Connecting 92 tach to DIYPNP
 

I have a 92Miata running a DIYPNP and VVT controller to run a2001 engine. I connected the 01 coils through the 15 pin connector. now my tach doesn't work and I understand why but can I use the tach out in DIYPNP through the 15 pin connector to the yellow/blue tach wire and bring my tach back to life?

yes

eh,..no.

I wired the tach from the DIYPNP TACH to a pin on the 15 pin connector then out to the 92 Miata tach wire (yellow.bluestripe) Turned it on and still no tach.

I'm using the 2001 coils on this car.

Here's the settings I used on the tach output.

What am I missing?

thanks

You need to grab a 1k 1/4watt resistor, open your diagnostics box and jump IG- with B+ with the resistor. Or you could do the same within the MS box by jumping that Tach input wire with a 1K resistor to 12v inside the unit itself.

It needs a pull up on the signal and there is none currently.

The pull up is already in the DIYPNP.
I'd suspect something more along the lines of a wiring problem.

then are we certain "the pin" you picked on the db15 is the same that is going back to the TACH hole on the mainboard?

That was my thought as well. I would suggest checking for continuity back to "TACH" on the DIYPNP main board.

I'll check for continuity. Thanks

I checked continuity and found a wiring issue in my fat fingered soldering on the 15 pin connector. I fixed it by moving both wires to the next pin on the DB15 and had continuity, turned on the Tach output, fired the car and still no tach.

Can the pullup fail? Can the tach fail? Worked fine with the MSPnP

Or are there other settings that I'm overlooking?

I could never get the tach to work on my 93 with the diypnp. I went back to the 1k resistor in the diagnostics box. When I enabled tacho after wiring into the blue yellow wire; the tach signal worked fine at idle, but didn't move correctly with engine rpm. Maybe I wired something incorrectly in the diypnp

Where are you tapping into the yellow/blue wire?

I tapped the Yellow/Blue wire where it comes into the Diagnostic connector on the drivers side of the engine bay.

yeah that should work. is the ignitor still plugged in?

The ignitor is still plugged in.

unplug it and see what happens.

Oh? Yes, you 100% need to unplug it. It has a tach output on it.
I'm not sure if that has any negative implications as far as potential damage to the DIYPNP tach driver (which is on the module).

I clipped the wire under the dash on mine,a nd then connected the tach out wire to it.

Should I have also cut the tach feed wire coming out of the ignitor?

OR does that mean that when you install cops with a diypnp you do not need to run the tach signal wire to the COPs?

Well the Coils are what send the signal to the dash tach. so if you have both the coils AND diypnp sending out a signal, that could be an issue.

I had a gutted igniter in place to keep a factory appearance and my fuel pump would cycle in short bursts. I didn't try starting it at that point. When I swapped in the working igniter the fuel pump quit cycling. It would do the normal startup fuel pump routine...

But I removed the 92 coils and replaced them with the 01 coils that don't utilize the 92 ignitor. Does the ignitor itself generate a signal?

that response was for djp....the ignitor does yes, or at least hold it to ground preventing it from working.

Yay! I has tach!

I removed the ignitor and cranked the car up and hallelujah the tach does what the tach is to do!

Thanks Brain and Ben


Now to get it to idle faster at cold start...

:friday:

Tune those closed loop idle settings and increase the rpm targets in colder cot temps

I had TS hick up as I was loading a file into my PnP. The motor stalled so I went back to another tune and it started right up but now I have no tach.

All the other gages work fine and so does the virtual tach on TS dasboard but not the car's tach.
It is a 91 running the OEM ignition coils.

What did I fry ? :vash:

Thanks guys

the ignitor.

I think you are right but I used to have a tach when I had COPs

This made me think the tach got the signal from the Megasquirt unless it was working from the COPs somehow ....

dash tach gets signal from coils.

???????

the tach on your dash gets its signal from the coils directly.

Thanks !

How about the firmware ? Could I have mucked that up ?

I'm going to try it when I get home today.

Tried my COP set up yesterday - It has 2 bad coils. The tach does not work but it may be because of the two bad coils ( ? ).

Just for giggles I ordered an ignitor. I could have used the money to buy replacements for the blown coils but I still want to have the OEM ignition system as a back up.

I'll try to do more research on the weekend.