LS2 coil installation issue - please help

[judasentinel]

I have not been able to get a straight answer to the question I have, possibly because there are two versions to the installtion - one with a relay with 12V directly given to each coil from the battery, and the other without a relay, with the 12V coming in from the stock coil power plug.

I am going the relay route, and have the following setup:

12V coming in from the coil power plug (2 pin connector) to the relay to act as a trigger/switch
The ground from the same pin connector goes to the other side of the relay to complete the circuit
12V coming in directly from the battery into pin 87 of the relay
12V going to the coils from pin 30 on the relay

With me so far?

Now this is where I am stuck - each coil has 2 grounds - one is called a signal ground and the other is a hard ground. I can combine all 6 hard ground wires and connect them to the chassis, and this will take care of one ground. Where do I connect the signal ground? Could it still be mounted to another location on the chassis or anywhere I want? Or does it have to be connected back to the relay? The relay already has one ground connected to the 2 pin connector ground, so I am really confused about the coil signal ground as to where it goes.

Can someone please help me? I have made the harness and it is ready to go in. Just wondering where to ground the two different grounds on each coil.

Thank you in advance....

[Bruizer]

ground them on the ground point. because ground is ground

[judasentinel]

ground them on the ground point. because ground is ground

The question remains though, how to find the really grounded ground to ground the two grounds

In all seriousness, is it ok to connect the coil ground to the negative terminal of the battery and the second ground to somewhere on the engine block?

[AL91GTR]

I'll double check mine later but I believe I grounded the common ground back to the two pin connector (one is switched power, the other is ground). I tied two coil grounds together and grounded in three spots using the little screws that used to hold the original harness metal clips.

Come by and take a look. It's all easily visible ... I'll be home tonight or on the weekend. nine oh five six five one one zero four two

[judasentinel]

Understood, Al....so if i understand correctly, the 2 pin connector's ground should connect to the combined coil grounds (6)? And what about the ground for the relay? The 12V signal from the 2 pin goes to the relay, and the other side on the relay needs to be grounded too...I was thinking that should go to the 2 pin connector ground, or should I just connect it to the chassis?

Which of the 2 grounds is the common one, when looking at the coil itself? The right most or the second one from the right?

Is it ok to connect individual coil grounds to the screws for the stock coils?

[AL91GTR]

Here's my harness. No free time, so I purchased from ToroGTS on here ... good quality and fit perfectly. Highly recommended seller.

You can see the individual coil ground for each coil. The separate black wire at each plug. I took two of these and grounded to three places because it fit well this way and re-used factory bolts and holes. If you want to ground all 6 together or each individually I don't think it makes any difference at all. Bruizer summed it up pretty well. the 'main' common ground I tied into the 2 pin so that I have plugs in case I need to pull the harness it makes it easier. The 6 signal wires I tied into where I cut out the factory igniter and installed a 6-pin connector for the same reason

[judasentinel]

SUCCESS!!!

I just installed everything and fired her up. No issues whatsoever. I joined the main grounds (for all 6 coils) together and connected to the 2 pin connector, while I divided up the individual coil signal grounds to two different locations on the chassis - one in one of holes like you did, and the other near the right fender. There is still some cleaning left to do in terms of wiring and taping it all up, but she runs.

I was running 0.8mm gap with stock coils. It seems that the car is running richer than before....should I increase the gap to 1.1mm now to alleviate that? It is hard to tell if it is running any better, but I have noticed that the cold start hesitation at 2000-3000 rpm is gone.

I also feel that the length of the ignition wires is a bit too much, so I will be cutting them short. Finally, I have to figure out how to bolt up the bracket I have made from a piece of plastic - Rona wouldnt sell me a piece of aluminium smaller than 3 feet, and I dont have a metal cutter. For now, she runs, and I am happy.

And I have you (Al), Shane, Anton (tryingtobebest), and others with similar setups, AND Bruizer to thank, not to mention my wife, who came up with a creative solution to design the bracket and install the coils on it. Thank you, thank you, thank you all.

And Al, BTW, I am also in the 40+ club.....

[Shane_Sawatzki]

glad you got it! Im a bit late in on this but yah, I ran all 6 signal grounds to the existing signal ground in the harness, I ran all 6 main coil grounds to chassis ground, as well as the Relay to chassis ground !

good work ! Pics of this bracket you fab'd would be sweet !

[judasentinel]

Well, for the life of me, I couldnt find a piece of metal cut to the right size, i.e., around 20 inches long. Rona refused to cut it for me, and I didnt go to the Ho Depot in the next town over. I had a long piece of plastic kicking around, which is the right length, but it is around 5 inches wide. I redcued the width to around 3 inches, and am in the process of finding a suitable place to bolt it to.

On my R33, the only spot I can think of is to somehow drill holes into the plastic cover on the injector harness, or somehow find a way to pass the allen bolts holding it down, through my bracket first and then tightening them. Not sure what else I can do. I know Al and some others have made brackets that sit in the valve cover valley, while others have fabricated metal strips to be bolted on top of the fuel rail with brackets. That option requires tools and space that I do not have.

I am still debating if I can use that plastic bracket in the valve cover valley without melting it. The plastic is thick, but it is plastic nonetheless. If I can find a piece of aluminium somewhere to drill holes into, I will use that.

The engine bay is a bird's nest right now, what with all the wiring. I have yet to clean up the harness, but hopefully soon. And then perhaps I can post up pics of what I did.

[steveo1502]

I bought this aluminum at Canadian tire , like 10 bucks



Welded a little bracket to bolt it ...but instead of weld you could bolt it

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[judasentinel]

Looks good, Steve....the only issue is that no Canadian Tire in Niagara region has a piece of aluminium that size. They only have 3-4 ft long pieces, and I dont have the tools to cut it. Otherwise, it would be done and over with by now. Its quite weird. IU spent 3 hours today, looking for a spark plug terminal for the ignition wire I have. 3 Canadian Tire, 2 Parts Sources, and one NAPA later, no luck. None of them even knew that the ignition coil terminals are sold separately. They only had one answer - "we dont fix ignition coils and dont sell replacement parts. we just tell people to buy a new set"....I mean ri-fricking-diculous!!! Auto zone right across the border is selling these for $0.69 a piece....and we have to spend over $50 to get a car going just because a terminal is broken?

If I had a way to cut the aluminium, I would make the bracket just like you, Steve. My only choice right now is to use that piece of plastic and somehow find a way to bolt it to the top of the plastic cover on the injector harness.

[Bruizer]

I remember my split fires were bolt right on, no messing about. lasted years!

[steveo1502]

Lol ..... really ? How many kms in these years ? Just buggin ya bruiser , you always bash on people's **** but can never drive your car... it's no wonder you hate it .... It's the sort difference for me , split fires are like 500, I paid 40 bucks ,and maybe 10 for the bracket lol

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[curtisgoodman]

dont listen to him Bruizer lol... i got more expensive brand new stock coils when i rebuilt in 2009... still running strong at high psi and water meth... splits are good for the same amount of abuse im sure...

[judasentinel]

I was able to source out a mildly pliable piece of aluminium, bent the corners on it, drilled holes, bolted it on to the plastic cover on the injector harness, and installed the coils on top of it. Ran the newly made harness that shames a bird's nest, to the 12V and ground on chassis and battery, and it runs good now.

I will take a couple of pictures of the whole mess. Now the main challenge is to somehow nicely tuck away all the wires and turn it into a nice looking harness.

Thank you all, for helping me through this....