So i think i have have found out why it was impossible to get a good idle on my MS 1 1990 Miata with just 70k miles and there was no tachometer reading

i think i burnt up my ignitor (Ignition control module) i was trying to get my idle right and i was trying everything VE table adjustment ignition adjustments idle set screw ect.but i could not get it to idle smooth without anydropping in Revs

i felt my ignitor and it was extremely hot so i began to runs some test i discovered using this forum and others

The diagnostics port B+ to ig- with a 1k ohm 1/4 watt resistor this did help for a few moments (i think) as there was no drop in revs for about 45 seconds but then it dropped and started acting weird .

I then read on the internet that you can try and fault find an ignition control unit by cooling it down and see if it resolves any issues .it worked and the car idled like a champ.

so with all this evidence does this mean that the ignitor is Broken?

In my tune/install of MS what could have caused this ignitor to burn common reasons for ignitors to brake?

Will the new ignitor be likely to fix my tachometer and make it work again?

First post so sorry if its a nooby questions

Thanks will

 

What are your dwell settings?

 

what MS is this? a DIY MS1? who built it?

and MS1?

what basemap are you using?

is it setup correct for your ignition output mods?

 

My Dwell is Crank = 8.0
Running = 5.0
min discharge period 0.5

its a mega-squirt 1 v3.0 built by me using the information kindly posted in this forum and it is a parallel install

I could not find a base map(many of the links i found were broken so i used the settings i found posted around the forums from people that had the same setup as me (1990 AIT sensor stock injectors)

i did the ignition mod posted in the "how to make your own mega squirt" and i selected ignition output inverted "YES" Which i believe is right

 

How *exactly* did you set up your spark outputs?

 

yeah, knowing how the physical spark output mods are setup makes a difference in whether to select inverted or not. if not corect, it can/will burn up an ignitor.

 

hope this is what your after when you say spark out puts

 

physical. like the actual components on the mainboard.

 

oh it is done exactly the same as in your thread with how to make and install your own mega squirt

 

if you did the mods like that, then the spart output should NOT be inverted. Change YES to NO and you will no longer burn up ignitors.

 

ok the master has spoken thank you i must have miss read i always thought it was a "yes"

i am in the car right now and the ignitor is no longer hot and the car is idling well. however the tach still does not work in your educated opion do you think my new ignitor will allow the tach to work again?

 

correct, that part has burnt out. a new ignitor will fix it.


a 1K resistor from IG- to B+ in the diagnostics box might also as well.

 

It's a weirdly named setting, in that no means yes. (Kind of like what I tried explaining to the judge...)


When you set that switch to "No", the actual output pins of the CPU itself are in fact inverted, in that they go high to turn the spark output off. This is because the "typical" output circuit is, itself, inverting. (Which is why ignitors also fry when you re-flash the code; the CPU is off line, so it can't turn the outputs off.)

The JoeSpark mod corrects this situation by un-inverting the output drivers, so that they follow the actual state of the CPU. This eliminates the pop on startup that people with leaky injectors get, as well as making the re-flash procedure safe by causing the outputs to naturally want to be off. If you build this circuit, THEN you will want to select "Yes" for inverted, which in reality means that "No, my outputs are NOT inverted," for reasons known only to the original designers in what must have been a hilarious whiskey-fueled coding session surrounded by a haze of crack vapor.



On topic: If your ignitor is still functioning sufficiently well to drive the coils, and you don't want to buy a new one, you could build a Tach Out circuit in the MS to drive the tachometer directly.

 

Im Glad you got this all figured out. Remember, measure twice, cut once. Even then, go over it another couple of times to make doubly sure.

 

thanks for the help every one i have ordered a new ignitor not to bad price either $30 on ebay.

 

you DID NOT DO the JoeSparkMod

 

Incorrect. The "joespark" mod would necessitate selecting "YES".

You did not perform the Joespark mod, so the correct setting for you is "NO".

 

installed the new ignitor and everything works well and tachometer is back online
Thanks alot for the help guys

 

Glad you got this all fixed.

 

Sorry for the old thread bump. New to Miatas and Megasquirt.

Picked up a ‘90 NA with a ‘99 1.8 swap running a Megasquirt Plug N Play 3, but retained all the OE 1.6 ignition components, and the car has fried 4 igniters in basically 2 months of driving.

Initially I thought it was my lack of thermal paste(didn’t know it was supposed to have any, new units did not include) combined with the mounting plate being Swiss cheesed by the previous owner(less thermal mass), but the last 2 I fried, the car basically didn’t even leave the garage. Still going to replace that plate with stock and maybe add a heat sink, as well as thermal paste.




Hoping that dialing my ignition settings in TunerStudio will curb this problem once and for all!

Since I’m really not sure how this ignition system is setup, would it be safe enough to just change the “Inverted” option to whichever one isn’t currently chosen? Or should I really try to dig into things to figure out whether I want inverted or not?

Appreciate the knowledge !