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Wasted spark questions

J

JimmyMelbs

New member
Joined
Jul 19, 2015
Hi guys,
I have a 89 740t wagon which has been converted to lh2.4 and need some assistance

I've installed the wasted spark board in my ez, I have it ready to hook up to a 960 ignition module and Bosch 2x2 coils.

I just need help figuring out what to do with existing coil and power stage in the engine bay.
I like being tidy so if I don't need them can I disconnected the existing coil and ignitor?

Can someone who has more information on this than me please shed some light here.

Obviously I still need a tach output.

Thanks
James
 
JimmyMelbs said:
I just need help figuring out what to do with existing coil and power stage in the engine bay.
I like being tidy so if I don't need them can I disconnected the existing coil and ignitor?
Click to expand...

Yes.

You can probably use the tach output of your new power stage (depending on model).
 
According to the wasted spark thread unless running the Miata ignitor with built in ignitor you need the old coil or a 'dummy coil' with an opened relay for tacho .
I'd prefer to do away with old power stage / ignitor and old coil.
Can I do this and if so where do I put the old wiring ?
 
I left the stock ignitor in place since it's already buried out of sight.

Currently my coil is unplugged but still in the bay. Also, not really in the way.

I'm using a dummy relay for my tach signal just fine, followed the many diagrams in the thread. I didn't gut it as the terminals you use aren't the ones connected to the magnet, hence no buzzing.

Once you're confident with your setup, just unplug and tuck the wires away.
 
nitroboie said:
I left the stock ignitor in place since it's already buried out of sight.

Currently my coil is unplugged but still in the bay. Also, not really in the way.

I'm using a dummy relay for my tach signal just fine, followed the many diagrams in the thread. I didn't gut it as the terminals you use aren't the ones connected to the magnet, hence no buzzing.

Once you're confident with your setup, just unplug and tuck the wires away.
Click to expand...

+1, dummy coil where the tach used to be. Tempted to attach it to the cluster under the dash.

Alfa/Bosch 2 channel powerstage for the Bosch 2x2 coil, stock one left in place for the tach.

Been running WS since 2011, apart from some software issues on the very early stuff it has been very stable. BTI board, Bosch coil, good stuff. Do use the right plugs - ran plugs without resistor and that wreaked havoc with stuff, interference and stuff. Still planning to remove the old spark dizzy. Funny looks at the inspection tho.
 
JW240 said:
+1, dummy coil where the tach used to be. Tempted to attach it to the cluster under the dash.

Alfa/Bosch 2 channel powerstage for the Bosch 2x2 coil, stock one left in place for the tach.

Been running WS since 2011, apart from some software issues on the very early stuff it has been very stable. BTI board, Bosch coil, good stuff. Do use the right plugs - ran plugs without resistor and that wreaked havoc with stuff, interference and stuff. Still planning to remove the old spark dizzy. Funny looks at the inspection tho.
Click to expand...

Oh, really? Run resistor plugs, even with suppressor core wires?
 
Thanks for the feedback guys.
Did you reuse wiring from old power stage to hook the new one up or take power and ground from elsewhere?
 
JimmyMelbs said:
Thanks for the feedback guys.
Did you reuse wiring from old power stage to hook the new one up or take power and ground from elsewhere?
Click to expand...

I left the stock wiring in place and created my own harness. I used a male connector to plug into the stock blue power wire that connects to the coil. I ground directly on the valve cover. My powerstage is mounted on the valve cover using the BTI bracket.
 
nitroboie said:
I left the stock wiring in place and created my own harness. I used a male connector to plug into the stock blue power wire that connects to the coil. I ground directly on the valve cover. My powerstage is mounted on the valve cover using the BTI bracket.
Click to expand...

I think I've seen your build somewhere.
I'm mounting my coil like duder did in the location the 240 distributor would sit as there's a hole there for a bracket. I've pulled old ignitor off heatsink and attached the new 960 one.
Now to cut into existing power and ground wires from old connector and pin up the new one along with the wires from the board for the coils and I should be good.
Thanks !
 
Okay all wired up ready to go.
Cut the power and ground wire from the original power stage connector and repinned ground to centre of 2x2 coil and power to pin 4 I think it was on new connector.
Will this work?
Still buttoning everything else up before first start.
I hope doing this will maintain tach function?
Is the old coil still getting power from the battery now or since i pulled power and ground from connector would this affect it?
 
I see some of you guys are unplugging your coil wire.... BE CAREFUL DOING THIS!!! My plastic connector was broken off of mine, I had left mine unplugged and it had worked its way against the strut tower and grounded. There is no fuse to blow. (atleast mine didn't have one) It cooked all of the insulation off the coil wire and would have made it all the way back to my ignition switch if I had not shut if off when I did. I managed to dig out all the cooked wire, I didn't need it anyways and patch up other wire it damaged. I got pretty lucky that my entire car didn't go up. It's pretty easy to make that dummy coil from an old relay. If you don't do that, then cover the ends of those really well. Don't be a dummy like me :lol:

Also for some reason I had to leave in my old ignition module in place for my tach signal. I used the J702t ignitor.
 
I also had to leave my old module in place when I used the j702 miata one...I figured mine was a dud from the junkyard....

Using the j702 I have to keep the wire going to the coil connected along with the old module dangling down next to the battery to retain my tach function. My brother just used the red/white wire going to the old module for his tach. I didnt get so lucky
 
Thanks for the replies.
I'm using the Bosch ignitor .
Do I just unplug the coil wire and wire it to the new connector ? Ground to battery - or chassis?
Where do I plug the relay in?
Lastly I've upgraded to an efan. I need switched 12v for this I was going to run off the coil.
Since I'm taking the power lead off that, where else can I get switched 12v from engine bay or do I need to wire it up to something in the cabin?
Thanks everyone!
 
The first (and arguably easier) method works if you have left the stock power stage and wiring intact. Simply move any wires currently connected to the stock coil's two spade terminals to the "85" and "86" terminals of an automotive relay. To keep the relay from clicking you should open the body of the relay and remove the contactor assembly.


I copied and pasted from this: https://forums.turbobricks.com/showthread.php?t=246170
 
littlesnides said:
The first (and arguably easier) method works if you have left the stock power stage and wiring intact. Simply move any wires currently connected to the stock coil's two spade terminals to the "85" and "86" terminals of an automotive relay. To keep the relay from clicking you should open the body of the relay and remove the contactor assembly.
.

I copied and pasted from this: https://forums.turbobricks.com/showthread.php?t=246170
Click to expand...


Thanks for that but I have 4 or 5 things connected to my stock coil so I'm not sure what they all are
 
JW240 said:
I'm running 500 Ohm/m leads (stainless steel wound ferrite core ishv stuff), less suppression than the usual leads. Denso plugs.
Click to expand...

Hi Jan Willem, where did you buy them, do you have a link?
As JW stated before running without problems for 4 years now.
 
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