MS2 v3.57 FIDLE & PWM Converter

[DocWalt]

Hi Jean,

I've got a v3.57 board and I'm limited to FIDLE for the PWM idle control. How do you suggest setting up the PWM converter on a v3.57 board?

Thanks!

[jbelanger]

Ken,

There isn't a perfect solution with the 3.57 board but one solution would be to remove R19 and use the 3.57 driver instead of the TIP12 provided with the kit. That means that you would connect a wire from Idle-1 either on pin 34 of the 40-pin socket or on the pad for R19; that wire would go to the IN pad on the PWM converter board. You would also need a wire to go from the pad on the PWM converter board for pin 1 of the TIP122 (the square pad) to input2 on U8 on the 3.57 board either at pin 4 on U8 or on the other R19 pad.

You would also need to wire 5V and ground from the 3.57 board to the PWM converter board. You would ignore the OUT, 12V and A_GND connections on the PWM converter board since these would be handled by the standard Idle driver on the 3.57 board. You would also not use the TIP122 and the diode on the PWM converter board.

Hopefully that's not too confusing. And refer to page 5 (and 1) of the 3.57 schematics to see the components I mention above. If you think this is not a good way for you, let me know and we'll do it another way which will require using a spare output pin on the DB37 and not require touching the surface mount components.

Jean

[DocWalt]

Wonderful help! I had suspicions that was how I'd go about wiring it up, but I didn't even think about using the U8 and was going to use the TIP122 on a spare pin, but that saves me the hassle of repinning the DB37 connector.

I should be able to manage the solder work with R19 if I buy new tips for my iron, and if not I can take it to work and our resident "pro" will be able to handle it.

Thanks a bunch, Jean.

-Ken

[DocWalt]

Jean, I completed the installation this morning, and it works perfectly. No more noisy PWM idle valve, and I still have the same duty cycle resolution. Seems to idle a touch smoother since the valve isn't bouncing due to the low frequency, which was the whole point of this install.

I'm a happy camper, thanks!

[jbelanger]

Good to see it's working and doing what you wanted.

So how did you wire it in the end? Directly to the R19 pad or at the other ends?

Jean

[DocWalt]

When removing the R19 resistor I partially lifted one of the pads and even though I snuck some super glue underneath I didn't trust that to stay, so I wired the IN to Pin 34 of U1, and the TIP122 Pin 1 from your PWM board to the other pad like you suggested. I excluded the diode on the PWM board, and installed a jumper for the 8x multiplier to bring me to 248Hz.

I'm using a Bosch 2 wire PWM idle valve, commonly referred to as an ISV in the VW/Audi world which uses 147Hz on the OEM ECU, but with MS's control method seems to react a bit better at higher frequencies. The factory uses current ramping on the idle valve, which is pretty neat. There's a modification documented to add that (see here: http://www.clubgti.com/showthread.php?1 ... -Bosch-ISV), and I may add that in the future since I'm trying to get an OEM-like idle with big 288* cams.

Thanks again, great product!