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DIY COP Kit with Denso/Honda coils

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JayRome

15+ Year Contributor
233
147
Dec 12, 2008
Victoria, Australia
I have had a few people ask me how I got my COP kits to work on factory VR4 ECU....

So here is a quick run down on how to make your own... Do this at your own risk, not my issue if you blow something up!...

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Using Toyota Denso 4 wire coils (or Honda 3 wire) which have built in ignitor's.. Or even factory Evo 4-9 coils...

Coils that i was using: Denso 90919-02240
Mounting plate for early model 4G63: Custom made with 6mm alloy plate

Borrowed off Evolution.net Evo EVO4-9
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Modified for early models: VR4/EVO1-3
All the wiring can be tapped directly from you factory Ignitor located on the side of your Intake maifold.
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Now using the above diagram (in the photo) wire the coils to your factory Ignitor pack via below Diagram (borrowed from Microtech Aust diagrams) pending on which Ignitor your car comes with, you can usually tell by how many wires are going to your stock coil packs: (might have to switch blue and yellow around, just like mixing up your ignition leads, Also ignore the written color codes from the original print)
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Now, after the above mod's you will notice that your RPM gauge no longer works but your car starts and runs..
Here is how you make that work with very little parts:

DO NOT cut off your stock Ignitor pack, leave it where it is and do this:

Pending on which version Ignitor pack you have (which you should have figured out by now from above wiring), you will need a dummy load. I have tried a few things, best so far is a small 12V relay which should be relatively cheap and easy to get: (you will need 2 of these)
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Wire them in place of the factory "coil" output from the stock ignitor:
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Now the 4pin coil packs should be fine with their "Tach Interface" unit working with the smaller load (Red and White wire are connect to the output of the Ignitor which goes to the coils, Yellow goes straight to the Tachometer which turns to White wire later on)
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I have found that the 3 wire coil set up (later model), the Tacho still wont work as they merged the "tacho interface" and "ignitor" into the same housing and it will only work with a larger load (a coil). So you might have to make your own "tacho interface" with a few simple parts (in the diagram below) remember to cut the "tach" wire from the Ignitor and route it to your DIY tach interface: (Diagram borrowed off the MegaSquirt guys)
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I have been writing this in between work loads, so I may have missed a few things, will update shortly...


Feel free to discuss and or add your thoughts..
 
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That looks pretty well documented, good job!

Have you tried inductors, instead of the relay, as the dummy load? A large enough value should get it to work for both types of ignitor. That way you save the trouble of cutting the tach wire at the ignitor. Then you could actually get all the signals you need, right at the coil plug.
 
I don't see any dwell compensation circuitry here. Is the dwell in your vr4 ecu just happening to get close enough to the dwell for the coils so you don't overrun the coils? Have you done any load testing to make sure the coils don't die prematurely, fail temporarily, or anything similar?
 
That looks pretty well documented, good job!

Have you tried inductors, instead of the relay, as the dummy load? A large enough value should get it to work for both types of ignitor. That way you save the trouble of cutting the tach wire at the ignitor. Then you could actually get all the signals you need, right at the coil plug.

I did at one stage, i forgot if it worked or not (i don't see why not), but the tiny relay's were just easier to hide and to obtain (mine came off an old alarm circuit board that was lying around). Won't be able to hear a ticking over the injectors anyways and almost no heat build up.


I don't see any dwell compensation circuitry here. Is the dwell in your vr4 ecu just happening to get close enough to the dwell for the coils so you don't overrun the coils? Have you done any load testing to make sure the coils don't die prematurely, fail temporarily, or anything similar?

good pick up, dwell on factory style ignition should be around 3.5ms (someone correct me if i'm wrong here)

Dwell on the Toyota coils should be as follows (According to the Motec guys down here):
8V 6.3 ms
9V 5.3 ms
10V 4.4 ms
11V 3.8 ms
12V 3.2 ms
13V 2.7 ms
14V 2.4 ms
15V 2.2 ms

Havent had an issue so far with the junk yard coils dying (although I know of a few Evo4-9 guys that have killed a coil with their 600HP-ATW daily drivin cars), both my cars have toyota coils (VR4 Daily) and factory evo4-9 coils (ZR4 weekender) for over 3 years without a hitch so far. Have tested some Chinese ebay units on other cars and they worked fine as well (surprisingly).

Although honestly, upgrading to a cop kit is usually only really needed after 450-500bhp, I just made a few test kits to see if they would actually work on old factory ECU..
 
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When you buy the plug and play COP kits from SparkTech, is there the issue with tach not working without a rewire?

Just curious for future reference.
 
I did at one stage, i forgot if it worked or not (i don't see why not), but the tiny relay's were just easier to hide and to obtain (mine came off an old alarm circuit board that was lying around). Won't be able to hear a ticking over the injectors anyways and almost no heat build up.

A larger relay MIGHT have a large enough inductance to work, as long as it doesn't have the protection diode built in. I don't recall, it has been years since I messed with that.


good pick up, dwell on factory style ignition should be around 3.5ms (someone correct me if i'm wrong here)

The dwell measurements I took on my 2G were in the 4-6mS range. It varies with voltage, and also with RPM to some extent.

Although honestly, upgrading to a cop kit is usually only really needed after 450-500bhp, I just made a few test kits to see if they would actually work on old factory ECU..

Most COP kit are a downgrade from the stock system, without a proper CDI to drive them. The dwell time is matched to the stock coils.

I thought about pointing out the dwell issues, but I have been telling people about that for 15 years, and people seem to insist on COPs. So now I just try to help them make it plug in, so when they decide to go back to stock it isn't as hard to do :)
 
Spark tech pnp units use the oem ptu which generates the tach signal.

For this to work, you generally have to put something into the harness to create the feedback to the PTU like the way he did with the relay. Sparktech may build it into the harness, just like the ARC-2 has. If you look at what he has done here, he should be able to make it plug n play with the tach working just the same way.
 
A larger relay MIGHT have a large enough inductance to work, as long as it doesn't have the protection diode built in. I don't recall, it has been years since I messed with that.




The dwell measurements I took on my 2G were in the 4-6mS range. It varies with voltage, and also with RPM to some extent.



Most COP kit are a downgrade from the stock system, without a proper CDI to drive them. The dwell time is matched to the stock coils.

I thought about pointing out the dwell issues, but I have been telling people about that for 15 years, and people seem to insist on COPs. So now I just try to help them make it plug in, so when they decide to go back to stock it isn't as hard to do :)

I have warned people about the Dwell and tried to explain how its works and what it does.. although some still want to install the COP kit so hence the above post.. I'm only using it as i'm using as I have an EVO8 head on a 6Bolt Block. I do find the Evo4-9 coils an upgrade to original VR4 coils when revving to 8000RPM (and i dont have the space for the original coils), other wise on stock engines, stock coils are fine...
 
Hi guys, I ask for help. I have set Toyota coils (1nz/2nz)
I can't resolve an issue with the tachometer, my e39a of the first releases
With "ecu" there is a signal 0.40-0.50v etc.
With "power unit" 0.04-0.05 etc.
I have bought the relay 30a 12v but they naturally don't work at such small voltage.
Exit about the relay or an exit later with "taho interface" - an identical voltage
My "power unit" J122 (MD125840)
Acquaintances on eclipse have advised the scheme via "diodes"
Two diodes in one-the resistor-the transistor. Too doesn't work.
"power unit" and the instrument panel - a different signal in a galant and eclipse seem to me
At short-term connection of a conclusion to the current dashboard 12+v - the arrow jumps. My assumptions - there isn't enough voltage
 
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Get the denso coils that have a tach output, and wire one from each bank (1/4 and 2/3) together to the rpm input.
 
I correctly understand, to connect a signal of the IGF 1 and 2 cylinder for example. Via "diodes" (MegaSquirt scheme)? Or to do the same system with the relay and "tacho interface"?
 
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If I recall correctly, some of those IGF outputs produce a small analog voltage that isn't going to trigger a tach by itself. It goes back to the ECU for monitoring the spark.

Instead of wiring into the IGF, you might want to try using the signal wires that go from the ECU to the coils. You just need to make sure you are careful to not affect that signal
 
The only thing I can verify here is on a 95 DSM ECU if you use the Denso 90919-02265 coil you can wire the tach outputs, one from each bank (1/4 and 2/3) directly to the RPM input of the ECU, completely eliminating the tach circuitry of the PTU. Can't speak to any other coils because I simply haven't used any others. Take from that what you will, not sure if it helps your Galant or not.
 
Hi guys, I ask for help. I have set Toyota coils (1nz/2nz)
I can't resolve an issue with the tachometer, my e39a of the first releases
With "ecu" there is a signal 0.40-0.50v etc.
With "power unit" 0.04-0.05 etc.
I have bought the relay 30a 12v but they naturally don't work at such small voltage.
Exit about the relay or an exit later with "taho interface" - an identical voltage
My "power unit" J122 (MD125840)
Acquaintances on eclipse have advised the scheme via "diodes"
Two diodes in one-the resistor-the transistor. Too doesn't work.
"power unit" and the instrument panel - a different signal in a galant and eclipse seem to me
At short-term connection of a conclusion to the current dashboard 12+v - the arrow jumps. My assumptions - there isn't enough voltage


Just to confirm, your car runs fine yes?

Can you take a photo of your current set up for me..
 
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For the present day the current issue of the tachometer remains open.
I was told that my "readings" through the multimeter are not true, we must look at the oscilloscope.
Me were advised to take one ignition signal and connect it to the dashboard. Conduct a new wire from ecu to pin in the dashboard. If it does not work, then take the injector signal.
There is no time and an opportunity now to try.
Honestly, I can not correctly translate your advice and advice to overseas users who help me, so I'm looking for more solutions.
 
okay... can you take a photo of the ignitor pack? and how many pins?

apply this wiring diagram.. it should get it working again, its fairly easy to understand..


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It it doesnt work, you can try using a MD149768 J722T, which is what i use in my builds..
 
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