Hello! I switch to Toyota COPs, miata 1.6, on a 1990 Miata wiring harness using MSPNP2 for a 90-93. When I installed them I lost tach, but I jumper'd the tachout j6 on the ecu and now I get a signal and at idle it's correct, but when I rev fast it jumps around like crazy (while the signal in the ECU logs is stable). Unfortunately this on a Exocet with the wiring harness paired down to nothing so I don't have my diag box, the instructions claim I should put a 1K resistor on diag -IG and +B terminal. I have a shift light only (no stock cluster or tach) and it was wired from the diag box's tach-out.
Can anyone tell me where I should be sticking in a resistor or if there's another way to solve this?
What's your current dwell setting?
As per instructions I changed my cranking dwell to 3.5 and running dwell to 2.5, but I wasn't super confident in the place I changed running dwell. Lemme get a picture of where the setting was in tuner studio. For whatever it's worth I've driven the car and it seems to run super well and start much more easily than before!
That sounds like a pull up resistor so that the signal is less vague, it would create a square wave signal like the tach would expect.
It sounds like the tach was previously driven off the coil, now with COP you need to configure the MS tach output to run the tach. On a Volvo I did I had to add a relay coil to the tach output to get some flyback that would trigger the factory dash tach. This was MS2 not sure if MicroSquirt module handles the tach in the same way. I believe your PNP is powered by an MicroSquirt Module.
But! "J6: Tach Out on Connector J3, Pin 4I (1995.5+ Miata Only)
Unused on this model." < yours is 90 model
More digging here may help http://www.megasquirtpnp.com/docs/mspnp_g2_mm9093.php?isModel=1
Glad it runs better! That change must have been from a single coil or a messed up wasted spark system.
In reply to bentwrench :
I read the exact same thing, but this is my second 1990 Miata that without the jumper "that does nothing" the stock tack didn't work. I had to do the exact same thing on my VVT swapped Miata. Super weird, right?
Please make sure you have tach output enabled under Basic / Load Settings -> Tacho Output.
In reply to MadScientistMatt :
This enrages the small computer box:
TACHO OUT:ON
OUTPUT PIN: IGN
Tach out needs to on the TACHOUT pin and not IGN. IGN is already being used as a spark output.
Yeah, I was just about to report I'd switched it to that and no longer get an error. Thanks for the help so far, I will test it in a few!
In reply to MadScientistMatt :
Thanks Matt, that fixed it! I forgot that step apparently, I seem to remember having to do that for the silver car when I VVT swapped it as well.
