Where to start with MS and a sr20det engine - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 06-25-2008, 09:36 PM   #21
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You rock joe. One other thing, I did see the ignitor in the engine bay, it looks exactly like a miata one.

So for building the MS, using this link http://www.diyautotune.com/tech_arti...s_overview.htm

I should:

use the directions for the Distributor Based Ignition on a Megasquirt-I V3.0 Board

or

use the directions for the Direct Coil Control Distributorless Ignition on a Megasquirt-I V3.0 Board



I mean if the COPS work just like a 1.6 miata would, I dont need to add the VB921 circuits that are in the 2ed link, right?



Finally will I need to do any more mods to the bord for the tach input or the such?
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Old 06-26-2008, 12:51 AM   #22
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Interesting, I've never seen that link... Anyway, do neither of those.

If you wind up using a crankwheel (which I hugely recommend), then you'll build the VR input circuit as per the normal MS build directions, but wire two coil outputs exactly as per "Option 1: Spark Output to factory Miata ignitors" in this link: http://www.diyautotune.com/tech_arti...azda_miata.htm You'll have two trigger outs from the MS, and you'll pair the igniter's trigger inputs to those- coils 1 & 4 on the MS SparkA, 2 & 3 on SparkB. Actually, not exactly exactly, I suggest you use 330 ohm resistors instead of 1k.

If you are able to procure a 4/1 CAS, then you'll be able to do full sequential ignition and you'll have to build this circuit: http://www.msextra.com/manuals/Ignit...ual.htm#5Vpull Actually, I don't like that circuit as it's drawn- we'll come up with something a tad different for you perhaps.
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Old 06-26-2008, 01:17 AM   #23
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ok I think I understand what ill do now.

Get the 36-1 wheel

use the settings for a 4 cylinder engine that DIYautotune provides in my link above.

Mod the MS like a miata, using joes link

tap into the sr wireing harness similar to the miata

then all it would take is finding the right dewll times for the coils and im good to go!


Then I just need to work on values for the water temp sensor, id use a GM IAT sensor, OH


Joe, does it look like the SR fired the injectors like the miata? Thus no mods specifically need to be done to the MS for fuel.


And one more thing, where do you get a VE sensor at??
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Old 06-26-2008, 02:22 AM   #24
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ok I think I understand what ill do now.
Get the 36-1 wheel
use the settings for a 4 cylinder engine that DIYautotune provides in my link above.
Mod the MS like a miata, using joes link
tap into the sr wireing harness similar to the miata
then all it would take is finding the right dewll times for the coils and im good to go!
Sounds like a plan. If you have access to an oscilloscope it might be worth probing the lines between the ECU and the igniter just to double-check that they're 5v and not 12v, but I'm betting very strongly on 5v- it's a much more common standard on Japanese motors.
Joe, does it look like the SR fired the injectors like the miata? Thus no mods specifically need to be done to the MS for fuel.
Yeah, pretty much all injectors, even factory lo-z injectors, are triggered the same way. Put a solid +12 on one end, and switch them to ground through the ECU. You should use an ohmmeter to verify that they're hi-z (10 ohms or more) vs. lo-z (typically 1-4 ohms) before finalizing the MS build.
And one more thing, where do you get a VE sensor at?
Damn near any Ford. I'm using one from a '95 Escort 1.9, but you can also get 'em off T-birds, Tauruses, etc. Electrically they're all the same, but they differ greatly in physical packaging.
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Old 06-26-2008, 07:32 AM   #25
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Alright! and Joe,

Using this diagram http://www.scribd.com/word/full/1033...u6ienji9k9adum

I will have to tie together pins 101+103, 110+112, 1+8, 2+9, correct? those would be what I would then connect the fuel and spark outputs to from the MS

Also, do I have to worry about pin 105?

And how would I tackle the MS ground connections?

So I could just take out the whole ecu, and have MS run spark, fuel, fans, idle air control, and be good?

Or should I just leave the stock ecu, and run it piggyback style, just with the wires for the injectors and coils disconnected from the ecu? Or would this cause the ECU to freak out?
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Old 06-26-2008, 12:55 PM   #26
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I'm afraid that link is no workee for me.
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Old 06-26-2008, 01:24 PM   #27
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Old 06-26-2008, 01:49 PM   #28
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I will have to tie together pins 101+103, 110+112, 1+8, 2+9, correct? those would be what I would then connect the fuel and spark outputs to from the MS
Hmm. That Wolf document does not agree with the two documents I'm looking at- the image I posted, and the PDF of the "Sylvia S14 Europe Spec ECU Wiring, SR20DET" document. This is why we need an actual factory wiring diagram specifically from your donor engine.

Ok, assuming that the two documents I refer to are correct (which I don't know to be true) and that the new motor has the same firing order as a Miata, then 101+103 would be one injector channel, 110+112 would be the other injector channel.

1+12 at the ECU would get you 5+1 at the igniter, and this would be coils 1 & 4, to SparkA of the MS. 2+11 at the ECU gets you 4+2 at the igniter, for coils 2 & 3 to Spark B of the MS.

Also, do I have to worry about pin 105?
Pin 105 in the Wolf document indicates fuel pump speed. Frankly, I have no idea how the fuel pump in your car is wired, the different documents I come across differ in this regard. If it's got the variable-speed pump system, you'll need to bypass that and wire the pump to simply switch on when commanded by the MS. That'll be a relay. If your fuel pump is the more conventional style which is simply on or off, then you can just connect the existing fuel pump relay to the MS.
And how would I tackle the MS ground connections?
By connecting them to ground.



There are so many uncertainties here that you're probably going to end up doing some trial and error research with a multimeter and a flashlight. Again, I cannot stress enough the importance of finding the correct and actual documentation for whetever combination of engine harness and ECU harness your particular car has.
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Old 06-26-2008, 03:02 PM   #29
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Sounds good, he should be getting the car soon, then I can take the ECU and fine exactly what connections are what, and ill update the thread.

Quote:
Originally Posted by Joe Perez View Post



There are so many uncertainties here that you're probably going to end up doing some trial and error research with a multimeter and a flashlight. Again, I cannot stress enough the importance of finding the correct and actual documentation for whetever combination of engine harness and ECU harness your particular car has.
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Old 06-26-2008, 05:39 PM   #30
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JOE, here is the exact wireing diagram:

http://jimwolftechnology.com/wolfpdf...%20DIAGRAM.pdf

and here is a english pin out diagram http://www.plxdevices.com/ECUDatabas...0DET_91_95.pdf
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Old 06-26-2008, 09:24 PM   #31
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By that wireing diagram, just beacuse each coil has its own ecu pin, that doesent mean it cant be used in a wasted spark mode, just tie the wires together right?
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