LS Ignition Coil Upgrade

[Gimpster]

Hey everyone, this will be a work in progress/diary DIY. I will keep editing this first post until conclusion. I typically do my big forum posts like this, so sorry. I HOPE to at least have the proof-of-concept running/idling the car 11/18/2017. That all just really depends on the time I have and if all of my parts arrive on-time.

Okay, so first off: I really like the BNR coil upgrade. That has to be one of the better packaged aftermarket coil upgrades I've seen... on any platform. Hats off to them, really.

That said, a.) I am a poor person, b.) I do my own tuning (HPT) and c.) I like to DIY in general anyway.

Disclaimer: If none of this makes sense to you, save your pennies and buy the BNR kit Also, you will need to own or have access to a tuning solution which will allow you to modify your spark dwell settings.

My goal is to have no more than $150 into this setup.

Parts Needed

Coils:

Besides having owned a lot of various LS powered things, I also own a Mazda Miata. It runs a standalone (MegaSquirt), and on that car I chose to use the GM D585 (AC Delco PN: 19005218) coils. These are all over the junkyards CHEAP, and a pretty hot coil. I typically snag them off early/mid 2000's truck and SUV's. I'm not saying these are THE BEST GM COILS, but it's light years ahead of most stuff and what comes on the Sonic. You are typically talking 40kV+ on the better models of LS coils.

One thing to know about the D585 is that its a semi-intelligent coil. It is known to fire when saturated > ~4.5-5 milliseconds dwell no matter what you tell it. This is more of an issue for the people making extreme (think 1000+) horsepower, and why it has fallen out of favor a bit.

You will need four of these. If you buy them at the yard, snip off the connector leads too.

I highly recommend genuine/OEM coils. The Chinese junk (even AC Delco branded) have often proved to be unreliable or not perform. That goes for any LS coil really in my experience. This is what the D585 looks like:

Male ignition plug connector, pins, wire and wire seals:

I want my conversion harness to look OEM and professional, so I put in the work to track down the part number of the coil side plug, pins needed and wire seals. The harness plug is what mates with the stock engine harness coil pack plug, if that wasn't clear.

Harness Plug - Qty. 1 PN: 15359189
Pins - Qty. 7 (I recommend buying more!) PN: 54001845
Wire Seals - Qty. 7 PN: 15366021 OR 15366060, depending on what gauge of wire you use. More on that below.

15359189

54001845

15366021

15366060

I am using an assortment of 20AWG TXL wire to complete the project. I looked at the car side of the harness, and it seemed to be about what they are using. If I need to upgrade sizes later (would only be on the +12V and negative if I did) I can. I just have piles of this stuff around from building harnesses for other stuff. Since I am using 20AWG, the white seals (15366021) work fine. If I was going larger, I would need to use the blue (15366060) seals.

You can get a cheap assortment of TXL wire from people like this: https://www.amazon.com/gp/product/B01FJ21RDM

You will also need the four pigtails mentioned under the coils section. If you can't get them from the junkyard, look on eBay... you will see a zillion different LS coil harnesses for like $17-20 dollars you could buy and cannibalize for this project. I'm sure the coil harness plugs can be sourced with wiring as well.

Coil Bracket:

I will be using ICT Billet PN: 551562 D585 coil relocation bracket. I am unsure yet if I will mount the coils to the valve cover, the firewall, or some other place. It actually comes with two brackets, so you can make another set for a friend or .. whatever.

https://www.amazon.com/dp/B01M4LYET8

It should go without saying you can make your own bracket, or re-purpose a bracket off an LS motor (they bolt to the valve cover) if you are very budget minded. I almost did the latter, since I have a ton of them in a box... but wanted something a little nicer looking

Here is what my ICT Billet brackets look like with the coils assembled on the bench:

Spark Plug Wires:

I will just be using LS powered truck straight boot wires. I have a ton of old ones laying around my garage, and will provide some part numbers at a later date for everyone.

Example:

Wiring Diagrams

Ignition connector pinout (NOTE: this is as viewed from the engine harness!):

Ignition coil pinout:

Full wiring diagram to coils:

 

[Gimpster]

Wiring It Up

As stated earlier, I want an OEM as possible look. I did the hard work for you, and tracked down all the GM part numbers for the plugs, pins and such. I used to own a ton of GM specific crimping tools, but sold them all off a while back (oops!). So I'm having to build these the "hard way" a bit. Most notably, I don't have any of the crimping or pushing tools for the wire seals anymore. That's OK though, its easy enough to work around that on such a small project.

Please note that, except for +12V (red) and chassis ground (black), the other wire colors I picked at random.

At the minimum, you will need a decent pin crimper, this is what I'm using:

You will strip back about 1/4" off your wire, and insert it into the male pin and crimp it down like this:

Then, slide up one of your wire seals. You will gently crimp around it in a circle, it must be tight enough to fit inside the connector body:

Slide the completed crimped and sealed end into the connector body. Push it in as far as you can with your fingers. Since I don't have the official GM push tools anymore, I pulled on the pin gently with my small needle nose pliers to seat it into the connector body:

Keep doing this six more times, and you'll have something that looks like this:

Once you are happy with how everything is seated, you can snap on the seal retainer (should have come with the connector!):

Now you have a pile of wire to your connector, and we can move to sizing it to the right length on the car.

I took the assembled coil pack out to the car, and laid it about where it should go when I make the brackets. In my car, this meant about 16" of wire off the connector I assembled was required for a comfortable reach to the engine harness ignition plug.

To make things easier, I bought an LS truck style ignition sub harness like this (NOTE, you can get these cheaper if you look around on eBay):

https://www.amazon.com/dp/B01N9VI9LZ

I then cut the big connector off, and matched up the wiring diagram provided to my plug. Since this harness is straight outta China, none of the colors made any sense even to an LS harness. Just use the diagrams provided, and I assure you it will work out. I am assuming here you can read a wiring diagram if not, stop now. ALSO, note that cylinder #1 is the side of the engine closest to the serpentine belt, and #4 is closest to the transmission. Solder all connections and heat shrink them up.

Coil Bracket Mounting

This is one of those thing you will have to do according to your skills, and what materials are available to you. I kinda whipped this up quick in a couple hours with hardware store steel and my MIG welder. I do not claim to be a master fabricator, so laugh away.

What I did was re-use the stock coil mounting bosses on the top of the cylinder head. As you can see, I just used some flat steel to hold my coil bracket. I then welded on a couple ears diagonally to ensure they would clear the nearby spark plug wells. Then to those ears, I welded on some tube steel to the length I wanted for the bolts to go through to the head.

At first, I was going to make some elaborate rear bracket to use the fuel rail mounting bolts. After looking at it more, this seemed really unnecessary. So I used some rubber standoffs and the weight of the coil brackets + coils allow it to sit firmly over the intake cam area of the cam cover. I tweaked the tubes+arms back a little to make it act like a spring, and its pretty rock solid.

The pictures kind of explain the rest, but I countersunk the coil bracket holes so the hardware wouldn't rub against the cam cover.

The way I made this, I should be able to utilize a couple commercially available coil covers (with modifications) and I think it'll look okay.

My plan is to either paint or powder coat my mount gloss black, I am not sure yet.

 

[Gimpster]

Spark Dwell Settings

I have attached to this post a zip file, and inside this zip file is an Excel. In HP Tuners, navigate to Engine -> Spark -> Dwell. You will see four tables under this section, and a tab in the Excel corresponds to each.

Just paste in these values, and you should be good to go on the D585 coils. Note that I pasted in the axis of those tables too, so verify that and/or paste the entirety.

Conclusion

Will put how I like the conversion here once I get some miles on it.

 

[MaD]

Very cool write up, definitely need more pics [emoji41] [emoji106]

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[ScarabEpic22]

You're the man, I have extra coils (actually these same ones) lying around from some LS engines that I'm going to use on my Sonic. I was having a hard time finding the connector part numbers, so THANK YOU! Figure I'm just going to hack up the existing DDM coil cover I have to fit the new wires.

I'd suggest using the dwell settings from a 2011-2016 Express Van or a HD truck with the 6L. I imagine the 4.8 would work as well, likely same coils. These engines run the same E78 as the 1.4T, so the table axes are identical.

 

[Gimpster]

Lol... I admit to being a bit picture heavy. At least I host them on Amazon. Stupid Photobucket has basically broken almost every forum I use and removed value :\

Small update... parts showed up waaaay faster than I expected. Everything I needed to physically do this conversion is in hand now.

I assembled the coil brackets + packs. You can also see the pre-fab LS coil plug harness I'm going to adapt and make this all look pretty. These are what a stock LS motor would use, they have those little sub-harnesses off the main engine harness. I'm basically going to snip off the large LS harness plug, and solder the length + the Sonic 7 pin plug I assembled to it. I got this harness for like $19 on eBay, ... really nice deal.

As I go through that I'll update the DIY itself.

At least you can see where I'm going with it a little more clearly.

So next I'll work on finishing the harness up, and hopefully we'll see this guy running the car soon as a test. Then I will need to figure out how I want to mount the coils+bracket. Pretty sure I'm going to go above the spark plugs... there is a TON of room between the top of the valve cover and the hood. I'm just not sure how I want to secure it to the valve cover yet. This isn't light by any means...

Very cool write up, definitely need more pics [emoji41] [emoji106]

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[MaD]

Looks good! Need them installed with pics!! [emoji16] [emoji106]

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[Gimpster]

No problem. Digging through the Delphi catalog to find those was a PITA.

Should anyone ever need it, the HARNESS side connector PN is: 15317367

I'll take a look at those trucks you suggested and see what the tables look like. I knew there were some trucks that used the E78, I just hadn't had a chance to lockdown which to snag yet... so thank you!

You're the man, I have extra coils (actually these same ones) lying around from some LS engines that I'm going to use on my Sonic. I was having a hard time finding the connector part numbers, so THANK YOU! Figure I'm just going to hack up the existing coil cover I have to fit the new wires.

I'd suggest using the dwell settings from a 2011-2016 Express Van or a HD truck with the 6L. I imagine the 4.8 would work as well, likely same coils. These engines run the same E78 as the 1.4T, so the table axes are identical.

 

[ScarabEpic22]

No problem. Digging through the Delphi catalog to find those was a PITA.

Should anyone ever need it, the HARNESS side connector PN is: 15317367

I'll take a look at those trucks you suggested and see what the tables look like. I knew there were some trucks that used the E78, I just hadn't had a chance to lockdown which to snag yet... so thank you!

I have a file in both EFILive and HPTuners format, if you want it just shoot me a PM and I'll send them over.

I saw the harnesses and was like bingo, exactly what I'm going to use to get all the connectors (and assembled to boot!). I have a full harness off a spare engine, but I'd rather leave it intact and for less than $50 it's a no-brainer to keep it intact if I need it for a swap later on.

 

[Gimpster]

Cool, I'll shoot you a PM here now.

Yeah I didn't want to cut up any of my stuff either. I'm kinda protective of my Gen3/4 parts stash

Maybe you can find it even cheaper, but this is the eBay seller I got mine from for $19 shipped:

https://www.ebay.com/itm/LS2-LS7-LQ...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

I have a file in both EFILive and HPTuners format, if you want it just shoot me a PM and I'll send them over.

I saw the harnesses and was like bingo, exactly what I'm going to use to get all the connectors (and assembled to boot!). I have a full harness off a spare engine, but I'd rather leave it intact and for less than $50 it's a no-brainer to keep it intact if I need it for a swap later on.

 

[Tormach]

Could you find a way to make a bracket that utilizes the 2 existing torqs bolts that secure the oem coil pack and then mount the ls bracket to it. Or one of the hoist brackets.

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[Big Turbo Sonic]

A tuning DIY to pair with this thread would be awesome!

 

[Blue Moon Sonic]

This write up is amazing. Hats off to you for doing this. I will agree with tormach. Find a way to utilize the oem fastener locations. That'll give that plug and play feel to the kit.

 

[Gimpster]

Finished soldering up the harness, hoping to try idling it with the pack just hanging loose as a test tomorrow night. Updated the appropriate sections of the DIY with more diagrams and pics/info. I ran out of loom, so I'll get more tomorrow and finish that up 100%.

I'm going to do my best to use the OEM coil pack mounting locations. I agree with you guys it would be best to have it use those.

I am inclined to brace the back using the fuel rail mounting bolts as well due to the weight. I'm not sure yet... hope to get that more flushed out not this weekend, but the one after. I have some family obligations that will keep me out of the garage a bit. Basically I plan on making a "table" for this coil bracket to bolt to is all. It has those down facing holes on the outer coil brackets that should make it cake.

I will likely use steel for my brackets and have them powder coated. I own a TIG, but I am kinda crap @ welding aluminum so I tend to stick to steel since I'm pretty good at that. Skill I really need to get better at, but its all about having time!!

Here is about where I hope to have them. Plenty of hood clearance to go up with the brackets if you reference it against the intake heat shield.

 

[Tormach]

I like it, def going to look awesome. Very nice DIY write up.

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[Gimpster]

Well, tonight I hooked it all up and uploaded a tune with the right dwell settings. Turned the key with a smug grin, and............. no start! Took a spark plug I had laying around ... no spark.

I checked all my wiring, and it appears my Chinese LS ignition harness is wired backwards at the coil. Its mirror flipped, so I didn't think much of it when I was soldering it up. In short, it is wired up like an original LS1 coil would be. Hoping I didn't fry this set of D585's, and let that be a lesson to all of you to not trust everything you buy for $17

I put it on the bench next to a legit LS2 harness, and.. yah...

So, I will re-pin them at the connectors and try again when I get a chance.

 

[Gimpster]

It runs!

https://youtu.be/wOVNXtMN45w

---

Now to the issue I mentioned in the video. It appears the pins I chose for the harness connector are too small, and I need to purchase the next size up. I had an issue when I hooked it up of no spark on cyl #1. I scoped things out, and the ignition trigger was not making contact. I bent the pin up slightly so it would for sure contact the female side, and voila it worked.... hope that made sense.

Off the bat, I can tell you (as I'm sure BNR LS7 kit owners will agree) the car idles a lot better. My car almost always had a slight miss on start, and it did not with these coils.

So:

1.) I need to figure out a better pin, I will update the parts section when I figure that out. EDIT: Going to give these a try https://www.ebay.com/itm/112328252978 I noticed the stock coil pack (at least mine) are gold plated which makes them just slightly larger. Hoping these will be a little more snug.

2.) I need to start figuring out brackets ASAP.

 

[Tormach]

Sweet!!! Nicely done dude.

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[Italianjoe1]

In for this. I have HPT so the BNR situation was not an option for me either, but the LS coils are great.

 

[BNRacing]

BNR tune is no longer required for our kit. It was never to stop you guys from using it, it was to stop people from buying it and using trifecta or something and it not working right and now we've got a paypal dispute on our hands. As long as you check the box that you won't try to return it and you know you have to do some tuning for it, you can buy it.