i got a set of 4 LS2 truck coils with the bracket and harness with pigtail. from what ive read online from the RB guys its fairly simple to wire up. my issue is i have a new wiring specialties harness that i dont want to cut up. i do have 2 spare RWD CA harnesses. my question is. do i need to remove the ignitor and make a bypass plug and is the wiring the same as the RB guys. i am running nistune so essentially the stock ecu no standalone. hopefully someone has done this and has some input. thanks in advance guys.

Nobody here has done it, at least if they have, they've never posted about it. I just found this thread;
ls2-truck-coil-swap-t478565.html
From what I'm seeing there, you have to remove the stock coils and the stock ignition amplifier (Ignitor). These coils have the ignitor built into them. I see one huge issue with these swaps people are doing. The dwell is controlled by the ECU on these setups. The chance that the dwell is set properly for these coils is slim-to-none. Will it work? Probably. Could you be damaging the coils or not getting the spark strength the coils are capable of? Absolutely.

Nevermind, I think I might be wrong. I'm not 100% sure, but those coils with the heat sinks might have built in it ignition control modules. What this means is that the dwell portion of the ECU isn't needed to control the saturation of the coils. The coils keep themselves charged, but not overcharged. This is why nobody has had any issues with them overheating or not having enough spark energy. They're actually a pretty good coil. I'm not sure how the price compares, but you might look at these;
http://www.aemelectronics.com/high-outp ... -coil-1240

Plus they come with plugs and a wiring diagram and output waaaaayyy more spark energy and duration than the LS2 truck coils.

float_6969 wrote:Nevermind, I think I might be wrong. I'm not 100% sure, but those coils with the heat sinks might have built in it ignition control modules. What this means is that the dwell portion of the ECU isn't needed to control the saturation of the coils. The coils keep themselves charged, but not overcharged. This is why nobody has had any issues with them overheating or not having enough spark energy. They're actually a pretty good coil. I'm not sure how the price compares, but you might look at these;
http://www.aemelectronics.com/high-outp ... -coil-1240

Plus they come with plugs and a wiring diagram and output waaaaayyy more spark energy and duration than the LS2 truck coils.

I've researched these coils quite a lot. (If you can call 160+ hours googling and forums searching "research". So from this point on, everything is second-thirdhand account, but I think I've managed to separate the wheat from the chaff.)

They are very good, according to the LSx community, and you would have to pay much more to get even just slightly better ones. At least in case you have OEM stock, or ACDelco ones, as every other manufacturer is of inferior quality. (They were bench-tested side by side on one of the sites I've looked).

Dwell is still controlled by the ECU, only the ignition amplifier / igniter / power transistor part is built into them, just like float said. There is a slight problem, though. They have some "smart" built into them, which is the overdwell protection. If they are charged (or more accurately, fluxed) for too long, to protect themselves from overheating, they discharge by themselves, before the ECU gives the signal to do so. This results in an uncontrolled timing advance. Needless to say, that's something you really don't want. But the good news is, if you don't set too high dwell values in the ECU, you won't trigger this questionable defense mechanism. What people regard as too high dwell varies quite a lot, though. I will just go by the stock dwell table of an LS2, when I install mine (just google for it). (This behaviour was properly bench-tested by someone on a 944 board IIRC, it is not actually a time limit, but a primary current buildup limit, and how that translates into dwell time limit could vary on the application.)

I'll try to remember to post the sources for actual tests, and other credible info, I have them on another computer.

Don't forget to check and re-set your base timing the PROPER way, after you've installed them.

Yea, he's right about still needing a dwell setting. I was doing some more reading last night and they do just replace the coils and the ignition amplifier.

ok awesome i have 6 of the ones with a heat sink on top and 8 of the ones without a heatsink. (the ones without came out of a 99 4.8l, heatsinks came out of an 03 suburban). i plan on using the heat sink ones. My next question would be is there a patch cable or harness that i can make or source from somewhere to delete the ignitor without cutting my harness at all there. i Know i probably never will but maybe ill one day want to go back to stock. in this case i would like all the factory connectors to still be there. i have 2 spare engine harnesses so ill cut up my old coil pack harness no problem. lastly. ive been reading that a 3ms dwell time is optimum and the choice of many. my main concern is the ignitor plug wiring staying factory without cutting. ill wire in a constant power off a relay to power the coils and then wiring from there will be super easy.

http://forums.rennlist.com/rennforums/9 ... ystem.html
A proper test of the round, heatsinked D585 "LS2 truck" coils, with the overdwell, or actually overcurrent protection. Page 9, but the whole thing's a good read, if would like to understand more, which I always advocate.

cadet18 wrote:ok awesome i have 6 of the ones with a heat sink on top and 8 of the ones without a heatsink. (the ones without came out of a 99 4.8l, heatsinks came out of an 03 suburban). i plan on using the heat sink ones. My next question would be is there a patch cable or harness that i can make or source from somewhere to delete the ignitor without cutting my harness at all there. i Know i probably never will but maybe ill one day want to go back to stock. in this case i would like all the factory connectors to still be there. i have 2 spare engine harnesses so ill cut up my old coil pack harness no problem. lastly. ive been reading that a 3ms dwell time is optimum and the choice of many. my main concern is the ignitor plug wiring staying factory without cutting. ill wire in a constant power off a relay to power the coils and then wiring from there will be super easy.

Definitely no readily-made igniter delete cables. You have to do it yourself, but it's really just a matter of looking at the FSM to see which pin's which, then crimp some connectors to wires, and replacing the ignitor with them. Or go straight to the coils from the ECU->igniter terminal.
Like this guy.
http://forum.nistune.com/viewtopic.php?f=12&t=1715

Re-check your base timing afterwards for peace of mind. Should be much easier with the plug wires exposed.

OK. Really dumb question, but some of this is over my head. Could I just use the stock CA tune with this or would I have to tune for it?

Ideally, you would tune for it, but I think it will probably work with the stock tune. The issue will likely be that the dwell will be too low on the stock tune as the stock coils probably charge much faster than these, so the dwell will be too low to get these coils to saturate.

I have these wired up now and have tried 8 different coil packs to see if the packs were possibly bad. i bypassed the ignitor by matching colors and connecting them together(red/white to red/white...so on). so now i should be getting a 5v signal from the ecu instead of a 12v signal. i did not use the ground wire on the 6 pin connector from the ignitor. that ground wire runs into the bundle which bolts to the side of the intake(the 2 10mm bolts on the back right of the intake. i also wired the ca coil pack harness into the gm harness connector using the FSM. i have tried coil on plug with springs/boots, and plug wires with no change. i can see 12v switched in the gm harness when i switch the key on. i did not connect anything to the small black wire on the coil pack harness as it doesnt go to anything. when i try to start the car it turns over fine but wont start. it will either backfire loudly after a while cranking on it from the exhaust or it will make this sound like a dog barking out of the exhaust (like a single dog bark). i have gone over the wiring 3 times now and i dont believe i have missed anything but maybe i have. hopefully its something i have looked over and will be an easy fix. HELP ME OUT HERE GUYS!!! when i switch back to the stock ignitor and coil packs and ignitor the car starts right up and runs perfect.

Just to clear something up, by "coilpack harness", do you mean this particular piece of the stock wiring?

And by "small black wire" do you mean the one connected to the black probe on the right?

Or do you mean the harness that's supplying the above "sub-harness"(?)? The one with the wire-loop connector?

Did you try the heatsinked or the non-heatsinked coils? Or both?

Also, just making sure, did you check the GM harness wire colors that actually go into the coils themselves, or did you go by a pinout picture? Because the wire color orders are different, depending on whether it's a left or right side bracket harness. http://www.ka-t.org/forums/viewtopic.ph ... 62#p353562

i took the wire harness pictured above and cut it right behind the black wire touching the multimeter. that wire no longer exists in the ls harness i built the loop wire however does but it isnt connected to anything i assume that wire is for using a timing light. i spliced the engine harness side of the wiring pictured above and soldered it to the ls factory harness and made sure to wire the colors to the correct coilpack. i have checked this over 3 times. interesting article on the KA situation. never would have thought that but it doesnt interfere with how mine is wired. thanks for the input. im thinking maybe my power wire isnt good enough. i am using the factory power source to power all 4 coilpacks. maybe it isnt string enough? idk... and i tried bothe heatsinked and non heatsinked. thanks for the help!!!!

cadet18 wrote:i took the wire harness pictured above and cut it right behind the black wire touching the multimeter. that wire no longer exists in the ls harness i built the loop wire however does but it isnt connected to anything i assume that wire is for using a timing light. i spliced the engine harness side of the wiring pictured above and soldered it to the ls factory harness and made sure to wire the colors to the correct coilpack. i have checked this over 3 times. interesting article on the KA situation. never would have thought that but it doesnt interfere with how mine is wired. thanks for the input. im thinking maybe my power wire isnt good enough. i am using the factory power source to power all 4 coilpacks. maybe it isnt string enough? idk... and i tried bothe heatsinked and non heatsinked. thanks for the help!!!!

(NB: The small loop is not for a timing light, it's an RPM pickup for diagnostic purposes. It is actually the #1 coil primary voltage wire, elongated a bit, and hanging out at the connector.)

For future reference, let's call the above pictured harness piece the stock coilpack subharness, and the other side of it, the one that connects it to the igniter, the igniter harness.

Power should be strong enough to produce at least a startup and idle, IMO.

I've read and re-read, but what I don't yet get, is, where did you connect the ground for the GM subharness? Did you have a ground in your igniter harness? Because in my Euro igniter harness connector there is no ground, only a +12V, and the 4 cylinder primaries. My stock coilpack subharness gets its ground from the small black wire bolted to the holding plate under the stock coils. (Not connected in the pic above, because it hsa corroded off said bolt.)

And I really hope the Euro stuff I have is the same as the JDM, otherwise I'm misleading you.

I'm trying to make head or tails of the ignition wiring diagram in the FSM. I don't understand it quite yet, but I can't say I'm entirely convinced that the wire colors belong to the same cylinders on the two sides of the igniter module. It would be very stupid if they weren't, but still.

Did you try checking continuity all the way from the ECU directly to the GM coil connectors? I'd give it a try.

Lacking a continuity checker, you could try removing all of your plugs, disconnecting all coils, remove all of the ingiter delete wires. Pick and connect one coil and plug, and put in ONE igniter delete wire at a time, and see if the plug sparks with one of them.

They're not the same. The Euro harness has the ignitor in the chassis wiring. In the JDM harness, the ignitor is in the engine harness.

That being said, the wiring shouldn't be different.

First of all, if you bypass the ignitor, you HAVE to use the heatsink style coils. If you use the non-heatsink coils, you HAVE to use the stock ignitor. It might be wise to use the non-heatsink coils and the stock ignitor to start with so that you're only making one modification at a time.

After looking at both wiring diagrams, there has to be a ground issue. The stock CA coils secondary windings grounds through the harness itself, so there is no ground at the plug. This is the black wire that bolts to the plate that blownhemi is talking about. Have you tried removing the plug from a coil itself and making sure the black wire on the GM harness has continuity to ground? If you didn't connect that wire to ground inside the GM sub-harness, just like Nissan did, you probably don't have a ground and the coils can't fire.

Secondly, I think there is another issue. Do the GM coils have 4 wires at the coil itself, or 3? I'd be willing to bet it's different between the heatsink style coils and the non-heatsink style coils, where the heatsink coils have 4 wires at the coil and the non-heatsink has 3.

The issue is that the the heat sink style coils basically need two grounds. The wire GM calls ground is the high voltage wiring for the secondary windings for the spark plugs. This needs to ground to the head. The second ground, GM calls low reference. This is the ground for the built in ignitor. This HAS to ground in a COMPLETELY different place, ideally the intake manifold, just like the stock ignitor did.

Let me know if the non-heat sink coils have 3 wires going to them, and I can give you an easy way to wire it up. If that works, then I can then move you forward to removing the stock ignitor and using the heat sink coils with 4 wires.

float_6969 wrote: First of all, if you bypass the ignitor, you HAVE to use the heatsink style coils. If you use the non-heatsink coils, you HAVE to use the stock ignitor. It might be wise to use the non-heatsink coils and the stock ignitor to start with so that you're only making one modification at a time.

The distinction is not that simple, lack or presence of a heatsink in itself is not indicative of a built-in igniter. Most of the LSx coils don't have a heatsink, but have a built-in igniter.

float_6969 wrote: Secondly, I think there is another issue. Do the GM coils have 4 wires at the coil itself, or 3? I'd be willing to bet it's different between the heatsink style coils and the non-heatsink style coils, where the heatsink coils have 4 wires at the coil and the non-heatsink has 3.

That's where your right. Whether it has 3 or 4 four pins is much more telling than the heatsink. But up until now, I've only heard of LSx coils with 4 pins and built-in igniters.

Could you maybe post pictures of your coils, one of each kind? I'm curious which kind of the non-heatsinked LS coils you have.

That's good to know. I thought all of the non-heatsink coils lacked a built-in ignitor.

sorry its been awhile before i had a chance to reply guys ive been busy selling my house and getting ready for a PCS. I have ended up getting the car running. I had the ignitor bpass wired wrong. it turns out that the colors on the wiring dont correspond to each other at all on each end of the ignitor. i changed it to reflect the 1992 Q45 service manual ( they have the same ignitor). now it runs beautifully. i have been able to open my gap from .022 to .037 with no spark blowout running E85. it has a much smoother idle and pulls through the rev range better than ever. i also made these coil near plug packs to be coil on plug. i used half of a ford expedition 4.6 coil pack spring and the factory CA coil boot. Works like a charm. if anyone else is interested enough in this i could do a write up on this. i think it would be pretty beneficial to the community just seeing as the expensive alternatives that we have to stock coils (splitfire), as well as a cheap GM alternative that you can get in any local advance auto parts store. That being said if you guys show enough interest on here i can do a write up. I also have 8 non heatsink LS coil packs with brackets and harnesses if anyone is interested in doing this. Thanks again to everyone on here for being my go to forum for engine related questions! keep the CA community strong!!!

I don't actually perform the work, but I'm TOTALLY interested in a write up!

I would also be interested in reading a writeup.

See here
http://forum.nistune.com/viewtopic.php?f=12&t=2423

so ive finally gotten settled in at my new place in DE and was able to take some pictures of my ignitor bypass i made. i tried getting the coil harness picture but i need to remove 2 grounds and dont have any tools here as i live in an apt. now instead of my old house. anyways hope this helps to clear up some of the confusion from my lengthy write up on here with some pictures. when i get a chance ill try and put up my coil pack harness pictures.