two wire iac valve

[racerron]

if my 3.0 ms1 board has the tip 122 for the ford iac valve and i buy the ms3 daughter board. what do i do with the old modification to my board if the ms3 does not require this modification? by the way im planing on converting my ms1 to a ms3 (ms3x) also using 8 low-z injectors. what do i need to buy and do to my ms1 board to make this work?

[dontz125]

By itself, the MS3 card DOES still require the mod to use a 2-wire PWM valve. If you add the 3X card, you can run the idle valve off the 3X pin, or just leave it where it is - why change wiring if you don't need to? If you do decide to use the 3X pin, you don't need to do anything to the main board, just leave the mod as-is.

The 3X board really isn't meant for lo-z injectors. You'll need to either run individual series resistors, or get 2 jbperf Peak & Hold boards.

[racerron]

all i would need is (8) 3r3 25 watt resistors? how would i make it a peak and hold?

[racerron]

i have a msd distributor with the vr sensor would i have to remove all but one of teeth one the dist. and then install a trigger wheel on the crankshaft?

[Matt Cramer]

all i would need is (8) 3r3 25 watt resistors? how would i make it a peak and hold?

They limit current to the "hold" level, which makes for a slower opening time than a true peak and hold circuit but does get the job done.

i have a msd distributor with the vr sensor would i have to remove all but one of teeth one the dist. and then install a trigger wheel on the crankshaft?

That's one way to get sequential EFI.