are you on stock coils? your running dwell is way too low.

should be 5ms running and a discharge period of closer to .7ms to 1ms. it probably cant charge enough to make spark when you get above 2000rpm. plus your fueling is completely whack.

 

I threw the timing light on it to verify timing was correct and in sync.

When you hit that limit the timing light dies out like the tachometer on the car's dash and is erratic.

 

Yes stock coils

at 5ms I can only go up to 1300rpm~ before spark breakup

if its .7 to 1ms discharge why does diy have .5ms

Anyways I'll try 1ms and see what happens

 

Can anyone tell me what the yellow wire and resisitor is for on this board?

Thanks

 

It's for a pullup on the CKP signal.

 

Signal looks like this on a oscope at lower rpms
_-_----_-_----_-_---- etc

once you get past say aroudn 2500
it goes like this

___----___----___----___----

 

Well an update

With the oscope, going over it more and testing newer non hires firmware 029y4

I noticed if I set to 5ms which leads me to hitting out at a max of 1300 rpms before it has the odd problem
Spark inversion set to yes

IF I set spark inverted to no

It registers on the oscope as it would if above 1300 rpms on yes
But once over 1300 rpms on no it registers like it would below 1300 rpms on yes

Any thoughts on this odd problem?

Changing running dwell seems to alter where this point is at, but it also alters how much gets to the ignitor, tried 1ms but car wouldn't work at that, 1.5ms was the lowest. Even that I hear is to low for the miata iginitor. Something sounds wrong.

Now I admit I'm not the sharpest at reading oscope outputs, first one to use but this seems to me what is happening.

 

Back with more info

More interesting information off the oscope, setting the crank trigger settings as a 4+1 instead of the stock miata 4+2 makes the output from the spark out work fine, as rpm increases the trigger events start happening closer together, yet it doesn't change how the output is showing at any certain point.

I used settings from this page http://msextra.com/forums/viewtopic.php?f=4&t=27543

so far it seems to only do it with this miata CAS setup and all firmware versions I've tried so far

029q 029y4 and newest hi res. I think its possibily a software problem, some overflow\stack overflow that cuasing the spill over.

ok so I put it back to stock miata settings cept now I changed it to dual dizzy = yes, and the output looks like it should.

 

It sounds as if you may have something wrong with the second trigger input and it's filtering out the shorter pulse on the second trigger. I wouldn't expect a code bug for the simple reason that it hasn't surfaced on other installations. Scoping the second trigger input may shed more light on the issue.

 

 

Did you scope the second trigger with the MS on the car? It sounds to me like the signal there is getting a bit wonky.

 

Matt not yet because the car was in process of getting the diff changed out. I will probably have it done within a couple days.
What should the 2nd trigger output look like, so I know what to compare what I see to it.

 

It should be a short-long-short-long pulse train, one short and one long pulse every rotation of the CAS. Check both the signal right at the CAS and at the input to the processor - it almost sounds like you're losing the shorter pulse.

 

Back when I had the MS1 and a '96 CAS on my 2002 engine:



Dimitris

 

well lets say I was losing the shorter pulse which I will check, wouldn't that be steady and not change based on running dwell. I'm still gonna check it though

 

thanks for the pic.

 

If you are losing the shorter pulse, you'd need to make sure the resistor (or the capacitor) is not too large.

 

riddle me this
One of my spark outputs at idle looks like its full 5v across the scope

I attached the oscope to the MS while running at idle
one of the spark outputs looks normal _-___-___-___etc
The bad one just looks like this ---------- full on 5 volt with small up angles at certain points of firing. Thoughts?

You can get a 4 cylinder to run on 2 cylinders, smell like gas and have good AFRs at idle

 

Anyone have an idea why I'm seeing full on 5v right off spark A pin on the cpu but spark B is ok?
Thanks
Justin

 

Soldering short somewhere?