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Yes, there are a number of videos on this topic including parts#s etc. Any good mechanic should be able to do the conversion easily if you don't want to deal with it. My mechanic actually re used the Toyota module housing, replaced the failing part with the GM part. It looks 100% from the outside but the guts are GM. I think he added an additional heat sink underneath.
Yea the gm coil might be the answer.
theres another thread abt someones engine oil smelling like gas just a few threads down. Lots of info on coil stuff there too. Should be enough for you to test yours
Ignitor/igniter= icm. Silver box with lots of wires
Coil= distributor coil. Black thingy with 2 wires and one wire to distributor.
A lot of ppl including toyota and all the manuals use different names for all these things and it can be confusing. I believe the gm mod is replacing your icm with the gm module and linking it to your yota coil
So i guess i confused you when i said gm coil, sorry abt that. I should have said gm ignitor module.
But still do a resistance test on your coil before buying anything else. New doesnt always mean ir works right
Resistance tested the coil and it's within specs. I'm a little hesitant to go with the GM ignitor. I feel like I'm going to get myself dug into a hole I can't dig out of once I start cutting and splicing wires. What would be another option aside from having to convert to a GM coil? How would you resistance test the igniter?
these are for a 1980 with 20r but maybe it will help.
Google the fsm for your model year. Factory service manual. Free Pdf should be on the net. Hard copies for sale on ebay
The book says spark wires max resistance is 25 kilo ohms. Wires are a regular maintenance item. They may last 10 years, who knows. Cheap ones often dont last long and have high resistqnce to start with so you may get weak spark from that.
id try testing wires cold then run engine up to temp for a while and shut it off and test wires again.
The book says spark wires max resistance is 25 kilo ohms. Wires are a regular maintenance item. They may last 10 years, who knows. Cheap ones often dont last long and have high resistqnce to start with so you may get weak spark from that.
id try testing wires cold then run engine up to temp for a while and shut it off and test wires again.
Sounds good . I'll check that real quick and report back. *salutes*
Good work swampedout. Just want to add a few things that may help out Manuk.
The correct Ignition Coil Resistance specs for the 82 are:
Primary - 0.4 to 0.5 Ohms, Secondary - 8500 to 11,500 Ohms
Coil should be tested cold/ambient temperature. If Primary measurement is even 0.1 Ohm over (0.6) I'd replace the coil. If Secondary measurement is within 10% of the upper end (10.350 or higher) I'd also replace the coil.
I know you said the coil was new, but what brand & part number is it? There are a lot of poor quality cheap coils out there and I have found the hard way that they cause issues and don't last. Never cheap out on an Ignition Coil, always buy quality.
If you have a new coil, I assume you suspected your old coil was going bad? If so, failing ignition coils can damage the circuitry in the Igniter/Ignition Module. The only way to know for sure is to remove it from the truck & have it tested at a parts store like O'reiley's, who usually does this for free.
Besides, the part should still be under warranty. The modules they sell are good quality but they can still be damaged by a bad coil.
You said "I'm wondering if something is heating the ICM up to a temp that's causing it to stop functioning."
Maybe, but there is another component part of this system that can act that way too. That is the Pickup Coil in the Distributor. Just like an Ignition Coil, it too can get shorts in it's wiring, or have higher than normal resistance under heat stress. It can also get out of adjustment if it's hold-down screws get loose.
The Pickup Coil is basically a signal generator that sends a pulsed signal to the Igniter, telling it when to "fire" the Ignition Coil so if it's not working right when heated you may get the symptoms you describe.
You can resistance test this coil with an Ohm meter at it's connector. The spec is 140 to 180 Ohms. Just like the Ignition Coil it should be tested "cold". Any cold reading of 165 Ohms or more it needs to be replaced. Best practice here is to replace the entire distributor because if this part is age wron, then the rest of the distributor might not be in such great shape either.
Good news there is that new distributors for your truck aren't expensive. I recommend one from Cardone if you need one (P/N 84731): https://www.rockauto.com/en/catalog/...stributor,7108
The Pickup Coil also has a spec for the air gap, which is the space between the coils face & a vane on the metal rotor that spins by it (see pics on the Rock Auto listing above). The spec is 0.2 mm to 0.4 mm, or 0.08" to 0.16"
If somehow the hold-down screws got loose & the coil backed away from the rotor, you might have weak or no signal.
Extra Info:
swampedout is right, NGK wires are good quality.
The GM HEI Ignition Module Mod is usually done because of the high cost of "stock style" Toyota Igniters/Ignition Modules. The GM Modules are usually no more than $30 for a good quality one, and will operate just fine with the Toyota Distributor& Ignition Coil.
Also, you don't have to hack up your original wiring to get it done either. I just made some jumper wires with solder-on male spade lugs on one end, that can be pushed into the stock connectors. That preserves the stock wiring setup.
If it turns out you need to replace the distributor, here's a great video on how to do it:
Good work swampedout. Just want to add a few things that may help out Manuk.
The correct Ignition Coil Resistance specs for the 82 are:
Primary - 0.4 to 0.5 Ohms, Secondary - 8500 to 11,500 Ohms
Coil should be tested cold/ambient temperature. If Primary measurement is even 0.1 Ohm over (0.6) I'd replace the coil. If Secondary measurement is within 10% of the upper end (10.350 or higher) I'd also replace the coil.
I know you said the coil was new, but what brand & part number is it? There are a lot of poor quality cheap coils out there and I have found the hard way that they cause issues and don't last. Never cheap out on an Ignition Coil, always buy quality.
If you have a new coil, I assume you suspected your old coil was going bad? If so, failing ignition coils can damage the circuitry in the Igniter/Ignition Module. The only way to know for sure is to remove it from the truck & have it tested at a parts store like O'reiley's, who usually does this for free.
Besides, the part should still be under warranty. The modules they sell are good quality but they can still be damaged by a bad coil.
You said "I'm wondering if something is heating the ICM up to a temp that's causing it to stop functioning."
Maybe, but there is another component part of this system that can act that way too. That is the Pickup Coil in the Distributor. Just like an Ignition Coil, it too can get shorts in it's wiring, or have higher than normal resistance under heat stress. It can also get out of adjustment if it's hold-down screws get loose.
The Pickup Coil is basically a signal generator that sends a pulsed signal to the Igniter, telling it when to "fire" the Ignition Coil so if it's not working right when heated you may get the symptoms you describe.
You can resistance test this coil with an Ohm meter at it's connector. The spec is 140 to 180 Ohms. Just like the Ignition Coil it should be tested "cold". Any cold reading of 165 Ohms or more it needs to be replaced. Best practice here is to replace the entire distributor because if this part is age wron, then the rest of the distributor might not be in such great shape either.
Good news there is that new distributors for your truck aren't expensive. I recommend one from Cardone if you need one (P/N 84731): https://www.rockauto.com/en/catalog/...stributor,7108
The Pickup Coil also has a spec for the air gap, which is the space between the coils face & a vane on the metal rotor that spins by it (see pics on the Rock Auto listing above). The spec is 0.2 mm to 0.4 mm, or 0.08" to 0.16"
If somehow the hold-down screws got loose & the coil backed away from the rotor, you might have weak or no signal.
Extra Info:
swampedout is right, NGK wires are good quality.
The GM HEI Ignition Module Mod is usually done because of the high cost of "stock style" Toyota Igniters/Ignition Modules. The GM Modules are usually no more than $30 for a good quality one, and will operate just fine with the Toyota Distributor& Ignition Coil.
Also, you don't have to hack up your original wiring to get it done either. I just made some jumper wires with solder-on male spade lugs on one end, that can be pushed into the stock connectors. That preserves the stock wiring setup.
If it turns out you need to replace the distributor, here's a great video on how to do it: https://www.youtube.com/watch?v=u6b-vnsk5xA
Hope this helps.
Awesome awesome info! Thank you. I went ahead and tested the resistance in the pickup coil. I'm coming up with about 180.5 ohms. Couple questions...
1. You mentioned the wear and tear on the entire distributor unit if the pickup coil is bad. I might as well go ahead and replace the entire unit, correct? (Fyi, I have 208k miles on the odometer)
2. Will the new unit have all the necessary parts? Ex: pick up coil, vacuum advance, etc. RockAuto has pretty cheap prices. I got quoted at Pep Boys and O'Reilly's near me for just under $200 for a new unit smh.
3. I feel like I'm getting a little bit all over the place so my apologies in advance. The truck also doesn't start when it's completely cold. Same exact symptoms. Cranks, turns over and no spark. IDK if this info helps. Just another symptom Ive been having. I'm hoping it'll make things a little bit more clear. Thanks again
Also, I tested the coil I had replaced recently. I have .7ohms in the primary so seems like it's out of specs. I bought it from O'Reilly's. Brand is import direct. I will attach a pic with the part number.
If the Pickup Coil is reading 180.5 Ohms cold then I would say it is your most likely culprit. These units only generate a voltage of 3-5 volts DC, so any excess resistance in it would drop that down to a point where the signal is too weak to trigger the Igniter/Ignition Module.
You're already up against the high end of the spec and as it get heated from engine heat, the resistance is only going to go up higher, weakening the signal further.
Answers to questions:
1. If it's the original distributor I say sure, go ahead and replace with new. If you don't know if it's original or not, just have a very close inspection of it and make a determination. Most likely it is original at 208K miles. You are likely to have wear to bearing, the shaft, weakened advance weight springs and possiblly even built up debris that can make the advance weights sticky & not move freely like they should. All of these things can affect run quality.
If you have a Volt/Ohm meter you can also test the Pickup Coil for voltage. Just hook the meter up the same way you did for the resistance test but put the meter on the 250 AC Volts Range. Crank the engine over & watch the meter.
The result will NOT be steady voltage as it generates AC (alternation current) voltage, so you will see the meter "pulse" numbers, if you see anything.
Again, it only puts out about 3 to 5 volts so you have to watch the "pulses" on the display carefully. At the least this test will tell you if it's putting out voltage or not.
2. The new distributor will have all the parts that you need pre-installed & calibrated, except for (usually*) the Rotor & Cap & Spark Plug Wires; you will usually* have to provide those.
*The pic on Rock Auto shows a Cap in place, so those parts may actually come with the brand new unit. I always assume I have to provide the extra parts I listed as I usually buy rebuilt units.
As a matter of routine, I check the Air Gap Spec I mentioned before installing, just to be sure it wasn't set on a Monday, if you know what I mean.
When it comes to older vehicles like ours, I've found that most part stores don't carry stock of parts, or even if they do or have to "special order" it, the prices are fairly high. Rock Auto doesn't have that problem, as they tap over 2 dozen different warehouses & suppliers to fill orders. Plus their operating overhead costs are much lower; e-commerce vs retail store, so they can offer much lower pricing. No I do not work for Rock Auto and I am not sponsored by them. :^) Please also note that the price you see does not include shipping charges, but even with those added in, the price is almost always lower than getting it from a parts store.
Last thing about that distributor. That part number I gave you before is for a brand new unit, not a rebuilt unit. It has a warranty, and you don't have to send them your old distributor as a "core" so it's less hassle than buying a rebuilt unit.
Besides, there's only a $17 difference in price between new & rebuilt.
3. I understand the "getting all over the place". If you've never dealt with trying to solve problems like this before, it's always a learning curve. Best practice is to take it logically, step by step through each system, especially on older vehicles like ours. There is no substitute for good diagnosis so taking it in order is your best bet.
Cranks, turns over, no spark, even with the brand new coil, it has to be 1 of 3 things. Either the Pickup Coil generating weak or no signal, Igniter malfunctioning (yours is new so probably not), or no power to the ignition circuit. I assume you've checked your Engine Fuse? 15 AMP Blue, 2nd from bottom on bank of 4 fuses, under dash.
Reference: https://www.yotatech.com/forums/f131...iagram-297871/
4. The Import Direct Brand is owned by Standard Motor Products, and is the brand they use for their "Made in China" parts, which I see stamped on the coil. As far as Made in China parts go, that brand is decent. The O'Reilly listing for it says it has a limited lifetime warranty, and that's a good clue. Most "lower end" Made in China Ignition Coils are only have a 6 month to 1 year warranty.
If they (O'Reilly's) are willing to replace it if it fails for as long as you own your truck, the quality has to be good, because they surely do not want to contend with continual "free" replacements; that eats into their profits. Given that I'd say it's probably OK to use.
Once you get your truck running again, if it were me & just to be sure, I'd resistance test it again after getting it hot (engine up to full temp for at least 10 minutes). If there are any heat soak problems with the resistance then it will show up on an Ohm meter. In general though, I wouldn't be concerned with the quality of that coil, it's adequate IMO.
If the Pickup Coil is reading 180.5 Ohms cold then I would say it is your most likely culprit. These units only generate a voltage of 3-5 volts DC, so any excess resistance in it would drop that down to a point where the signal is too weak to trigger the Igniter/Ignition Module.
You're already up against the high end of the spec and as it get heated from engine heat, the resistance is only going to go up higher, weakening the signal further.
Answers to questions:
1. If it's the original distributor I say sure, go ahead and replace with new. If you don't know if it's original or not, just have a very close inspection of it and make a determination. Most likely it is original at 208K miles. You are likely to have wear to bearing, the shaft, weakened advance weight springs and possiblly even built up debris that can make the advance weights sticky & not move freely like they should. All of these things can affect run quality.
If you have a Volt/Ohm meter you can also test the Pickup Coil for voltage. Just hook the meter up the same way you did for the resistance test but put the meter on the 250 AC Volts Range. Crank the engine over & watch the meter.
The result will NOT be steady voltage as it generates AC (alternation current) voltage, so you will see the meter "pulse" numbers, if you see anything.
Again, it only puts out about 3 to 5 volts so you have to watch the "pulses" on the display carefully. At the least this test will tell you if it's putting out voltage or not.
2. The new distributor will have all the parts that you need pre-installed & calibrated, except for (usually*) the Rotor & Cap & Spark Plug Wires; you will usually* have to provide those.
*The pic on Rock Auto shows a Cap in place, so those parts may actually come with the brand new unit. I always assume I have to provide the extra parts I listed as I usually buy rebuilt units.
As a matter of routine, I check the Air Gap Spec I mentioned before installing, just to be sure it wasn't set on a Monday, if you know what I mean.
When it comes to older vehicles like ours, I've found that most part stores don't carry stock of parts, or even if they do or have to "special order" it, the prices are fairly high. Rock Auto doesn't have that problem, as they tap over 2 dozen different warehouses & suppliers to fill orders. Plus their operating overhead costs are much lower; e-commerce vs retail store, so they can offer much lower pricing. No I do not work for Rock Auto and I am not sponsored by them. :^) Please also note that the price you see does not include shipping charges, but even with those added in, the price is almost always lower than getting it from a parts store.
Last thing about that distributor. That part number I gave you before is for a brand new unit, not a rebuilt unit. It has a warranty, and you don't have to send them your old distributor as a "core" so it's less hassle than buying a rebuilt unit.
Besides, there's only a $17 difference in price between new & rebuilt.
3. I understand the "getting all over the place". If you've never dealt with trying to solve problems like this before, it's always a learning curve. Best practice is to take it logically, step by step through each system, especially on older vehicles like ours. There is no substitute for good diagnosis so taking it in order is your best bet.
Cranks, turns over, no spark, even with the brand new coil, it has to be 1 of 3 things. Either the Pickup Coil generating weak or no signal, Igniter malfunctioning (yours is new so probably not), or no power to the ignition circuit. I assume you've checked your Engine Fuse? 15 AMP Blue, 2nd from bottom on bank of 4 fuses, under dash.
Reference: https://www.yotatech.com/forums/f131...iagram-297871/
4. The Import Direct Brand is owned by Standard Motor Products, and is the brand they use for their "Made in China" parts, which I see stamped on the coil. As far as Made in China parts go, that brand is decent. The O'Reilly listing for it says it has a limited lifetime warranty, and that's a good clue. Most "lower end" Made in China Ignition Coils are only have a 6 month to 1 year warranty.
If they (O'Reilly's) are willing to replace it if it fails for as long as you own your truck, the quality has to be good, because they surely do not want to contend with continual "free" replacements; that eats into their profits. Given that I'd say it's probably OK to use.
Once you get your truck running again, if it were me & just to be sure, I'd resistance test it again after getting it hot (engine up to full temp for at least 10 minutes). If there are any heat soak problems with the resistance then it will show up on an Ohm meter. In general though, I wouldn't be concerned with the quality of that coil, it's adequate IMO.
Will do. I just thought it was kind of interesting how it also doesn't start when cold. I'll go ahead and replace the distributor. Let's see how it goes and I'll update the post. Appreciate all the info and help.
Quick update, just took the truck out on the freeway for a test drive after replacing the distributor. She ran fine! Purred like a kitten up those hills, LOL. I don't want to start celebrating too soon though. I'm going to give it a few more runs and make sure everything is in fact rock solid. I'll include a list of everything I replaced, in case anyone has similar issues. At the end, it ended up being the pickup coil in the distributor. I have 208k original miles on the truck so I went ahead and replaced the entire distributor as a precautionary measure. Thank you to everyone for all the help, responses and input.
Nice work! Check your timing (if you haven't already) & make sure it's set (5 degrees before Top Dead Center, completely warmed up & at idle speed) and get some fresh spark plugs in it and it may start purring like a tiger Spark plug gap is .032". Don't overtighten your plugs when you install them.
Apr 12, 2020 | 09:42 PM
Spark plug gap is .032". Don't overtighten your plugs when you install them.
