GM Ignition Module and Ignition Coil Swap 86-89 Samurai Part 1

[K Sparky]

GM Ignition Module and  Ignition Coil Swap for 1986-1989 Suzuki Samurai 1.3 L Carbureted Engine Models.

Parts require:
1) GM Ignition Module (LX301 Ignition Control Module) Amazon $10 (Note a Delphi DS10071 Ignition Control Module has been shown to be a better choice for high rpm use ( ThankYou for the input Paul))
2) GM Ignition Coil (UC15T Ignition Coil) Amazon $11
3) Wire (Preferably a paired white green combo like an old computer power cord) Free
4) Two GM ignition module connectors or four spade connectors Amazon module connectors $10 each, Spade Kit $9
5) Heat Sink for GM HEI Ignition Module Amazon $15
6) Solder $10
7) Heat Shrink Wrap Tubing Amazon Tube Kit $10
8 ) Zip Ties or Wire Ties (Single strand copper or bailing wire work) Harbor Freight $5
9) RTV Autozone $6
10) Bolts for Heat Sink / Ignition Module Mounting Any Hardware Store $1

Total cost if you don?t have anything on the list to start with and don?t use a computer heat sink instead of the GM heat sink is about $88 bucks. If you have most the stuff like shrink wrap, RTV, bolts, solder, spade connectors, and the like and all you need is the GM Ignition module and coil it will run you less then $25. The best part is that you can carry a back up ignition module with you in the glove box for $11 and swap it out on the trail easily.

Tools required for the job:
A) 17 mm socket and ratchet for rotating engine to top dead center
B) 12 mm socket and ratchet for removing and installing distributor
C) Soldering Iron
D) Needle Nose Pliers
E) Phillips Head Screwdriver
F) Standard Screwdriver
G) Heat Gun
H) Cordless Drill, 11/64 bit, 5/64 Bit, and a Step Bit or Debur Tool

This ignition module swap is largely based off of the Toyota to GM module swap popular in the 20R and 22R powered Toyota pickup trucks. The biggest difference in this is Suzuki and Toyota systems are that Suzuki has placed the ignition control module under the distributor while Toyota used an externally mounted ignition module. This made the GM ignition module a more obvious choice for the Toyota application because the hall effects sensor that serves as ignition pickup coil is similar in the GMapplication and the wiring is fairly straightforward. However, the ignition pickup coil under the distributor cap on the Suzuki is also a hall effects sensor and will trigger the GM ignition control module just as well. Some people have tried just wiring in a GM module just like the Toyota setup and it has not worked because the wires coming out of the Suzuki distributor are made to connect to the coil and the no off signal it sends won?t trigger the GM module. So, it takes a little more work prepare the wiring for the Suzuki application to work. The following writeup is how I got the GM Ignition system to work on a 1988 Suzuki Samurai. The Suzuki and GM wiring diagrams are shown below. After that I show the hybrid GM/Suzuki ignition wiring diagram.

Suzuki Ignition Wiring Diagram​

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GM HEI Ignition Wiring Diagram​

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Hybrid Suzuki GM HEI Ignition Wiring Diagram​

Procedure steps:

1) Remove positive battery terminal cable.

2) Rotate engine to top dead center cylinder one using 17 mm socket and ratchet.

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17mm on Crank Bolt ​

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Engine Marks @ TDC #1​

3) Remove distributor cap and make sure the engine is at top dead center and the rotor is pointing to cylinder one firing position.

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#1 Plug Wire Location

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Rotor in #1 TDC Position​

If the rotor is pointing to the #4 TDC location either rotate the crank 360 degrees or just make note that it was not at #1 work accordingly the important thing is getting the distributor and rotor back in with the same orientation it came out with.

4) Note the location of the rotor and distributor and mark them so they can be placed in the same orientation when the distributor is reinstalled. Once this is done remove the bolt holding the distributor in place and onto the engine using the 12 mm socket and ratchet. The bolt should be on the right side of distributor.

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Mark the Rotor position on the distributor​

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Mark the distributor location on the mounting bolt​

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Distributor Bolt Removal​

5) Now disconnect the wire connector from the wire harness and remove the distributor by pulling vertically and twisting back and forth until the distributor comes out.

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Distributor Cable Connector​

If you look at the wires going out of this connector and those attached to the coils you should see agreement with the Suzuki wiring diagram.

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Coil Wiring B/W + and Brown -​

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B/W and Brown at Distributor Connector​

6) Block off the distributor whole with the rag or shop towel to keep debris from getting into the engine block while the distributor is removed. Note it is also a good idea to put the 12mm bolt back in the hole so it does not get misplaced.

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7) Once the distributor has been removed you can move indoors amd work on a bench or table as you will not need to be in the engine bay until the work on the distributor internals is complete.

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8 ) Remove the rotor for better access to the components below it. Use the standard screwdriver or needle nose pliers to remove the plastic cover on the internal ignition module. Then use the phillips head screwdriver remove the two screws holding the internal ignition module in place in the distributor.

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9) Use the phillips head screwdriver to take out the screws holding the connectors from the ignition pickup coil to the internal ignition module. Now pull the ignition module andthe wire with the wiring harness connector on it free from the distributor.

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10) Cut off the connector wire from the ignition module leaving about 6 inches of wire pigtailed out from the connector and set it aside. This will be used for power to the GM ignition module and will allow you to utilize the samurai wiring harness too make this a much more plug and play application since brown and black/white wire pairs are already connected into the wiring harness and power in the way we want to use them.

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[K Sparky]

11) Remove the pickup coil connector leads by cutting them off then use wire stripper to take about a half inch of the isolation rubber off of each so that they can be soldered to wires that will allow the sensor to be connected to the GM ignition module externally in the engine bay later. Then heat shrink the connections between the individual wire splices and finally over the pair of wire splices to protect them from damage inside the distributor cap. (Note I used an old computer power cable for this and it turns out that they almost all use a white and green pair of wires which if soldered white to white and red to green give us the benefit of wire color matching module labeling latter)

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12) Now zip tie or wire tie the cable you added to the pickup coil through the mounting holes of the original ignition module so that it will not move or hit the rotor during engine operation and get damaged.

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*** Note it may be possible to swap out the Suzuki igniter pickup coil within 1980s Toyota pickup coil from a Truck, Camry, or other Japanese vehicle with a magneticallytriggered ignition system and distributor. They all have a similar hall effects type sensor and appeared to have the same size and mounting bracket dimensions. I have not tried this yet but it is likely the same manufacturer made pickup coils for most of the Japanese auto makers in the late 1970s to late 1980s timeframe. If this is the case itmay save time and ensure a better connection to get one of these pickup coils and swap it in to. ***

13) Now strip the wires from the other end of the cable that you spliced into the pickup coil wires. These ends will be attached to the GM ignition module. Now either solder them to an ignition module connector and heat shrink them or crimp on spade connectors too each wire and heat shrink them so that you will have secure connectors to attach to the module. Make sure the white wire coming out of the pickup coil attaches to the W terminal on the GM ignition module and the red wire coming out of the pickup coil is attached to the G terminal on the GM ignition module. Again, I used a discarded computer power cord to make my jumper wire between the ignition module in the pickup coil so the white and green wire pair simplified the connection with the white wire connected to the white wire from the pickup coil and the green wire connected to the red wire of the pickup coil thus the wires at ignition control module now matched the terminal lettering white on Wand green on G.

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***I also added a small amount of RTV to the wire where it came at a distributor to filling in the gap where the rubber boot on the previous exit wire used to be. This was to both secure it better and to seal the distributor well. This is probably overkill but it will secure the wire and hopefully keep moisture out of the distributor.

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14) If you look carefully at the small Suzuki ignition module you will see that it has a terminal labeled B and a terminal labeled C just like the GM ignition module does. The blackwire with a white stripe goes to the B terminal and the brown wire goes to the C terminal.

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It is interesting that the GM ignition module has the same labeling and that B and C terminals require the same connections in either module.

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When you look at the Suzuki wiring diagram will notice that the black/white wire goes to the keyed power and to the positive terminal at ignition coil and that the brown wire connects to the negative terminal of the ignition coil. Then if you look at the GM HEI for pin module (GM ignition module) wiring diagram you will see the same that the Cterminal connects to the negative terminal of the coil and the B terminal connects to the positive terminal of the coil and keyed positive power. So, if we wire the system up as follows, we can use the connector that you cut off and set aside earlier and it will match the Suzuki wiring harness and connect the correct terminals of the ignition module to the correct terminals of the coil and keyed power input.

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Take the connector with the pigtails that you cut off the ignition control module earlier and strip the wire back so that they can be either soldered or crimped into spadeconnectors or an ignition module connector and then heat shrunk to protect them and ensure better longevity. Take special care to ensure that the black/white wire goes to the B terminal and the brown wire goes to the C terminal.

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Wire Harness Connector and Ignition Module​

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Wires Stripped​

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Wires connected with heat shrink in place​

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Soldering Iron to ensure better connector conductivity​

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Heat Srinking Harness to B C terminal cable​

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Completed Harness Connection Cable​

If this is cable is made correctly then the wire will just hook back into the original harness through the connector and the GM module and will work just like the Suzuki module did. This should wrap up the modifications that are required before you reinstall the distributor and ignition module in the vehicle.

15) Next with the modifications to the distributor complete and the wiring that will connect the pickup coil to the ignition module finished it is time to go back out and do some work in the engine bay. You will need to find a suitable heatsink to mount the GM control module on to avoid overheating and failure. It is best if it is mounted in a convenient location for hooking up the distributor and harness wiring some place on the firewall the samurai. They sell a heatsink for this exact application on Amazon for 15 dollars but people often use a block of aluminum or computer hard drive heatsink with great success as well. I had hoped the Genuine GM HEI Heat Sink would fit the Ignition Control Module without requiring any modification but that did not turn out to be the case. Not sure why but the hole holes did not line up because of interference at the top and the alignment pegs on the bottom did not match anything.

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GM Heat Sink​

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Check fit to GM HEI Ignition Module​

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Unmodified Heat Sink​

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Hole Misalignment​

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Interference When Inverted​

To get the heat sink to fit center the module in the heat sink as shown and drill two 11/64? holes were the alignment pins stick out the bottom of the module. Before you drill these holes make sure that the through hole do not partially cross the existing holes or you will have trouble drilling the mounting through holes on the next step.

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Module Flush Mounted with Alignment Pins in New Holes​

Next use the module mount holes as a template to start the two 11/64? holes then remove the module and dill the holes all the way through.

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Finally counter sink all the new holes slightly using a step drill of debur tool. This will allow everything to set flush and help heat transfer which is the whole point.

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Make sure the holes line up well between the sink and the module before putting any holes in the firewall mounting.

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Now go position the heat sink on the flat centered on the firewall above and to the left of the distributor and mark the mounting hole locations. Once this is done drill two 5/64? holes for the mounting screws. This location has plenty of flat area for the heatsink to rest flush and is close enough to the distributor and wiring harness connector to work well.

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Apply thermal grease to the back side of the ignition module place it on top of heatsink and attach it to the firewall with two 1 ?? long #8 self-tapping screw. Be sure to put a grounding wire under the screw closest to the B and C terminals securing the screws. If not already grounded secure the other end of the grounding wire that you attached to the module to a good body ground.

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Heat Sink Waiting for Module​

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Thermal Grease Applied ​

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GM HEI Ignition Module and Heat Sink Installed​

16) Reinstall the distributor making sure that all your marks match from when you removed. Pay attention as the helical gears on the bottom of the shaft may require a few installs with slight positioned tweaks to get the rotor pointing to the right position. There are 13 teeth on the gear so being off by one tooth was shift the rotor by about 27 degrees which will not be good for timing the engine. Once the rotor and distributor base are back in the correct location and orientation lock down the 12 mm bolt that holds the distributor down keeps it from rotating.

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Distributor Reinstalled​

Note at TDC on #1 the rotor should be pointing just before the bolt hole and the distributor rotated so that the hole is about centered in the adjustment slot.

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[K Sparky]

17) Attach the GM ignition module connectors or spadeconnectors to the GM ignition module white to the W and red (green if you wired it up like I did) to the G. Reconnect the black/white and brown wire connector back to the wiring harness and attach the ignition module connector so that the black/white wire goes to the B terminal and thebrown wire to the C terminal. Make sure all your connections are to the right locations as shown in the combined system wiring diagram.

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G and W Connections​

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B and C Connections​

18) Replace the stock Suzuki ignition coil with the GM ignition coil. This will allow a better match between the electrical output of the ignition module and the coil will let us avoid having to add a balance resistor to make it operate correctly. This coil upgrade should also provide a hotter spark to the plugs. Once mechanically attached reconnect the wiring terminals ensuring that the brown wire goes to the negative terminal of the coil and the black/white wire goes to the positive terminal of the coil and that the center terminal is connected to the central pole of the distributor. Check the connections for any buildup or corrosion and clean them up accordingly before tightening down terminal nuts at this time.

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No External Resistor Required​

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Old Coil​

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New vs Old​

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New vs Old​

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New Coil Installed​

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Full System Install​

19) Reattach vacuum advance line to disturber and the positive battery terminal.

20) Start the engine and adjust the timing as needed.

21) ENJOY THE RIDE!!!

 

[txgocart]

Great write up. Thanks for the effort to keep the little beasts going.

Ray

 

[K Sparky]

Great write up. Thanks for the effort to keep the little beasts going.

Ray you got any input on things I should make clearer on this? I plan to go back through my part 1, part 2, and part 3 on this and get the pictures imported and change the font size. Still learning the forum stuff.

Kody

 

[beekiller]

I'll help ya clean up the syntax tonight. Where did you upload the pix?

 

[K Sparky]

I'll help ya clean up the syntax tonight. Where did you upload the pix?

At this point I have not uploaded them I just copy pasted from a text document that had the pictures in it. Where should I upload them?

 

[beekiller]

At this point I have not uploaded them I just copy pasted from a text document that had the pictures in it. Where should I upload them?

Ideally just attach them to the post itself. Then you can insert them into the post at the desired location.

 

[Aids10]

I'll help ya clean up the syntax tonight.

SynTax; that's what you give a prostitute afterwards?

 

[K Sparky]

Thanks for all the help ??!!!

 

[beekiller]

Thanks for all the help ??!!!

You're welcome! Thanks for a well done writeup! It will surely help someone.

 

[K Sparky]

Is there an easy way to reduce the font size? I know it is probably just my own preference and the fact that I pasted in larger then normal forum text but it seems a bit excessive in text size now. I saw I could modify it line by line in quick editing but that seems like a lot of work if there is an easy way to do it.

 

[txgocart]

I have no additional input that I can think of.

Ray


Edit Afterthought hopefully people understand that there is a big difference in thermal grease (heat sink compound) and RTV and if you plan ahead then now would be a great time to replace distributor shaft o ring

 

[supazuk]

awesome write up I plan to use this on my 87

 

[K Sparky]

awesome write up I plan to use this on my 87

Please let me know if I need to clarify anything.

 

[TD57]

Great write up & "How To"  
I'm also going with this (parts ordered) - adding this to the many upgrades I have parts for but haven't gotten to  
[member=25021]K Sparky[/member], your walk through is very well explained! Thanks for the upgrade info   [red_s]     [black_s]

 

[K Sparky]

If the ignition module goes out on our 86 I may try swapping in a ?Toyota? ignition pickup coil as shown bellow also just to simplify the spicing and move it out from under the cap. I know the pickup coil shown bellow fires the GM module. It also sure looks like it will just fit right in at the same location but I don?t know for sure. The one shown below is for a 4 runner and is sold in Amazon for 19 bucks. If it fits it could be an easier install but I don?t know for sure if it would work. I will let everyone know when I do!

 

[K Sparky]

I ran the engine with the conversion for over 45 minutes straight this evening while I worked on the basket case stock carburetor and was very pleased with the results. As I cleaned the carburetor and blocked off or reattached open vacuum lines it ran better and better and the throttle response and return to idle got smoother as well. I know the carburetor needs a lot of attention but the ignition system worked fantastically!

 

[Zuki4x4]

Convert into an article!

 

[K Sparky]

Convert into an article!

Is that another forum function? If so how do I do that here?