How to run LS coils MSPNP

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TrackStarGT
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How to run LS coils MSPNP

Post by TrackStarGT » Sun Aug 10, 2014 9:03 am

This may be a very specific thread, however it will be usful to many KA-T-ers that are presented with a similar situation. Though the "How to run LS1 coils" thread is very thorough, there are a few points that one might run into. So, the purpose of this thread is to compile good, specific, thorough information to help make the implimentation of LS coils, or any other wasted spark distributorless system, easier to install. I will recap the LS1 thread in order to make this a one stop shop for information instead of outsourcing and linking threads.

Cost of project: I did my install for ~$110 , got D585 coils still mounted to bracket and harness still attached for $55 shipped, 7 pin harness connector that connects to the coil harness(would be attached to vehicle side) $18, wire and fabrication materials ~$20
40 amp relay ~$10

Preparation and choice of phyical location for installation in the engine bay, firstly these coils are obviously designed for a different make/model/engine, and are not suited for direct bolt on installation anywhere in the 240sx engine bay. A mounting bracket of some sort will need to be purchased or fabricated. I will present a few examples in accompanying photos. Location is another important decision to make, there are roughly 3 different places to feasibly mount the coils, all of which have pros and cons.
1.Top of valve cover: this would seem to be the natural choice in location, however it presents some heavy cons: difficulty of bracket fabrication and physical installation, custom plug wires will need to be made or purchased, there is possible hood clearance issues, extra step created to remove valve cover: Pros are asthetics(they just look bas ass there), short plug wires(best conduction senario) im sure there are others.
2.Fire wall: This seems like a good option: Pros are, easier to create functional bracket and mount to, if mounted on passanger side of firewall, isolation from heat, possibly a shorter wiring harness. Cons: Heat could be a problem if not accounted for prior to location choice, potentially longer plug wires, hard to reach location.
3.Front valve cover: This seems like the least likely viable option, but present some good pros: ease of install and bracket fabrication, potentially cooler part of the engine bay, easy reach for service, average to somewhat short length plug wires. Cons: may not be as sturdy structurally(depends on quality of fabrication), not as asthetically pleasing, may make servicing front of engine more difficult adding a step for removal.

Now of course there may be other viable options for mounting, these are just most common, please post if you have photos of others.

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Plug Wires: Depending on choice of locations, it is an option to use current/stock plug wires. The elbow end that once plugged into the distributor can plug into the individual coils with little to no modification. The contact pin in the LS coils is about 1mm smaller in diameter than the contact pins in the stock distributor, with a needle nose plyers the contacts in the elbow boots can be "crushed" making them smaller in diameter, I have tested this and they hold well. If aftermarket wires are to be used then just take into consideration that stock wires do work.

Wire Configuration: I painted up a little schematic that is easy to understand and uses actual wire colors of GM harness for the LS coils. Please note that you need to clarify what LS coils you have, LS1s are reversed from LS2s as far as the harness connector at the coil. Important NOTE: please disconnect two pin connector that powers the stock single coil. There are two conncetors at the distributor, a 6 pin and a 2 pin, the 2 pin connector is the 12+ supply that powers the coil. Also please see IMPORTANT NOTE at bottom regarding 6 pin connector.

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make sure that you get the corresponding connector for the correct side of the vehicle the coils/bracket/harness were taken from

Simple Explaination of Wasted Spark systems: In wasted spark setups there is technically a "wasted" spark because 2 of the 4 coils fire at the same time while only one of them is actually on the compression stroke. This is why the 4 different signal wires coming from the coils eventually turn into two wires before they return to the ECU. Coils 1 and 4 make up Spark A bank, and coils 2 and 3 make up Spark B bank. So when coils are connected via plug wires in correct firing order: 1-3-4-2, and the ECU fires up, the signal sent is: A-B-A-B-A-B-A-B-A-B, which in turn, gives you 1-3-4-2-1-3-4-2-1-3-4-2.

Settings in TunerStudio: There are a few settings to change in turner studio when changing to a distriburtorless ignition system. First you want to change the "Single coil" setting to "wasted spark". Then you will need to change the dwell settings that are measured in milliseconds. 3.5ms is best for the LS2 coils. However, all settings should be confirmed in the MSEXTRA Manual.

Once settings are correct, you can test the out put of the coils, this is where you will see if everything is setup correctly of if you have any problems to address. Testing outputs is easy, just go to advanced settings all the way to the right top of the screen and choose test outputs. This will bring up a window, you will either be able to test injectors or spark and of course we want spark. Attach wires and and ground plugs to the motor Enable test mode and choose "coil 1" or "coil A" and start. You should now hear and see spark on your spark plugs 1 and 4, then choose "coil 2" or "Coil B" and hit start, and you should see the same spark from plugs 2 and 3.

VERY IMPORTANT Specific points regarding plug and play units. If you were once running a single coil, that means that you had power and signal for the stock coil. The MS will not like to send two 5v+ signals to two different coils. Which is esentially what will happen if the stock wiring harness is not modified. The first wire(White) on the 6 pin connector on the distributor is the signal that IGN1 will be sending the trigger signal through. When left connected your new coils 1 and 4 which are connected to Spark A out put on the ECU will have too low of voltage because it is fighting with the stock coil signal. This white wire needs to be CUT, yes CUT, once cut, the Spark A output signal will raise to its appropriate voltage to ignite coils. This can be confirmed two ways, Test mode succussfully getting spark, and using a multimeter and grounding at ECU and positive at the Spark A out put solder/crimp joint. You should see ~4.7v.
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Last edited by TrackStarGT on Tue Sep 02, 2014 11:43 pm, edited 3 times in total.
Daily Driver: 2010 Toyota Tundra CrewMax 5.7 TRD
Project and DD: 1995 Nissan 240sx Frankenstein

I live and breathe physics, mechanics, motorsports!!

My build thread viewtopic.php?f=40&t=60602

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Matt Cramer
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Re: Running LS coils MSPNP

Post by Matt Cramer » Thu Aug 28, 2014 6:29 am

Nice work.
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Nissan plug and play engine management now in stock!

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airman
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Re: How to run LS coils MSPNP

Post by airman » Mon Sep 01, 2014 10:25 pm

Made sticky :) This is a nice guide. Do you have a link to where you found your coils + harness connector, or did you find that used?
R.I.P. 1990 Red Hatch - DOHC 5 speed // CP 9:1 - Eagle Rods - Clevite - ARP // Holset HX35 - 20psi daily - MSPNP2
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TrackStarGT
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Re: How to run LS coils MSPNP

Post by TrackStarGT » Tue Sep 02, 2014 11:11 pm

that was used on ebay. Came off of a wrecked yukon denali. Thank you guys for the appreciation.
Daily Driver: 2010 Toyota Tundra CrewMax 5.7 TRD
Project and DD: 1995 Nissan 240sx Frankenstein

I live and breathe physics, mechanics, motorsports!!

My build thread viewtopic.php?f=40&t=60602

Missile
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Re: How to run LS coils MSPNP

Post by Missile » Wed Sep 02, 2015 12:34 pm

Can you run sequential firing cnp by using pins 2345 to signal each coil individually? S13 mspnp2

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Matt Cramer
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Re: How to run LS coils MSPNP

Post by Matt Cramer » Wed Sep 16, 2015 6:52 am

Missile wrote:Can you run sequential firing cnp by using pins 2345 to signal each coil individually? S13 mspnp2
Yes, but you'd give up swirl valve control (if you have a KA24E) and cooling fan control if running an electric fan.
Matt at DIYAutoTune.com - Megasquirt ECUs, fuel injectors, wideband O2 sensor systems, and more
Nissan plug and play engine management now in stock!

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