]

Great idea, clean and simple in execution. I'll do this to my car once it warms up a bit outside.

[slow s13]

Im pretty shure the ground comes through the harness, with stock coils the piece that is screwed down is made of plastic so your just grounding the valve cover and not realy doing any good. On my engine I put an extra ground from the head to the firewall.

[ILikeMy240sx]

Do you buy any chance know the size of the screws for the coil packs?

As of now, I dont have any screws holding the coil pakcs to the valve cover... They are just press fit on there which probabaly isnt good...

[srpowered240sx]

Im pretty shure the ground comes through the harness, with stock coils the piece that is screwed down is made of plastic so your just grounding the valve cover and not realy doing any good. On my engine I put an extra ground from the head to the firewall.

i was under that impression too, considering the valve cover is made of aluminum (i think). there is a single black wire that comes out of my coil pack harness before it starts to split to individual coils, and it is grounded to the firewall already.

btw, any reason you didnt use ring terminals at the coilpack end of your ground harness? i think i might cut open a dead coil that i have to see if it really does ground through that hold down scew. good diy reguardless.

[Fenvy]

ring connector sounds like a good idea, but it does not work so well when you actually try to put it on. either the outer diameter is to large and hitting other stuff or the interior diameter is too small to accommodate the bolt.

To be honest, I do not know if it works or not. I did it based on 1) what someone else said, that coilpacks should be further grounded 2) there is a product to combat this (phase2's grounding plate)

I went back to search on Z ilvia/ fresh alloy and someone said it's not all rubber. I do not know because I am running spitfire coils right now and they are metal.

I tested it this morning at 200ohm setting and I got 1.2 to 0.8 with the grounding and about 35 without the grounding.

So what is the bottom line? The material can be had for about $5 to $10 which is nothing to you. If it really works, great, if not, at least you have improved the ground of the valve cover.

[Blown240sx]

Umm I dont see how this helps much. I mean yea it makes a better ground but the splitfires come with two grounds built in. Did you check the resistance on those two ground wires because those wires are the ones that ground the coil packs?