Tach wire - purpose?

[JiP]

What in gods name is the tach wires full function. I clipped it off today to see what happens. Obviously my afc and dash tach had no readings but engine runs perfectly fine, had my datalogger hooked up monitoring things and its all normal engine uses crank to get rpm signal so ...

Tach signal wire is only for the gauge cluster??

I didnt drive it with the tach wire cut so does anyone know if the a/t uses this signal also? I should try driving with it clipped and find out ...

[pinoyesv6]

ur car should have two sets of gauges. one for u. and one for the ecu. u most likely cut the one for you.

[JiP]

<div class='quotetop'>QUOTE(PinoyESV6)</div><div class='quotemain'>ur car should have two sets of gauges. one for u. and one for the ecu. u most likely cut the one for you.</div>

The wire I cut is the white wire on the coil of the distributer. That wire also goes into the ecu pin 31. The ecu doesnt use it for shit apparently. It didnt even throw a code. I thought it used the tach signal for the RPM, forgot that the cam or crankshaft is the most acurate way to grab that info. Silly me.

The reason I ask is because we are working on a standalone to let you go to coil packs, but the tach output on the power transistor is real weak think that parts busted. I can easily mimic what the tac output should be however the 7g tach signal average voltage is around 13v. Can't do that can only work with digital 5v max signals. Also want to work Knock controller into this setup ... thats after we get things fulyl working sparkwise https://www.thegalantcenter.org/style_emoticons/default/wink.gif

WHERE ARE THE MITSU TECHS!
Rob

[Kain]

That's a "signal cleaner" All it does is send a "tach friendly" signal to the ECU and than to the tach. It's there to make your tachometer work properly. If it gets damaged, or distroyed or removed, your tach will not work properly (Like in my Colt) The ECU for purposes of engine timing etc uses the CAS.

[JiP]

<div class='quotetop'>QUOTE(Kain)</div><div class='quotemain'>That's a "signal cleaner" All it does is send a "tach friendly" signal to the ECU and than to the tach. It's there to make your tachometer work properly. If it gets damaged, or distroyed or removed, your tach will not work properly (Like in my Colt) The ECU for purposes of engine timing etc uses the CAS.</div>

Yes thats what I wanted to make sure of. Not for nothing though, I had my afc for a long time hooked up to the CAS becuase before I got the ecu pinouts I couldnt find the damn tach wire on the ecu because its not listed in chiltons but CAS was so I hooked it there...worked exactly the same as the tach as far as afc was concerned But the cas signal is not a 13v average so maybe I can still fake it.

Then again I probably could just hook the dash tach up to the CAS line and comepletly ignore the Tach signal wire.

[JiP]

Odly enough that tach signal is the hardest part of this conversion, other then that we are done and ready to test its function in live engine.

If anyone wants to see the pics of spark plugs firing under my computers control on the floor of my bedroom, they are here:

http://www26.brinkster.com/faction8/Sparks.htm ('http://www26.brinkster.com/faction8/Sparks.htm')

I had them firing so fast that they were making a high pitched squeel https://www.thegalantcenter.org/style_emoticons/default/wink.gif Just to make sure the chip I plan to use can handle high revs.