3.57 TFI --> direct coil control, 3-wire PWM idle

Post here for the brain!

3.57 TFI --> direct coil control, 3-wire PWM idle

Postby Richago » Mon Jun 28, 2010 7:37 pm

I've got a 16v that's been running CIS-M. Still need a few parts, but I got all the electronics! I picked up MSII v3.57, uncut harness, sensors, etc., from a guy that had it set-up to run in his Ford. This ford used TFI (Hall-sensing ignition module). I'm trying to get it set up to control spark and my 3-wire PWM valve directly. Here are the changes I think I need to make on the hardware side; I haven't even started looking at which firmware to run! Most of the information I'm finding is for V3 or V2.2 - if anyone could help me make sure this is right or point me towards a v3.57 resource that'd be great!

Remove D1 (jumper around), Remove C12? (jumper around) in the hall-sensor circuit

Tach input Select JP1 replace diode (from TFI) with jumper 2to3
Tsel J1 jumper 1to2

remove pull-up resistor from S12 to Q16 (is this IGBT out?) for direct-coil control

JS10 to IGN jumper- already installed

S12c to JSC jumper - Powers stepper, tacho out, etc., so it can stay

jumpers JS0 to IAC1A, JS1 to IAC1B, JS2 to IAC2A, JS3 to IAC2B for stepper motor control - can I just leave these?

Install TIP122 for PWM, base to right side (after) R19, (intercepting the signal to power driver IC VNS3NV04D), collector to SPR1, and emitter to ground

My 3-wire Bosch valve gets the new output from MS (SPR1/3) with a 1N4001 diode (mounted across the valve terminals for flyback protection), 12v, and a lead to ground with a 35-40 Ohm 50w resistor to pull on the other winding.

disconnect the stock ignition amplifier located on my coil

IGBTOUT to IGN - hard-wired on v3.57

Thanks a million for any input! I've been spending so much time in front of my computer it's not even funny...
Random avatar
Posts: 1
Joined: Mon Jun 28, 2010 7:19 pm

Re: 3.57 TFI --> direct coil control, 3-wire PWM idle

Postby prof315 » Tue Jun 29, 2010 5:03 am

http://www.megamanual.com/index.html Go to the V3.57 assembly guide. Leave the stepper IAC stuff in place, you can use IAC 1 and IAC2 as spare outputs. As for firmware selection I like MS2/Extra, either v2.10d or the current V3.0x alpha code. Also you don't need the TIP 122 on a v3.57 mainboard. There is already a pwm circuit built on it. And last but certainly not least dump the 3 wire ISV and get a 2 wire digi or OBD1 VR6 or OBD1 ABA ISV. Nobody (including the firmware developers) has had very good luck with a 3 wire pwm idle valve and MS1 or MS2. MS3 has specific 3 wire pwm IAC circuitry on the MS3X expander but it is still in beta testing or you can get a Glen's garage Expansion board which also has a 3 wire specific circuit on it.
User avatar
Posts: 59
Joined: Tue Dec 08, 2009 7:33 am
Location: Melbourne, FL

Return to Megasquirt computer

Hosted by Freeforum.ca, get your free forum now! TOS | Support Forums | Report a violation
MultiForums powered by echoPHP phpBB MultiForums