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Hey Everyone, I am currently swapping a 85 5MGE in place of my 82 5MGE that was in my 87 4runner. the 82 was just tired and needing a rebuild so i managed to pick up a 85 5MGE that had everything included except the ignitor and coil. I have tried to wire in the ignitor from the 82 to the 85 engine and ECU. I am not getting any spark and after some searching on the subject have come to realize that the 82 ignitor will not work with the 85.

So my question is as there are not any local wrecking yards with a 85 supra or cressy, can I use an ignitor from any other vehicles. eg. the stock 87 4runner coil or a celica or camry or something. or will the ignitor from a 86 7MGE work as there is one of those locally.

thanks
 

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I've got an 83 ignitor and coil pack, but that won't work......:
Copied form the Celica Supra site:

82 is 82, unique.

83 to mid 84 ignitor was very likely to fail. My 84 failed on me in 92 in Newport RI.

Late 84-86 ignitor is great, and works with 83+ (83 ignitor only works with 83)

I've ran my 83 on an 84 ignitor. Ran fine. But an 84 would not run on an 83.
 

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Discussion Starter #4
I've got an 83 ignitor and coil pack, but that won't work......:
Copied form the Celica Supra site:

82 is 82, unique.

83 to mid 84 ignitor was very likely to fail. My 84 failed on me in 92 in Newport RI.

Late 84-86 ignitor is great, and works with 83+ (83 ignitor only works with 83)

I've ran my 83 on an 84 ignitor. Ran fine. But an 84 would not run on an 83.
Yeah thats what I was reading, so i know that in 86 they made the mk2 and the mk3. Does anyone know if i can use the ignitor from an 86 MK3 with a 7MGE or do I have to stick with 5MGE ignitors
 

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Good choice on upgrading from the 82 low compression engine to the 85 high compression engine. That will probably be a 20hp difference right there. Did you also swap in the 85 ECU and engine wire harness/sensors? That would get you the full benefit of the 85 engine.

I'd ditch the 82 stuff anyway, as it is year specific and spare parts are hard to find. Make an 82 owner happy and sell them as spares! I've had an 83 and 84 Supra and never had any problem with the ignitors. Last year I had the ignitor suddenly go on the two-tone, but I had plenty of good spares and got it going again the next day. Since the 7MGE is an 86 (must be a MK3 Supra), I'd guess that ignitor is very close, if not the same as the 85 so I'd try that. Cressida ignitors (5MGE engine) will also work if you repin the correct plugs to it.
 

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Discussion Starter #6
Good choice on upgrading from the 82 low compression engine to the 85 high compression engine. That will probably be a 20hp difference right there. Did you also swap in the 85 ECU and engine wire harness/sensors? That would get you the full benefit of the 85 engine.

I'd ditch the 82 stuff anyway, as it is year specific and spare parts are hard to find. Make an 82 owner happy and sell them as spares! I've had an 83 and 84 Supra and never had any problem with the ignitors. Last year I had the ignitor suddenly go on the two-tone, but I had plenty of good spares and got it going again the next day. Since the 7MGE is an 86 (must be a MK3 Supra), I'd guess that ignitor is very close, if not the same as the 85 so I'd try that. Cressida ignitors (5MGE engine) will also work if you repin the correct plugs to it.
yes I cant wait to hear this thing start, that tired old 82 was smoking every color of the rainbow pretty much. I have upgraded everything to the 85 except the ignitor and coil. The engine, engine harness, ECU and AFM have all been swapped. I figuered i would try to use the 82 ignitor as i had it in the truck already and i knew it worked. I am not getting spark while cranking though... only when i let off of the starter do i get a spark from the coil. I have gone over all my wiring and it should run... so the ignitor is where im at right now.

any one else with any information is welcome to lend some insight here.

Thanks
 

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The igniter is just a high power switch controlled by the very low power switch / sensor inside the distributor and in later systems, through the ECU. The fact that you get a spark when the key returns from the start position tells you two things: 1) you have the proper power and ground to the igniter in start but no switching and, 2) no power in run or most likely, power to both igniter terminals and no ground essentially disabling it.
I don't know all the specifics of the 82 but with the timing being manual vacuum advance, it must be wired differently than later ECU controlled ignitions. Later systems control power to the ignition as well as timing based on temp, knock sensor, TPS, etc. Earlier ones likely have a much simpler system just supplying power and conflict with the later ECU. I'm thinking that both systems send a signal to the igniter to fire but the later one has a longer control loop through the ECU and this is where the igniter wiring differs. I would guess that it's the igniter trigger (ground) that's at a constant 12V that's causing your problem.
Most people think a spark is generated when power is applied but it's the opposite. When power is removed, the collapsing field in the coil generates the voltage spike to fire the plugs. Virtually all fully electronic systems (of all kinds) switch ground on to enable something where older analog systems virtually always work the opposite. The end result being that something with 12V on both terminals is disabled which is what I suspect you now have with the 82 igniter vs. the old way. You should be fine with a later model igniter. Let's hope that no damage has been done otherwise.
 

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Discussion Starter #8
The igniter is just a high power switch controlled by the very low power switch / sensor inside the distributor and in later systems, through the ECU. The fact that you get a spark when the key returns from the start position tells you two things: 1) you have the proper power and ground to the igniter in start but no switching and, 2) no power in run or most likely, power to both igniter terminals and no ground essentially disabling it.
I don't know all the specifics of the 82 but with the timing being manual vacuum advance, it must be wired differently than later ECU controlled ignitions. Later systems control power to the ignition as well as timing based on temp, knock sensor, TPS, etc. Earlier ones likely have a much simpler system just supplying power and conflict with the later ECU. I'm thinking that both systems send a signal to the igniter to fire but the later one has a longer control loop through the ECU and this is where the igniter wiring differs. I would guess that it's the igniter trigger (ground) that's at a constant 12V that's causing your problem.
Most people think a spark is generated when power is applied but it's the opposite. When power is removed, the collapsing field in the coil generates the voltage spike to fire the plugs. Virtually all fully electronic systems (of all kinds) switch ground on to enable something where older analog systems virtually always work the opposite. The end result being that something with 12V on both terminals is disabled which is what I suspect you now have with the 82 igniter vs. the old way. You should be fine with a later model igniter. Let's hope that no damage has been done otherwise.
Wow Thanks Ray, that was alot of info right there that made alot of sense. that seems to be exactly what is happening... the trsm for the 85 supra says the between IGT-E1 I should get 0.7-1.0 volts when cranking or idiling.... I get over 6 volts when testing this.

I am now on the hunt for a 85 supra coil and ignitor.

Would one from an 84 cressy work? I know i might have to change some plugs but question is is the 84 cressy more like a 83 supra? as cressies were usually a year behind the supra.

thanks for the help so far.
 

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Discussion Starter #9
well thanks to all of you and especially ray85p, I got a proper 85 one that was so graciously given to me on a trade and put it in and voila she fired right up and purred.

Thank you all
 

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well thanks to all of you and especially ray85p, I got a proper 85 one that was so graciously given to me on a trade and put it in and voila she fired right up and purred.

Thank you all
Glad to hear the coil and igniter worked for you.
Anybody need an 82 igniter...? haha
Dave
 

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Since I'm the source of the ignitor summary posted above by Yotafan (who I've met 17 months ago), figured I should expand a bit from a parts perspective, not an electronics perspective I haven't taken the igniters apart, but someone in FL or GA did a few years back and I remember. I've had 2 igniters fail on me, so I have learned from problems.

In 1992 a Toyota replacement ignitor was over $400 (I paid that)
~ 2008-2011 Toyota had a replacement ignitor for the non-turbo 5M/6M/7M for ~$140 list price. No longer in stock - but was for all 3 engines

Cross-reference says the 82 is unique. It is.
Cross-reference says the 83 is unique. It is, but the engine will work with a later ingitor, but 83 ignitor will not work with 84+ (I tested this)
84-88 (non-Turbo, to include Cressidas) minor changes, nothing major
88+ NT Supras I do not know

Cressida ignitors are similar, but have differert bases. An impact screwdriver is often required to loosen the connection.
 

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Since I'm the source of the ignitor summary posted above by Yotafan (who I've met 17 months ago), figured I should expand a bit from a parts perspective, not an electronics perspective I haven't taken the igniters apart, but someone in FL or GA did a few years back and I remember. I've had 2 igniters fail on me, so I have learned from problems.

In 1992 a Toyota replacement ignitor was over $400 (I paid that)
~ 2008-2011 Toyota had a replacement ignitor for the non-turbo 5M/6M/7M for ~$140 list price. No longer in stock - but was for all 3 engines

Cross-reference says the 82 is unique. It is.
Cross-reference says the 83 is unique. It is, but the engine will work with a later ingitor, but 83 ignitor will not work with 84+ (I tested this)
84-88 (non-Turbo, to include Cressidas) minor changes, nothing major
88+ NT Supras I do not know

Cressida ignitors are similar, but have differert bases. An impact screwdriver is often required to loosen the connection.



has this person figured out why these go out all the time?
 

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That would depend on what's inside the ignitor module. It could be just a simple transistor, or it could have some other "level-shifting" and isolation electronics inside it to interface it with the ECU.

In the old days, we called them "Transistorized Ignitions", which basically meant that instead of having the points switch the 12 Volts to the primary of the coil, they now used a power transistor to do the heavy switching, typically in an assembly called an "amplifier", with the points either triggering the Base of the transistor, or being entirely replaced with an optical or magnetic triggering arrangement.

In later days, the ECU was used to directly control the transistor, receiving it's trigger signal from the distributor or a crank trigger arrangement.

An interim solution would have been something like the GM "HEI" distributor, which had the trigger mechanism, switching electronics, and coil all integrated into the cap.

These days we have "Coil on Plug" systems, where the ECU directly fires the coil, and we don't have to worry about pesky caps and rotors wearing out.

But I digress.....

The thing that would be most likely to fail in an ignitor module would be either the switching transistor, or the protection ("Flyback" or "Free Wheeling") diode. The primary of the coil will "kick" back with anywhere from 300 to 500 Volts when it's switched, and back in the early 1980's, making transistors that could withstand this voltage was not easy to do economically, which partially explains the $400 cost of the ignitor. There's usually a protection diode in there to absorb the inductive kick and protect the transistor, and probably a few other parts as well. My first wife's 1984 Tercel had the ignitor go belly up on us, and when I called the dealer for a price, I about fell over, as it was around $300! He then told me that it was covered by warranty, but we'd have to have the car towed in so they could do the repairs.

I've got the official Toyota shop manuals and wiring diagrams for 1984 and 1985, but IIRC, all they show for the ignitor is a box on the diagrams with the wiring connections.

If somebody would be willing to send me a dead ignitor (I'll even pay the postage!), I'd be happy to do an autopsy on it. I suspect they're potted in epoxy, which will make getting to the PC board and parts inside a pain, but if we know what's inside, we could possibly develop a fix, or reverse engineer a replacement unit.

Are there aftermarket units available? I've seen several cars on CL that say they have an MSD ignition. Does this replace the ignitor, or run in conjunction with it?

Guess I'll have to really start pouring over my Supra shop manuals to learn all the correct terms, where modules are located, and start memorizing the electrical diagrams!

Jim
 

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Jesus Dr. Jim, if we have the same birthday, I'm going to think Mom gave one of us away at birth. It would be very easy to understand why. Nice digressing by the way! You probably remember the strange looks on peoples faces when they found out that early transistorized ignitions still had points AND that they lasted (nearly) forever??? We're not old yet. We're just calling them the old days, right?
I'll try and dig out the one that failed on my 85p not that long after the warranty expired. I still recall the feeling that my knees were about to buckle even at my then 25% off dealer price. If the epoxy potting gives me the finger like the diodes on the armature of a brushless generator did recently, I'll gladly send it on to you for something way beyond a BF hammer and chisel or whatever it takes to make it give up its secrets.
Well, I actually had a name for that hammer until then. It used to be my "Doesn't take No for an Answer" hammer. I've lost my respect for it and I'm sure it thinks I've gotten old and tired. This is why it might just be best to send it to you for autopsy. Otherwise, I doubt either of us could do a proper autopsy on the dust and shrapnel anything will be after my next use of that hammer beyond "It (must have / obviously) died a tragic death".
I'm sure that you're right and that there just might be a current replacement for whatever fails on the old ones. I'm actually surprised that I never dug into it back then although I was traveling for work nearly all the time. It's just that its replacement has lasted to this day. I must have known that it was destined to be useful in the future, however. I just never thought I'd have lived that long. PM me your address and I'll send you a package. Ignore the ticking sound when it arrives. It's just the detonator from the nuclear bomb any kid of mine would have made for kindergarten show and tell. No actual bomb material will be included! Just kidding.
You know, it would be even more useful to know what the replacement units have inside them. However, it won't be as easy to find a failed one. Perhaps someone has one or could grab a physically damaged one at a P-N-P for your analysis as well.
I'm looking forward to your analysis of "The Problem" as I'm sure we all are. Pictures of the tragedy and the miracle recovery would be a nice touch. Hint hint... Good luck.
 

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HAH!

My Dad's name was Ray, so maybe there's some kind of Cosmic Connection there.

I've done things like this before. Getting the potting compound out depends on if it's the really hard kind, or the softer rubbery kind.

It's been so long since I considered myself an Active Gear Head, that it feels great to have all this old knowledge come flooding back.

I'll really start pouring over the electrical diagrams and try and get a handle on who's doing what to whom. This stuff 'aint Rocket Surgery, and I think it should be pretty easy to come up with a replacement ignitor that doesn't cost an arm, leg, and left testicle.

I was doing some searching after I made the post, and the ignitor mounts under the coil, and the whole shebang gets screwed down on the driver's side front inner fender, right?

Can hardly wait until I get my hands on a car, and start poking in around the electricals with my good old Tektronix oscilloscope to see if I can figure out how it all plays together.

At least in cars this age, all the goodies are in separate boxes/assemblies, and if you can look at the gozintas and comesouttas, you can generally figure out what and how the box is doing it's thing!

Jim
 

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Heat kills electronics. Well, heat and time. I had an ignitor fail on me last summer. Since then I've learned more about them.

The circuit board inside of the "black box" inside of the ignitor casing is coated in a clear gel, not epoxy. When I removed the black box from the case, I found a white heat-transferring grease under it (to conduct heat from the circuit board to the case as a heat sink). I think this grease dries up over time, allowing the ignitor to overheat and die.

Solution - take apart ignitor and smear some more heat-transfer grease in there. It can be bought at computer equipment stores and Radio Shack. For an extra measure, relocate the ignitor out of the engine bay and into an air stream (like behind the grill) for better cooling.

My solutions are based on how Chrysler handled it's fan controller relay box on it's minivans. It went from being mounted on the inside of the frame rail, to on top of the frame rail in the incoming air to the air filter box, to in the middle of the front bumper behind the grill with a huge aluminum heat sink attached to it. It also uses the special grease between the unit and the frame, to dump heat. Figure we can apply the same engineering to our cars. :)
 

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That's good about the rubber type coating. I'd suspect it's an RTV type compound, which isn't too difficult to remove.

Yes, the white grease is heat-sink compound, and aids in the conduction of heat from the components to the case, where it can be carried away by either conduction (through its mounting plate) or convection, which is the air stream you mention.

The old grease should be removed before applying new. I use Birchwood-Casey "Gun Scrubber" solvent because I have it, but a "Brake Clean" type of solvent would work as well.

Generally speaking, you want to use the *minimum* amount of heat-transfer compound. It's most definitely NOT a case where "If Some Is Good, More Is Better"! Too much of the compound will prevent the board from seating properly in the case, with good metal-to-metal contact. The metal-to-metal contact transfers heat MUCH more efficiently than having the board forced away from the metal can by 1/16" of heat-sink grease!

And moving it out of the engine compartment, or into a stream of cool air, can do nothing but help with the thermal load.

Jim
 

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Since I'm the source of the ignitor summary posted above by Yotafan (who I've met 17 months ago), figured I should expand a bit from a parts perspective, not an electronics perspective I haven't taken the igniters apart, but someone in FL or GA did a few years back and I remember. I've had 2 igniters fail on me, so I have learned from problems.

In 1992 a Toyota replacement ignitor was over $400 (I paid that)
~ 2008-2011 Toyota had a replacement ignitor for the non-turbo 5M/6M/7M for ~$140 list price. No longer in stock - but was for all 3 engines

Cross-reference says the 82 is unique. It is.
Cross-reference says the 83 is unique. It is, but the engine will work with a later ingitor, but 83 ignitor will not work with 84+ (I tested this)
84-88 (non-Turbo, to include Cressidas) minor changes, nothing major
88+ NT Supras I do not know

Cressida ignitors are similar, but have differert bases. An impact screwdriver is often required to loosen the connection.

Actually we met about 6 months ago at Aarons 10th anniversary Chimp meet. I never even owned a Supra before June 2012.
 
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