Toyota 20R - GM HEI Ignition Conversion - With a Ballast Resistor? Yep, Sometimes...

[@dawneandjohn]

As a suggestion, could you do a shorter, updated video that thoroughly shows all the wiring connections with the updated parts you used? Found myself having to refer to your earlier video (8 years ago) for the initial explanation of the wiring and then referring to this video for the ballast resistor wiring. A new hand drawing of the Toyota connections would be amazing too 😀.. for anyone else attempting this repair. Thanks again for all your efforts. ❤

[@The13thSword]

I have considered it but life seems to get in the way, as usual. It's on my agenda but I have no completion date yet.

[@tempura7690]

your research is appreciated!

[@The13thSword]

Thank you. Just putting it out there for the people.

[@Matt-rl5mx]

It's Matt again, I had another question about the "R" on the starter. Did you clip that connector off and run an extension wire to the coil like you mentioned in the video at 19:37. Or how did you connect that wire from the starter? I haven't even looked at my starter yet but just wanted to know what to look for when I get those parts from Rock Auto and start installing everything. Thanks!

[@The13thSword]

My starter looks like this one: www.rockauto.com/en/moreinfo.php?pk=1000818&cc=1277108&pt=4152&jsn=901 The installed wire with connector is the "R" terminal on the starter. The connector should already have a 1/4" male spade terminal in it & I did not clip it off. What I did was to use 14 gauge stranded wire, strip the insulation off the end & install a crimp-on 1/4" female spade connector, to connect with the male spade connector on the starter "R" terminal wire. I then ran the wire as shown in the video, mostly following the power brake booster vacuum hose, around to the coil. I then cut the wire at that point & installed a crimp-on 16-14 AWG #10 ring terminal. The ring terminal goes on the + post of the coil. I also always protect all my connector to wire joints with heat shrink tubing. This prevents corrosion & gives the "joint" a little more mechanical support. Just to be clear, what this "R" terminal wire does is provide the coil with full battery power when cranking for quicker starts. Once the engine starts & the key is released & goes back to the "Run" position, that wire no longer carries voltage from the starter to the coil; it's only active when cranking. The starter solenoid & it's internal contacts acts as a relay, and will only provide voltage to that wire while cranking. Other than that I added some 1/4" wire protective loom around that wire & zip-tied it in several places to the brake booster vacuum hose. Materials list, all Harbor Freight items: 150 pc Terminal & Connector Assortment, Item #67683 - $5.99 Heat-Shrink Tubing Assortment with Case, 127 Piece, Item #67424 - $4.79 1/4" X 14 foot Protective Wire Wrap, Item #66985 - $3.29 8 Inch Black Cable (Zip) Ties, 100 Pack - $1.99 And from Lowes.... Southwire 20-ft 14-AWG Stranded Red Gpt Primary Wire, Item #313147 - $6.63. I have personally spec'ed all these materials and they will handle typical underhood temps. The wire is spec'ed at 15 amps max; the most the coil should draw on cranking is 4-5 amps, so there is a 3x safety margin.

[@Matt-rl5mx]

@@The13thSword thanks again for all of this information! I guess what I need to do first and foremost is check to see if my starter has the "R" connection terminal. Just for example though, if my starter does NOT have that terminal. Would you suggest me replacing it with a new starter with that option? When watching your video, you pointed out that you can get it with or without that "R" connector wire.

[@Matt-rl5mx]

@The13thSword just checked my starter. I have a black with white stripe wire that is connected to my starter. It is routed through the factory wiring harness. Do I disconnect that wire and than run my own wire to the positive terminal on the coil like we've been talking about?

[@The13thSword]

@@Matt-rl5mx There are some differences in how the "Start" & "Run" circuits will work, and how you may or may not have a ballast resistor in circuit. I will explain. With a fully charged battery (typically 12.7 volts), voltage drop when cranking (12.7 volts minus what the starter is using while cranking) is usually about 9.7 volts. The "Run" side of the ignition circuit is powered during cranking, but if you have a ballast resistor installed between that source & the coil, that 9.7 volts will get dropped by the resistor down to about 5.5 volts. This results in weaker spark & may result in it taking more time to actually get the engine started. The "direct" wire from the starter "R" terminal avoids that problem, as it bypasses the resistor & feeds that 9.7 volts directly to the coil's "+" terminal when cranking. The later version of that starter without the "R" terminal was a response to the ballast resistor being eliminated in later models. As I pointed out before, this was due to the "newer" style coils that were designed to actually take full running voltage, like the UC15 coil. The earlier UC12/UF2 type coils were not designed to do that; that's why the ballast resistor was there, to keep those coils running cooler & to make them live longer. With that said, my original starter also did not have the "R" terminal, so my truck was starting on that 5.5 volts fairly reliably, but it would takes several seconds (+/- 3) to start. Now that I have a starter with the "R" terminal, and have it wired as I described, startups are now less than one second of cranking, on a regular basis. Some days it seems nearly instant to me. So in short, it will work either way, with the main difference being in startup crank time, & possibly saving some long-term wear & tear on your starter. It's your choice.

[@The13thSword]

@@Matt-rl5mx The Black with White stripe wire is the "Start" trigger wire from your ignition switch. It provides power to the starter solenoid when cranking (key held in "START" position). Do *not* disconnect that wire or you will not be able to activate the starter at all. Also, you *CANNOT* "tap off" of that single trigger terminal for an "R" coil wire. Because that wire would go directly to your coil + terminal, which would also have the "Run" wire from the ballast resistor connected to it. When the engine starts the Run side would continue to power the starter solenoid & that would be a disaster. Your starter & flywheel would suffer large amount of damage, at a minimum.

[@dawneandjohn]

Does the Ballast Resistor need to be grounded by the mounting screw in it? Hoping to attach it with zip ties and avoid another hole in the truck. 🤞 In another reply you sent me, you mentioned a Standard UC15 coil that has the resistor built in. Unfortunately, O'Reilly Auto Parts doesn't have it in stock so can't get it in the time frame we need to get back on the road. We did, however, order the Standard UC12X coil which is their Blue Streak version. According to O'Reilly, it's a higher quality than the Standard UC12. The Blue Streak line is their top end line.

[@The13thSword]

The ballast resistor used with the UC12 coil does not need to be electrically grounded. It is a "pass through" device, meaning electrical power goes "in" through one terminal and goes "out" through the other terminal. I have mine mounted with a screw just to keep it securely in place. You can certainly secure the resistor with zip ties if it's convenient for you to do so. Just make sure that the terminals & connectors on them don't touch any metal objects or body panels underhood. Going with the UC12 or UC12X Blue Streak is fine as long as you have that ballast resistor in series with the power feed to the coil positive (+). Power passes thru the resistor, lowering the voltage to about 9.5-10 volts, then the power goes to the coil. Either the UC12 or UC12X is designed to run on that voltage and stay reasonably cooler so it doesn't get "cooked" like it would on full battery voltage (13.8 volts average.) Spark power at the spark plugs should be more than ample.

[@dawneandjohn]

​@@The13thSword Thx for the advice. The mechanic here has very limited time to work on the camper, so in the interest of time, we're going to use the can coil for now and most likely upgrade it to the brick style later after we get back home. I watched your video that explains the can vs the brick and I like the idea that a brick runs cooler. I should be able to do the modification when we get back home.... Hence the need to zip tie the resistor for now and not make any extra holes to attract rust. I'll be sure to secure it so the terminals don't touch metal.. as you suggested.

[@Ed-hb5rt]

Thanks for the awesome information! Do you think the steering coupler will work with the celicas as well?

[@The13thSword]

It might but I can't find any specific info to be 100% sure of a direct & correct fit. I would personally assume that it might, as I have learned over the years that Toyota often used the same parts between different models of vehicles. I do see that the same coupler is specified for Land Cruisers as well as for the Pickup, but that's the only cross-reference I can find that's 100%. You'd have to visually check yours out & compare. It's also possible to rebuild your coupler with a new disk & parts. Dorman has several kits for this. www.dormanproducts.com/ Just search the site for "Steering Shaft Coupler" & you'll see all the options available. Several of these kits come with new hardware but you will have to reuse the splined original parts from the old coupler. There are several videos about this on KZbin. The kits are usually available on Ebay & Amazon, as well as at some local parts stores.

[@Ed-hb5rt]

@@The13thSword thanks for your response! Great work!

[@andrewmacbeth8278]

Thanks for putting these videos together! I just got myself a 86 4runner that has immediately stopped running reliably the day after I got it home! Mostly very hard to start and stay running. Swapped out most of the ignition parts now and only left with the igniter or the ecu being my issue haha! I see from your resistance charts that the 22re has very low primarily and high secondary. The accel one I got (only one available at my local flaps) is 1.4ohms primary and 9.2K secondary. So it’s out of spec (although they recommended it fit my truck). So if I do this conversion ai should look for a lower primary resistance coil, and I’m in the clear for adding a resistor inline since I have the newer style from what I understand. As for hooking it up, I’m pretty confused since I have 7 wires going into my oem igniter and only need 4 for the hei ignitor?

[@The13thSword]

I'm glad that the videos have been of some help to you. I would not recommend that you do the GM HEI module conversion on a 22RE. The 22RE (the "E" standing for Electronic Fuel Injection) is an entirely different system compared to the 22R version, which has a carburetor instead of fuel injectors. The ECU for a 22RE is totally different than for the 22R version, and it is designed to work in a different way. The Igniter & ECU are interdependent, meaning that the ECU to some degree also controls the Igniter. On a 22R with carb, the ECU mostly controls the emissions system & has little to nothing to do with the Igniter. That said I'll take the rest of your comments in order. Definitely get your Ignitor & ECU tested at a parts store BEFORE you go buying new ones. Both items new can be expensive, & there is no sense replacing a working unit. Get them tested to be sure they are or are not an issue first. About Ignitors, Ignition Modules & Ignition coils - The design of the coil must be matched to the design of the Ignitor/Module, or you're going to have further ignition issues later on. I don't know what Accel coil you have there (assuming you might have an Accel #8140?) but for the stock Ignitor to work, that 1.4 Ohm Primary resistance is too high for it to work properly, and could possibly burn out a stock Ignitor. The specs I posted for an '86 are correct for either the 22R or 22RE; 0.5 to 0.7 Ohms Primary, 11,400 to 15,600 Ohms Secondary. The Ohm rating of the coil is design matched to the Ignitor for maximum efficiency & performance. Your Accel coil (regardless of who recommended it as appropriate to your application) has twice the Primary resistance. That literally means you are only getting about half the spark power that the engine was designed to run on. Not good & that could easily cause the running problems you are having. I would suggest (ideally, for good performance & parts longevity) that you go with a stock setup like the engine originally came with, i.e. the correct stock Ignitor & coil. The correct Toyota coil is this one: www.toyotapartsdeal.com/oem/toyota~coil~assy~ignition~90919-02113.html I said all of the above because Toyota engineered these systems to work well & long, & I don't think any modified system used to replace it would be as good or any better than the stock system. I only did my modification because new OEM-style parts are no longer available for my truck. You can get a good quality aftermarket coil with the correct spec for maybe less money, brands like NGK, Standard (SMP) or even NAPA Echlin. Just don't cheap out on the coil because cheaper lower quality coils just don't last or perform well. I learned this the hard way from personal experience. Other notes, RE: hard to start won't stay running. I have heard that on 22RE's a lot of the time this is fuel related, not ignition related. Some items that seem to pop up most often are the Fuel Pressure Regulator, the Cold Start Valve & the Cold Start Valve Timer. You could also have one or more vacuum hose leaks. I strongly suggest that you get (if you haven't already) a shop manual for the truck, like the Haynes 92075 manual. Just google that & you'll see them. I hope all of this is helpful. If I can help with any other info just ask.

[@dawneandjohn]

The original OEM Ignition module came with 3 green harness plugs. 1st green plug connects to your 2 red power wires that you ran to the resistor and B terminal 2nd green plug connects to the 2 wires to the distributor And what is the purpose of the third green plug that was left unconnected in your truck? Is it a another power wire, negative wire, or something else? Do you know what device it was running in your truck? Emissions maybe? In your video, it's under the voltage regulator box. It looks like a dangling green plug (with nothing connected to it) with a single yellow (?) wire that runs into a bundle of wires on the side wall. If I knew what the extra plug/wire was for, it would help determine the function of that mystery ECS box we've got in our camper. It's quite possible it's an emissions module (?) instead of a cruise control module. Why was it left unconnected in your ICM upgrade? I looked on ebay to see if they made different OEM ICM's for the 1978/1979 20R pickups, but they all look like they originally came with 3 green plugs. Your timely help is greatly appreciated. I got the parts today. I plan on doing the heat sink mod and prepping some of the wires today to help save time for the busy mechanic. Our neighbor here is going to deliver them to the mechanic tmrw on his way to work so I need to get everything done today.

[@The13thSword]

See previous response about the 3rd green plug. And yes you are correct, on my '78, that one runs to the old emissions control "computer" box mounted to the driver's side kickpanel in the cab. I have also unplugged the "computer" connecter from the box, as it's no longer needed once the vehicle has been "desmogged".

[@dawneandjohn]

@@The13thSword Thx. I'll have to take another look at the kickpanel area next time we're at the camper. I remember seeing 2 black boxes mounted there... both with wiring harnesses. Now that you say that yours was an emission box, I'll see if I can trace the wires for each of the boxes. It's quite possible the camper has an emissions box AND a cruise control box mounted on the kickpanel. I'll let you know what I find out. We should be seeing the camper again within the next few days.

[@pablocuate]

@The13thSword I have a 12v run circuit wire that was connected to my coil +. Can I use that 12v run circuit wire in a Y connection to connect the resistor to the coil + and branch off the other wire to connect to the B terminal of the module?

[@The13thSword]

What you're asking isn't exactly clear to me but I'll give this a good try at an answer. It all depends on what coil you are using. The "original style" coil (similar to a Standard UC12 coil) is designed to "run" on less than full battery voltage, so the resistor would be required. On the other hand, if you use a coil that is internally resisted (like the Standard UC15), you don't need the external resistor, and that coil can be directly wired into the "run" circuit, And by "run circuit" I mean power coming from the ignition switch "run" side, not the "start" side. What I think you're asking here is whether or not the module "B" terminal should get resisted voltage or full battery voltage. The answer is the latter: the module "B" terminal should get full battery voltage, as that's what it was designed to work on. So, if you are taking full battery voltage off that "Y" connection BEFORE the resistor, you should be good. If that "Y" connector is AFTER the resistor, not so good. I hope this helps, If you need any other info just ask.

[@pablocuate]

@@The13thSword Thanks for your reply. I will be using the following: GM 4 prong hei module GM heat sink for module Arctic mx-6 thermal paste Standard Ignition Coil - UC12 Duralast Ballast Resistor CR107 The car I am working on is a 1975 Toyota Corolla with a 3tc engine. It has a starter solenoid (same style as Duralast Relay F496) wired in already. The i post of the starter solenoid is what will provide full 12v power to the positive of the Standard UC12 Coil only when switching the key to start. I gather this is the equivalent of the R terminal on your starter. Standard UC12 Coil negative will connect to C prong on GM Module My distributor has an electronic ignition conversion (hot-spark electronic conversion kit). The white wire from the distributor will go to the W prong on GM Module. The red wire from distributor will go to G prong on GM Module. My confusion is on whether I can use a butt connector on my single 12v run wire which on the other end of the butt connector would be two wires, now giving me two 12v run wires to use. One of those wires will lead to the ballast resistor that will connect to the Standard UC12 coil positive. The other 12v run wire will connect to the B prong on GM Module. I ask this because I’m not sure if some sort of circuit needs to be completed or if the 12v run wires only provide power to their respective connections and that’s it. You have two 12v run wires located in that plug. I have one 12v run wire which I want to turn into two. I’m not much of an electrician so I am grateful for your guidance. You’ve simplified everything so well, i just ran into this hiccup.

[@The13thSword]

@@pablocuate First, thank you for the very detailed response, it makes my end of it easier to understand what you exactly have going on there. Your parts selection is excellent and appropriate. Your thought on the "I" post on the starter solenoid being the same as the stock Toyota "R" terminal is correct. The rest of your wiring description is 100% correct. Your idea on using a butt connector to turn the single 12v run feed into 2 (two) 12v run feeds is simple & direct. Again, good thinking. You are in essence creating a "splitter". The splitter creates two independent feeds and as long as each feed to a device has it's own ground completion point, you're good to go. The ground side of a circuit completes the circuit. The ground for the coil feed is through the coil via it's negative (-) post, back through the module via the "C" terminal & then on through the module to the module's ground. This is the module's mounting hole/tab on the "B/C" end of the module. A very substantial & solid ground here is crucial. Both devices (coil & module) can share a common ground like this with no problems. Just make sure you have a good, clean ground connection to whatever ground point on the vehicle you will be using. I.E. a body ground needs to have good contact points all the way back to battery negative. You can verify a good ground point with an Ohm meter. Meter positive lead to battery positive OR your proposed 12 volt feed when "hot" (energized), negative lead to proposed grounding point. A good ground point should read 0.1 Ohm or less. You can also run a ground wire direct to the car's frame, engine block, cylinder head, etc. I recommend no smaller than 16 gauge stranded wire for this, but I personally prefer 14 gauge. The only other thing I wanted to mention was the air gap setting on the distributor pickup coil, as I have found that getting this correct is crucial to the module getting the correct signal level to switch on & off as designed. Too large of an air gap at the pickup coil can result in signal strength being too low to trigger the module. On your Hot Spark conversion, they specify that the air gap: "Should be somewhere around 1 mm (.040 inches), but the exact gap is not critical, it can be more or less, as long as the magnet sleeve doesn't rub against the ignition sensor and you can see daylight between all spots on the magnet sleeve and ignition module." Source: www.hot-spark.com/Troubleshooting.pdf You should verify that the air gap is within spec with the correct thickness of feeler gauge, and make sure that when you have the correct gap, any adjustment/lock-down hardware is well secured so the gap doesn't change on you. That's all I can think of for explanation. Everything sounds like you're on the right track. Let me know if anything else comes up and/or how it turns out.

[@dawneandjohn]

Can the Standard "brick" UF12 be used with the Standard LX301 module (instead of the UC12 "can" version)? (Then the resistor could be eliminated) I realize the original coil bracket may need some modification if using the UF12. Also, would the extra finned heat sink (ACDelco 104746610) be necessary if using the Standard UF12 coil with the Standard LX301 module? We've got a 1979 Toyota Pickup 20r with a camper body attached to it (it's actually a Toyota Pony Camper... the camper body is built onto the truck). (It's considered a 1st Generation since it was built in 1978, but released as a 1979) In our case, I think we'd like to have the extra performance since the engine really struggles uphills. We'd like to get as much "oomph" as possible. We recently had the engine rebuilt, and did the Weber aftermarket carburetor too. Also got a rebuilt distributor too (to match the original OEM style). Thx. Dawne

[@The13thSword]

From my research and as near as I can tell, yes you could use the Standard UF12 coil or similar other brand, as long as it's a quality coil. Avoid any of the "cheapies" out there, they will only give you headaches & possibly strand you on the road. Alternate brands/part numbers: NGK - 48784, WVE/Wells - 5C1291. Also, any quality ignition coil of the later "brick style" intended for the 22R carbureted version of the engine (NOT EFI), up to model year 1990, will work with the HEI module. You are correct, the later "brick style" coils do not require an external resistor. I highly recommend using the heat sink for the HEI module regardless of the coil used. The module has several power transistors in it that generate heat that need to be "channeled away" by a heat sink, so that the module doesn't get "cooked'. As far as the engine struggling uphill, what kind of transmission do you have in that camper? Auto? 4 Speed? I know a lot of the "dually" Toyota campers ('75 & up) came with either of those 2 transmissions and while they are OK for general traveling, they aren't too stellar of climbing hills or highway driving especially. The "standard" solution to this was replacing the Auto or 4 speed manual with the 5 speed manual, usually the W50 or W56 trans. While this won't help much with hill climbing, as they have the same 1st thru 4th gear ratios as the 4 speed manual trans, they do have an overdrive 5th gear that make highway driving better.

[@dawneandjohn]

Thanks for the info. 😊 It's my mom's camper. She says it's got 3-speeds with overdrive... so is that considered 4 speed? She had the trans rebuilt about 2017. As far as we know, it's the original. Regarding the ignition coil/module: I spent most of yesterday watching your VERY HELPFUL videos (and some others on KZbin too) to learn about the ignition module upgrade. Sooo thankful you took the time to post these videos!! ❤ We're currently temporarily stranded in Kentucky and our camper is having backfiring/stalling/chugging issues. The local mechanic replaced the coil with the Standard Igntion UC12 coil (with no resistor) and we got an original used module from eBay (which we believe to be defective... plus it's over 45years old) so we're looking into doing the upgrade to the LX301. (We didn't know of the module upgrade until after buying the old module. 🥴 Luckily we can still return it) The engine was just rebuilt 1500 miles ago, got new Weber carb, eliminated the emissions/smog stuff, new remanuf distributor (original design), and new plugs/wires. We drove about 1200 miles and camper started intermittently chugging. Then it got progressively worse. Then it started backfiring upon deceleration. So much so, the muffler blew open and eventually ignited the plastic sewer tank while on the highway. Luckily, a trucker saw the flames and brought us a fire extinguisher and water to get most of the fire put out before the fire dept arrived. Luckily, the camper sustained minimal damage and was towed to the local mechanic. Mechanic noticed the module and coil getting SUPER hot so he replaced the coil and we got the used ebay module. Still has same backfiring and stalling issues after driving 2-3 miles when the engine heats up. Mechanic also found a faulty ignition switch too. We're hopeful that with a new switch, and the module/coil upgrade (explained in your videos) will help get the problem fixed so we can get back on the road and back home to New Hampshire. 🤞

[@dawneandjohn]

​@@The13thSword...and yes, we plan on using the quality parts from Standard that you recommended in the videos. There's an O'Reilly in town that has the Standard LX301 module, Standard RU-4 ballast resistor, ACDelco 10474610 heat sink, and Standard UC12 coil. At O'Reilly, all parts mentioned (except the heat sink), have a lifetime warranty. The local Walmart has (in stock) the "Corsair TM30 Performance PC Thermal Heat Paste" so we'll use that instead of the silicone paste that comes with the heat sink. Yes, Rockauto has better pricing, but we're trying to get back on the road asap so time is of the essence. 😊

[@The13thSword]

@@dawneandjohn I would consider that to be the standard stock 4 speed manual that came with a lot of the campers. It should be either the Toyota W40 or W42, specs here: en.wikipedia.org/wiki/Toyota_W_transmission#W40 The 4th gear isn't overdrive, it's a straight 1 to 1 ratio. The W50 & W56 5 speed manual trans have the same gear ratios as the W40/W42, 1st thru 4th gear, but 5th gear is an actual overdrive gear at 0.853 to 1. Sorry to hear about the stranding. The UC12 coil will work for a while without the resistor, but not for too long. It's not designed to take full running battery voltage (13.8 volt average from alternator) without the resistor in place. If you still want to skip the resistor go with a UC15 coil. It's internally resisted so you wouldn't need an external resistor & you can power it direct from running battery voltage. It sounds to me that the UC12 is already starting to have problems from running on that full voltage without the resistor to protect it. I'm 80%+ sure that if you install a UC15 most or all of those symptoms will go away. If a new UC15 still gives the same issues, then it's the original used module. Thanks for the very extensive & complete info you provided. Well done. The near fresh rebuild on the engine; running fine when you left home, drove 1200 miles then problems arose, then got worse, super hot coil & module etc. All of this sounds like a failing ignition coil, and are (mostly) the exact symptoms I've dealt with in the past with this. When the coil starts overheating it develops higher internal resistance, either on Primary or Secondary, or both. This condition can fairly easily cause damage to the module. Most GM guys will tell you that when an ignition coil starts to go bad like this, it more often than not also takes out the HEI module, so they both have to be replaced, usually. The faulty ignition switch is just another added source of excess resistance. The ignition system isn't on a relay, so there is full battery voltage (12 volts+) going thru the ignition switch. Over time & use, the contacts inside can get worn, dirty, corroded, pitted, etc. & cause excess resistance. I was a good move to get that replaced. I see several other messages from you, which I will answer in turn.

[@The13thSword]

@@dawneandjohn Completely understandable. IMO the CPU paste does a better job than the plain silicone paste. I only recommended Rock Auto because I assumed you to be working on the truck at home.

[@dawneandjohn]

1) What is the black box that you attached the ground wire to? 2) Do you know what an ECS P/N 4714A module is? In our camper, the ECS is mounted on the side wall directly to the left of the black box in question #1. It's slightly smaller in size. In trying to understand the wiring for the new LX301 module, our 1979 Toyota Pickup (Pony Camper) has this mystery ECS black box/module that's not part of the wiring that you have in your truck. On the left of the ECS box, there's a brown wire that runs thru the firewall and into a harness that's attached to a cruise control module (located in the driver's area, under a fuse box). It also has a small green wire that I believe is a ground. On the right of the ECS is a yellow wire that runs to a green harness connector that comes off the original Ignition Control Module. If you need more pics/info, I could post a video to my KZbin if needed. Just let me know and I'll edit & post something for you.

[@The13thSword]

1. If you mean the black box on the inside fender wall, that should be the voltage regulator. I ran my ground for the ignition module to one of the mounting bolts for it, to use the body ground. The module doesn't have to be specifically grounded to that specific point. It just has to be be grounded to a clean, solid ground point, which can be anywhere on the engine, frame or body. I just grounded it there for convenience & to keep the wiring tidy Word of warning & advice: There is a cable attached from the back of the cylinder head to the firewall, This is the engine-to-body ground cable. Have your mechanic check that cable for any resistance above 0.1 ohm; if above that, replace that ground cable. That cable is what provide a good ground to the body so if you have extra resistance on that cable, the body ground may not be good enough to use to ground the module. Ground cables as they age can develop higher than spec resistance. If it's original, it would be wise to go ahead & replace it with a new cable. How can you tell if it's original? Toyota factory ground cables for 1972 to 1980 are black with a yellow stripe. Otherwise, it just has to be measured end to end with an Ohm Meter to see if it's still in spec or not. Spec should be 0.0 to 0.1 Ohm. Don't forget to check & clean the terminals & clean any metal contact areas. 2. Near as I can tell from research, that part number is an ignition module for a 1989 Isuzu Trooper 2. From what I can tell by pictures, it looks just like a 7-pin version of a GM HEI module, which doesn't surprise me a bit. GM & Isuzu has a working partnership in the 80s & 90s & parts sharing was common. And no, I don't recommend using that part on your application. You only need the common 4 pin type. Reading further it sounds like at some time in the past, someone else rigged up a stock ignition module bypass system using the Isuzu module. If true, the wire colors may be of no help, as a lot of people just use whatever wire they have on hand to get things working. Basic wiring for the LX301 Module (standard 4 pin HEI module) - Mounting hole with "tab" on top (nearest side to the "B' & "C" terminals) - Ground wire to body/frame/engine/battery/your choice of location for a good & solid negative ground. "B" terminal - full system/battery voltage (*) "C" terminal - to Ignition Coil negative (-) terminal. "G" terminal - red or pink wire (may present as either color) from distributor pickup coil "W" terminal - White wire from distributor pickup coil. Of course, the ignition coil positive (+) gets connected to a power source from the ignition switch. On my '78 there is a double terminal green connector coming from the harness right on top of the driver's side wheelwell. The two wires from the harness going into the green plug are Red with Black stripe. Both of these terminals are "hot" with the ignition switch in either the "RUN" or "START" position. I tapped off one of these terminals to power the ignition coil, and tapped off the other one to power the ignition module. Further note - use an Ohm meter (or have someone do this) to check the resistance of the distributor pickup coil. Spec should be 130 to 180 ohms. I doubt it's an issue by it never hurts to double check.

[@dawneandjohn]

​​@@The13thSword Thanks for the detailed info. I've been suspecting all along that we might have a grounding issue. I super appreciate the details on how to test it. 🤩 I'll either check it myself (next time we get a ride to the camper) or ask the mechanic if he has time. Re #2... I did some looking online too for that part too and couldn't find anything... at least under Toyota. I just edited and uploaded a video for you here on my personal KZbin channel that shows in more detail about the ECS unit and what it's hooked up to... and some footage of our fire too. The more I look at it, the more I'm convinced the mystery ECS box is part of a cruise control system.... maybe🤔. It doesn't make sense to me that someone would install 2 ignition control modules... but then again there is some weird wiring on the camper that someone else did before my mom bought it in 2017. ...Dawne

[@dawneandjohn]

​@@The13thSword How do I wire in the ECS box to the Standard LX301 ignition control module? I made a video showing the ECS box wiring and uploaded it to my personal channel. I tried enclosing a link to it in a previous comment , but I think it got deleted. 🤔 KZbin apparently restricts video links in comments. 😕 If you click on my galaxy-looking profile picture on this comment, it will bring you to my profile. Just select the Video tab. It's the only video listed there. The ending has some footage of our adventure too.❤ ...Dawne

[@The13thSword]

@@dawneandjohn I had a look at the video, thanks for posting it. I'm just glad that the fire wasn't worse & that no one got hurt. wowsers. Many thoughts here. Explanation on the huge "back-fire" in the muffler. The muffler exploding is extreme but does tell me something. Most vehicle exhaust "back-firing" is usually caused by unburned fuel vapor collecting inside the muffler, which then gets ignited either through a very hot surface (less common), or very hot exhaust gases (product of fuel/air mixture actually being burned). Intermittent spark can easily cause this to happen. So if the ignition coil or module have been "cutting out" here and there, that means unburned fuel/air. Then when it does spark, the super hot actually burned air/fuel acts like a spark plug in the muffler & explodes all that unburned air/fuel. This is basically what happens in your engines' cylinders but in a much more controlled manner. I always suspect higher resistance grounding cables in older vehicles. The copper inside just gets fatigued over time & use. You can check them for yourself if you can get your hands on a volt/ohm meter & I'd be happy to provide instructions on that if needed. Harbor Freight has a usable meter for about $7. Given the wiring layout I see in your vid I agree with you, that other "module" controls the cruise control. Not to get too far off the point but it is literally a switching unit, much like an ignition control module, & it could be used for both, theoretically. Good call on identifying the cruise control diaphragm. .👍 Hmmm. I'm getting a thought here. You seemed to indicate that the cruise control didn't/doesn't work too well. Looking at your vid and tracing the "hot" power side from back to front (opposite of how you traced it in the vid) here's what I see. There are two red wires in the harness that have been tapped into for power, one red, one yellow. The yellow from the cruise control module seems to be the power feed for the ignition coil(?) I'm wondering if that cruise control module might be a problem. If it's acting like am intermittent malfunctioning switch, it might/could affect the power getting to the ignition module, or the ignition coil, or both. If the cruise control doesn't work I'd disconnect it from the circuit entirely & see what happens. That yellow wire going to the cruise control module seems to be terminated with a plug, so it might be easy enough to just unplug it & take it out of the circuit entirely to prevent any possible interference with the ignition circuits' functioning. RE weird wiring. You never can tell what some previous owner, with or without knowledge or skills, did with wiring on a vehicle. And especially with camper models which have a bunch of added on electrical items. Par for the course. Good thing here is that before this ignition problem popped up, everything was working, so hopefully you shouldn't have to many other problems to deal with once you get it running again.

[@The13thSword]

@@dawneandjohn I wouldn't, since that "ECS" box could be suspect. Also, it's not good practice to have more than one powered device in a series circuit. A series circuit has a single power source, but several devices, and the power has to pass thru the 1st device to get to the second device, etc. If a device "upstream" in the circuit malfunctions or fails, it will affect every other device "downstream". Think of the electrical flow as a literal stream of water. If that "ECS" box is the first item in that stream, but is malfunctioning it creates a dam in that electrical "stream". Other device(s) downstream won't get that electrical "water" & won't function properly If the "dam prevent any water from flowing at all, those devices downstream simply won't function at all. This is what I meant in my previous reply about that "ECS" box possibly interfering with the ignition coil or module. For a visual example of a series circuit look here: c03.apogee.net/mvc/home/hes/land/el?utilityname=citizenselectric&spc=foe&id=4707 As you can see, if the first powered light bulb malfunctions, it will affect the bulbs "down the line'. The power has to pass thru the first bulb to reach the next one. If the first bulb is your cruise control module and it's intermittently switching on & off (malfunctioning), then the power going "downstream" to the ignition circuit is intermittently switching on & off. Not good. From what I can see in your vid, the "ECS" box is wired in series for power with the ignition components, with the ignition components being "downstream". I don't know who added the cruise control items but they did it the wrong way. If you want to keep the cruise control items powered but not have any possible interference there is a (correct) way to do it, and that's a branch circuit. You can "branch off" the single power feed from the ignition switch (red wires in harness that those red & yellow wires are spliced into). That way each powered item will have it's own separate power feed, and if any "upstream" device malfunctions or fails, it won't effect the power feed to any other items. I don't mean to get so technical on this stuff, but I do want to explain how all of this works so at least you can have a grasp on how it all works, or doesn't work, as the case may be.

[@dawneandjohn]

Is the Standard RU-4 directional or non-directional? I just got one and there's no instructions in the box. When looking at it with the mounting hole at the top, the left terminal has "1 3" engraved on it. The right terminal is blank. Is the left terminal the "IN" side (with the "1 3" writing)? In the video, I see the IN power wire is on the left terminal. However, in the video you mention that it should say "1 4" on the terminal. Mine says "1 3". I'm just double-checking in case the manufacturer decided to change things since you posted this video. ...Dawne

[@The13thSword]

Thought I previously said something about this, but you're right to double check on it, no problem. The resistor is just a "pass-through" device and has no polarity to it. It doesn't matter which side is used for "in" or "out", it will work the same either way. Direct answer is, it is non-directional. BTW the "1.3" stamp on the terminal means the resistor has a 1.3 Ohms resistance rating, which is correct for the application. Resulting voltage to the ignition coil should be right at 9.5 volts. Perfect.