No RPM Signal Under 2000 RPM

[jwill214jacob]

Hey All,

I'm a first time user of megasquirt and trying to run it using Ford EDIS. My setup consists of Megasquirt 2 V3.0 board. I also have a JimStim v1.5 to test my changes.

When I bought the board, it was pre-assembled and running a dual VR from jbperf. I removed the wiring from the underside of the board to set it up for Ford EDIS since I will not have a cam position sensor. I confirmed that the assembly of the board was done correctly and confirmed that step 50a was correct. I then followed the below for EDIS

V3.0 main board:
DB37 pin #36 to the SAW pin (#3) on the ignition module
DB37 pin #24 to the PIP pin (#1) on the ignition module
On the V3.0 main board:
use the 'Hall sensor circuit' (step #50.a in the assembly guide) - jumper D1 and D2,
jumper OPTOIN to TACHSELECT on the bottom side of the PCB, near the DB37 connector, opposite the heat sink,
jumper TSEL to OPTOOUT on the bottom side of the PCB, near the center.
jumper JS10 to IGN (this uses the processor port for the SAW signal directly),
jumper XG1 to XG2 on the bottom side of the PCB, near the 40 pin socket,

I also setup the following through TunerStudio

Trigger offset = 0° (this will vary slightly, depending on the wheel/pickup configuration),
Ignition Input Capture to 'Rising Edge', ('Falling Edge' for MicroSquirt® only if using the VR input circuit - not recommended),
Cranking Trigger to 'Calculated',
Coil Charging Scheme to 'EDIS',
Spark Output to 'Going High (Inverted)', ('Going High (Inverted)' for MicroSquirt).
Trigger Wheel Teeth to '0' (zero)

When I plug in the JimStim and turn the RPM coarse knob, the RPMS go off the charts, 30K. If I turn it all the way down, and use the fine adjustment knob I can get readings only above 2000 rpm.

I know the JimStim is OK because when I first bought the board I tested it in the original configuration and all was good.

Any one have any thoughts of what I can look for? I'm still working on getting a datalog. Like I said I'm new to this.

Thanks,
Jacob

[DaveEFI]

If you follow the latest manual, linked to from the top of this page, the current way is to use the VR input for EDIS PIP.

[jwill214jacob]

After posting the original question I reviewed the latest manual and rewired to use the VR input (pg 67 and 68) but the condition did not change. I played around with it a little more and found that the coarse RPM adjuster will read realistic RPM (4000) at certain positions on the dial. (Ex: If the knob is at the off position as soon as I turn it to the on it jumps to 30k but if I continue to turn the knob, there are a few spots that read close to 4000. As soon as I turn slightly clockwise or counterclockwise away from those "sweet spots" the RPM returns to 30K.

The dual VR chip is still plugged in but there are no longer any wires running to the "Proto" Area on the board so I don't think that would affect it. Correct me if I'm wrong.

Thanks,
Jacob

[retired]

Have you reset the DIP switches on the JimStim to EDIS mode (all switches off) and not 36:1 (switch 3 on) as you will presumably have had it before when you said it was working with the dual VR board ?

A couple of other possibilities,
If the main MS board was assembled specifically to use Jean's dual VR board the normal tach circuits may not be complete or not fully jumpered (I have built a V3.0 board in the past specifically to use Jean's dual VR board and left all the usual tach circuits off completely).
Or,
The previous builder may have added Jean's dual VR because the standard tach circuits were wrong or not working for some random reason.

But I'd check the DIP switches on the JimStim first.

[jwill214jacob]

I followed the assembly guide for EDIS listed below.

VRIN and TACHSELECT are linked
VrOUT and TSEL are linked
Connect (1A)JS0 (under the processor socket) to IAC1A (near the DB37 connector) - this brings out IAC1A on DB37 pin #25
Connect (1B)JS1 (under the processor socket) to IAC1B (near the DB37 connector) - this brings out IAC1B on DB37 pin #27
Connect (2A)JS2 (under the processor socket) to IAC2A (near the DB37 connector) - this brings out IAC2A on DB37 pin #29
Connect (2B)JS3 (under the processor socket) to IAC2B (near the DB37 connector) - this brings out IAC2B on DB37 pin #31
JS10 to IGN are linked
XG1 and XG2 are linked
D1 and D2 are jumped

These are the only things needed to complete the tach circuit, right?

What are the differences between building a V3.0 for a dual VR and a normal setup on the top side of the board?

Jacob

[retired]

What are the differences between building a V3.0 for a dual VR and a normal setup on the top side of the board?

Well basically you, or rather whoever built it, can leave most of the tach components out completely from the main board if Jean's dual VR is wired in to replace it all.

I'm not suggesting that is what has happened, it's just a possibility that some parts or some jumpers are missing if the build was intended to use Jean's dual VR only.

Much more likely from the RPMs you are seeing in TunerStudio with an EDIS msq is the JimStim is still set as a 36:1 signal and not as an EDIS signal.

Some of the other jumpers on the JimStim may not be ideal compared to how you presumably had it set before to work the dual VR board but that's another issue.

BUT, have you actually reset the DIP switches for an EDIS input ???

[jwill214jacob]

Man, I feel dumb. That was the issue. Thanks so much for helping out a newbie.

Jacob

[retired]

Thanks so much for helping out a newbie.

No worries, we all were once....

Bear in mind that this only tests your configuration and settings on the MS2 itself, it doesn't test your actual EDIS module is working as expected because you have just told the JimStim to send out what the EDIS module is expected to send out, and send it straight to the MS2 like the EDIS module would.

That's not a problem so long as you have a known good working EDIS but just bear in mind you haven't actually tested it by using the JimStim this way, you have only tested the MS2.

Good luck with your project anyway.