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Well technically I am only running it with one right now as I haven't run Spark C and D out to the coils yet (Running wasted spark). Assuming a dwell of ~2.0 at 7000rpm (x2 for wasted) wouldn't a 4 ms dwell only be around 25% duty?
Are you still running in wasted spark? If so, how's it holding up? I'm in the same boat of not wanting to run additional wiring out from an MS3x.
Are you still running in wasted spark? If so, how's it holding up? I'm in the same boat of not wanting to run additional wiring out from an MS3x.
I'm running mine in Wasted Spark and have been doing so without issue for a while. At this point I've put a few hundred street miles, and over 6 hours of track time on my setup and it has ran great that entire time for me. Would definitely buy again.
Alright all you cool cats and kittens. I was able to get my MS3X running correctly using TC4427 on the proto area of the MS base board. I made one modification to the recommended layout. Instead of using the LED spark outputs I took the series resistors off of the current MS3X ignition outputs of U13. This way I could retain knock sensing functionality. It goes something like this.
MS3X V3.0 TC4427 Implementation for low impedance VAG Coils
U13 Pin 11(MS3 Expansion Board) → first TC4427 Pin 2 (In proto area of MS Base board)
U13 Pin 12 (MS3 Expansion Board) → first TC4427 Pin 4 (In proto area of MS Base board)
U13 Pin 13 (MS3 Expansion Board) → second TC4427 Pin 2 (In proto area of MS Base board)
U13 Pin 14 (MS3 Expansion Board) → second TC4427 Pin 4 (In proto area of MS Base board) (I used R62, R63, R59, R60 pads that were on the U13 side to jumper to proto area) First TC4427 Pin 7 -> 15 Ohm resistor -> Expansion board DB37 Pin 14 First TC4427 Pin 5 -> 15 Ohm resistor -> Expansion board DB37 Pin 33 Second TC4427 Pin 7 -> 15 Ohm resistor -> Expansion board DB37 Pin 15 Second TC4427 Pin 5 -> 15 Ohm resistor -> Expansion board DB37 Pin 34
This way we are still driving spark with the native MS3X spark driver, but adding high current capabilities by putting TC4427 in series with the original buffer. We can retain knock functionality on daughter card (instead of using LED spark output to drive TC4427, as stated in the MS3 base instructions)
when running this circuit where do you tap back into the board to run the tc4427 outputs to the spark A,B,C,D ? does anyone have a picture to help me out?
Just got my kit with bracket installed today. So far it's running great except I have no tach signal. I also had to trim the bracket down at the front of the valve cover since it didn't want to sit flush and the holes wouldn't line up. I am running a Ford Escort 1.8 cover but I'm sure if it was a regular Miata cover it would be fine.
As for the tach it's a 90 with a 1.8 swap running MS3Pro PNP. If anyone can advise on how to fix that it would be a big help.
That's the plan however I'm getting conflicting results with my searches. I'm not sure which wire to use at the cluster and the MS3. Do I need to add an additional wire to the auxiliary connector on the rear of the MS3 and run a wire to the cluster? Or is it possible to cut and loop the tach wire at the ignitor and change a channel setting in the MS3 to use a different output for tach?
Last thing would be what settings should I use for the tach? Fixed or variable?
While there is no 1 way this is done, I believe many PNP solutions are setup to use 2I (BLK-WHT) shorted to YEL-BLU with a 1K pull-up in the diag connector. Brain had a writeup of sorts a long time ago. TACH output is a dedicated pin on most MS variants.
I seem to remember maybe aidandj had a good one too, but I didn't dig too deep.
Edit: just looked at DIY's 90-93 MS3PNP Pro pinout, looks like they mapped tach out to 1F, which can be shorted to YEL-BLU in the diag connector. It is also available on options connector 2D. ECU 4I is N/C (BLK-WHT), so a jumper in wire in the ECU case could also be used.
Lots of ways to do this.
Last edited by Ted75zcar; Aug 6, 2022 at 03:03 PM.
It turns out I had a resistor in the diag box from running the Toyota coils. However I put a jumper between the ignitor pins 4/5 but no luck. Before running the jumper wire the tach wouldn't bounce when key on but now it does. It just doesn't display RPM. Should I eliminate the resistor and use a jumper wire there or try something like an MSD tach adapter? Not sure why this is so confusing to me.
Did you try running a resistor from B+ to FEN and then a jumper from FEN to IG-?
Tach is configured for tach_out?
You have a DIY MS3PNP PRO?
Connecting those pins (4-5) in the ignitor plug would need to be done in addition to wiring pin 4I in the ECU to one of the tach_out signals (soldering a wire in the ecu case).
This is the ECU I am running. I will try to jumper the wires in the diagnostic box as you suggested. I only had IGN - jumped to the B+ which ran the tach on the Toyota coils. I will run a second jumper and report back
I figured out what my issue was. I didn't have a jumper in 4I inside the MS. I installed a jumper then jumped pins 4/5 at the ignitor together and bam the tach works. I also have a 1k ohm resistor in the diag box.
I'm going to make a separate how to thread in case this issue comes up again with someone having a similar setup.
I figured out what my issue was. I didn't have a jumper in 4I inside the MS. I installed a jumper then jumped pins 4/5 at the ignitor together and bam the tach works. I also have a 1k ohm resistor in the diag box.
I'm going to make a separate how to thread in case this issue comes up again with someone having a similar setup.
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