What a cluster ****.
That sucks man. Hate that kind of thing.

 

It's just another fun f'ing hurdle. I will get it to work

 

Dave, I'll try to get my COPs wired up this weekend.
I am getting with Jerry @ DIY Autotune in the next week or two max to get some other stuff taken care of in my car. I'll ask him to take a look at the COPs situation at that time.

I'd bet that Jerry or Matt C can get it figured out...

B

EDIT
Hey, in the mean time you might want to try to isolate the MS RPM input from the TACH RPM input with diodes.

 

right now i have it like this

COP Tach 1/2 -----> Ignitor 4/5 soldered together in ignitor.

So do ?:
COP Tach 1/2 -----> Ignitor 4 --->diode--->ignitor 5

My electronics usage is so lost in my head... I can't even process what I'd be doing that for...

 

That means the pin going to the MS is grounded. (since the MS gets its RPM signal from the cas as cj said)

When the MS together with the cop is in, you should really untie those 2 pins. Have you tried MS with Cop just feeding the tach cluster? see if you get rpm on both.

What does the DMM say?

 

good call ampz, I totally missed CJ's post. I did not know the MS got tach signal from the CAS and not from the ignitor. if that is the case, it could explain why MS likes to cook miata ignitors.

dave, a diode is a "check valve" for an electrical circuit. It only allow electricity to flow in one direction. i would have used 2 diodes, one at each ignitor pin, with the cathode (the side with the stripe) facing away from the COPs.

Try ampz's suggestion though, I think he's on to something.

 

Its dark out... but I'll try anyways. This needs to be solved. Back into the world of mosquitos i go!

 

Ok... i took the Tach signal from 4/5 at ignitor and just put it to 4.

Got a wierd pop on power up... car starts up but still no RPM on cluster. I checked engine bay and cabin fuses, all good. No clue what the pop was...

Hopefully I didn't blow something somehow on the cops.

 

After going over this in my head and talking to Split about what he's tried and what is or isn't working, I've come up with this.

In the MS install the black/white wire doesn't make a connection to the MS. It's possible that the factory ECU provides a voltage on that pin. I haven't checked the tach output from the COPs to see if it actually goes high or low but, reguardless of which, the tach will need to see the opposite in order to 'see' the alternating pluses. He's going to try a 1k to power or to ground and see if this is the fix for COP with MS.

Everyone cross your fingers.

If anyone has the time to help, please remove the black/white wire on pin 2I (i think) of the stock 1.6 ECU and take a meter to that pin and see if, and what, the ECU is sending out of it? Braineack?

 

Looking at
https://www.miataturbo.net/~web1_bra.../ecupinout.jpg

I see that 2I is outputing below .5v with Ignition On.... and ~1v at Idle.... So it looks like it feeds a 1v signal... which without the stock ecu... or possibly wiring within the ignitor... the tach signal isn't working with to feed the Tach.

 

hmm... perhaps we could use a 317 regulator then
would need to know functioning voltage and current demands first. the 317 will give us 1.2V and a half dozen or so amps...

also, Dave can you confirm the ignitor to tach signal goes to ground?

 

I don't believe it goes to ground. I believe it feeds the signal into the Tach, the tach itself is getting power and ground seperatly.

 

ok, so you're saying it just adds continuity between the 2 pins and supplies the tach w/ 1V 'rpm triggers'

 

I think so, my electrical speak is years gone... I can barely remember how to work anything without a guide .

Basically 2i outputs that 1v at idle... it goes to the ignitor... tach signals goto the ignitor... line from ignitor to diagnostic port and Tach in cluster. Tach in cluster gets its own power and ground.

Now what the stock ignitor does to that 2i input... I haven't a clue....

 

You might need a 1k resistor between the cluster and ground.


ground----------1k-------cluster---------coil/ignitor

Then again, maybe not. When I had stock coils and megasquirt, tach didn't work without that added resistor. The theory being that the stock ECU was pulling that signal down to ground, which I wasn't doing with the MSEFI in. That's with a 94, though. 1.6 might be a bit different.

-Mike

 

Yah, on my 93 1.6... everything works fine with MS and stock ignition.

 

stick a AA battery in there to see if the 1.5V pulls a signal?
if so then a small circuit would be in order.

i don't have my car here to measure those pins with the stock ecu (sorry)

 

It may be that it just needs -something- there to read a difference from the coils tach lead. I suggested the 1k resistor. Not enough current to hurt anything and worth a shot.

 

I still haven't had a chance to get to this.

Ben... have you had a chance to work on this with Foundsoul?

 

Nope, I was waiting to hear from you. Guess I'll go ahead and start building some COPs harnesses.