'99 NB Miata - Can't get a cam signal
 

Hi guys!

So I just built an MS3 with MS3X following the manual on MSExtra. All is working properly, except I can't get a signal on the cam sensor, using the composite logger.

The crank input seems to be working fine. I unscrewed all of R52, tuned R56 to ~2.3V measured on R45 and jumpered TSEL to VROUT and TACHSELECT to VRIN. There's also a 5V pullup from the protoarea to VRIN as indicated by WestfieldMX5's tips (here: http://westfieldmx5.devocht.com/mega...ms3/99-05-ms3/) which I followed afterwards: The manual leads to believe the Miata sensors are VR, while WestfieldMX5's tutorial shows they should actually be Hall / Open Collector.

The cam input is just using the MS3X Cam input, with JP7 jumpered. R11 on the MS3X was tuned to ~ 2.4V. Cam signal from the car/stim is connected on MS3X Pin 32.

On the car, I got absolutely no response on the Composite logger.
On the Jimstim, using 99-00 Miata mode, with no pullups on the signals and using Hall (square wave) circuit on crank, and directly wiring 2nd Trigger to the MS3X input, I get only the crank signal and that's it. Tried playing around with the ignition settings (rising edge, falling edge, etc) to no avail.

What have I done wrong?

Using the Jimstim:
https://www.dropbox.com/s/iwjan9d45j...ger01.PNG?dl=1

Used these as reference for the wiring loom. Car is a 1.6, however the wiring is exactly the same as the 1.8 except for the absence of VICS.
https://www.dropbox.com/s/i73v6abojh...-ms3x.jpg?dl=1

Cheers.

trubokitty.com for all your miata MS needs.

That's an awesome site, but after reading all of it, several questions arise...

According to that site, no pullup is needed on the cam or crank inputs. So I removed the pullup resistor from 5V to VRIN, and jumper JP7 on the expander as well.

Same behaviour though... No cam signal at all! Do I need to modify some setting on the stim?

I do mention the pull-up on VRIN.

as far as the one on the expander board, it comes installed so I dont mention it.


Sounds like dont have have teh cam signal inputting into your MS3x when using the jimstim. You must connect the 2nd trigger from the jimstim, directly to pin 32 of the expander DB37.


ugh: I always misspell necessary that way. Every time...

Hi Brain,

Sorry, I must've missed it. I put the pull-up resistor from yesterday in the trash bin, so I assume it's safe to go as per the manual and install a 470R instead of a 1K?
As for the expander one, I'll be putting it back.

The stim problem, I can't say for sure, since I'm pretty sure my stim is damaged at this point. Been a year since I last used it, and the power regulator is now heating up which means the processor is gone. I can't get any signal whatsoever right now, so stopped using it. I'll be doing some more testing in the car today.

Should these settings be okay for an in-car test?
https://www.dropbox.com/s/kg200s5jic...tings.PNG?dl=1

Thanks in advance.

yeah, if the regulator is hot, there's an issue and the CPU on the stim is toast.

Houston, we've got signal :)

Tach and cam signal is working on the car with these settings and I got it to barely idle, which is good!

The fuel pump is not being driven tough... Does it require any mods/pullups, or should it work straight off the F/P wire on the main connector?

Sorted. After looking at the stock ECU and the plug pinout, moved the F/P wire from 3N to 3P. Worked a charm!

Thanks for the tips! ;)