No tach ms2pnp
 

I have a 1991 with a 1994 turbo motor. I can't get a tach signal. I tried the resistor trick in the dignostic port and still nothing. What am I doing wrong lol

No tach in tunerstudio or dash?

Which coils are you using. 94? Or 91? Do they have 3 wires or 4?

I'm useing all 91 electornics so 3 wire and on the dash.

What did you jump in the diag box.

you did the resistor wrong, or you fubared your ignitor.

I did the IG- to B+ with a 1/4w 1K resistor. And I've got a brand new igniter.

I read though that. Was slightly confused though. I'm not running cops.

What should my tachoutput be in mega squirt?

Off.

Wait, if you are still running 1.6 coils and everything the tach should never have broken.

Dead fuse is my guess.

Oh ok I'll start checking fuses.

Do you have 12v at B+?

i wrote a huge reply and lost it explaining why the resistor works and why the tach goes dead when you pull out stock ecu, even though the 90-94.5's tach is driven through coils.

i dont feel like writing it again right now. :(

Now I want to know...even on 90-93 with the ignitor?

Dang that sucks Brain. Can u sum it up. It's just weird driving the car with no tach lol it's not a fuse.

Why does the tach go dead with the megasquirt?

because the stock ecu provided the pullup to power the tach signal.

the coils go to ground with each spark event.

the signal must have voltage to start with.

when coils ground, the tach sees constant voltage, then none -- the rate it sees those events is how it knows the engine speed.


1K from B+ (12v) to the tach signal (IG-) puts power back on the wire. otherwise there's no activity on the wire, cause youre going from no voltage to ground -- no signal.

Very nice. Thank you brain. I now understand it better. My megasquirt is set to tachoutput should it be off with the resister in place?

I don't think the mspnp's even have tach output hooked up. Or at least the jumper shouldnt be set. Adding the resistor is emulating the stock ecu. If adding the resistor isn't working you have bigger problems.

I have power to b+ no power at IG. Still can't get nothing to come on dash.

it doesnt matter if it's on or off, it's not connected to your car's wiring whatsoever.

IG- should be grounded.

spacing out

if IG- is grounded the tach will never work.

I'm gonna pull the cluster tomorrow and make sure I'm getting voltage to the gauge. It decided to rain 40ft down here in East Tennessee band my tops leaking. :/

The IG- pin in the diagnostic connector goes directly to the dash. Do all your tests on that.


When the car is running, and multimeter in diode test mode, you can put teh black lead to GND and red lead to IG- and it should rapidly beep at you.

If its a solid tone, then the ignitor has most likely been damaged.

So I'm having this problem with a 96 (3 wire coils), using a 94-95 mspnp2, re pinned to follow 94-95 wiring. Don't ask.

But we have no tach. Would the resistor trick work for this situAtion? Or is a 1.6 thing only?

no, it wont work for 3 wire coils.

you should have repinned your '96 from 4L to 2I and then use the MS tachout.


Tach is the Black/White wire. Even 90-94 wires has the b/w wire and use can use tachout on it, but you have to modify the engine bay harness to connect to the dash, where it would have done that in the ignitor to the yellow/blue wire.

Thanks brain I'm gonna try everything tomorrow after work. I'll report what I find!

Ok brain. I checked my coil it's a 3 white coil since I'm still useing the 1.6 electronics. Is it still the same?

Yes. The resistor trick still works.

The ignitor is techincally what's providing the tach signal -- it's sending a pulse to the tach everytime it tells coil 1 or 2 to fire.

I thought it was when it fired 3 or 4?

Ok I'm getting a solid tone out of the Ig. I swapped igniters and still the same. I'm so confused.

There's only 2 coils.

Each time coil 1 or coil 2 fires, that's a signal. It fires each coil twice a cycle.

even when the car is running?

Yep it's a solid tone. Either way I try it while running. Now i just remembered when I installed the coil packs I reversed the ignition wire signals so I could use the regular spark plug wire order. Could this be a issue?

If you fucked up switching the wires, yes.

Well shit lol I feel stupid. I'll swap them back and try everything again.

Well hate to revive this again. But I still can get a tach. Is there anyway I can run the tach straight out of the MS into the dash?

Yes. Run a line from the tachout either on the stock harness or the extra plug to the dash. Do this with a ~4' piece of scrap wire and a couple paper clips temporarily. If you have no tach, it's either your cluster (test with stock ecu) or your MS (send out for repair)

Ok I know there's a screw on the back of the cluster that the tach signal runs to. Can I run it to that? And will I have to change tachout in the ms settings?

see post #24.

you would have to first sever the conection to IG- from whatever is grounding it out. (probably the ignitor)

because even if you connect the tachout from the MS directly to the dash, and signal will be grounded and dump to ground.

at least that's what I think will happen.

i got it figured out! When I did the 1.8 swap I swapped the signal wires on the coil so my spark plugs would fit. I swapped them back and boom I gotta tach. Thank you for your help Braineck!