MSefi.com read only forum (Jan.15,2018)

Hello!

I am using MS 2 with an EDIS 4 setup; I was using pin 2(IDM) on the EDIS module to drive my Autometer Shift-Lite tach - but at 7500 rpm the needle starts to flicker heavily. So I tried pin 11 (should be the CTO) of the module to see if there is a difference - but there wasn't one at all!
On the datalogg I can see the engine is reving to (the set) rev limit at 8000 perfectly - no spikes or errating readings.

(Maybe the IDM and CTO port of the module are connected internal?!; maybe there is a built in "engine failure signal" from the module to the OEM ECU - because I guess in OEM applications they never reved to 7500+rpm....)

So my question: Can I add my tach signal input cable to the PIP signal cable which is a perfect square wave signal up to 8000RPM?

Thanks!
Harry

Driving the tacho from EDIS PIP is OK, as long as you check the load.
Scope the PIP wire and note the amplitude, should be > 10 Volts.
Then add the tach wire and recheck amplitude, should still be > 10 V,
but the tacho may well load it down.
If so, fix a simple emitter follower and drive that from the PIP, the input
impedance on a typical 2N2222 emitter follower is > 25 kOhms and
that will settle the issue.

Heribert

Hi Heribert,

thanks for the reply; the problem is I don't have a scope and I am not an "elecronic guru".

Do you have a schematic for me how to connect the transistor?
Would it maybe also work to add just a resistor(poti) on the input side of the tach to put the load down, but still let enough signal through to drive the tach?

Harry