MS won't shut down

[Davek]

I assembled my MS3X 3 or 4 years ago and installed with my homemade wire harnesses. I had IAC valve issues that I assumed was my homemade wire harness possible shorting or who knows what.
I use a 2 wire PWM Ford style idle valve.
Back then I installed the TIP122 as described in the manual page 44-45. And used MS harness wire #30 to control the IAC valve.

recently I purchased new MS & MS3X wire harnesses from DIYAUTOTUNE. During installation I added the wire from S12 to C end of D1 on the MS3X card per page 231/2 of the manual. And use MS3X harness wire #9 to control my idle valve.

MY PROBLEM:
If I remove my MS fuse MS is still powered up. I narrowed this down to my idle valve. With idle valve disconnected MS shuts down as it should. I have fused 12v power off same fuse panel as MS.

Couple questions: Possible I have a bridged solder somewhere. I've been all over the board and don't see a problem---are there some areas I should be looking on the board. Second is TIP122 installation conflicting with the new wire I installed. I am not using TIP122 now.

MS seems to be working and idle valve responding. I have not driven the car and only run engine up to temp once since new harness.

This issue may have been present with my old harness. I don't recall ever pulling the MS fuse as I did this recently.

Would it help to know how my previous IAC valve was acting?

[jsmcortina]

If I remove my MS fuse MS is still powered up. I narrowed this down to my idle valve. With idle valve disconnected MS shuts down as it should. I have fused 12v power off same fuse panel as MS.

A. Don't remove the fuse.
B. Take the 12V feed for the idle valve from the fuel pump relay circuit. Then when the ECU is off, do is the relay and there's no backfeeding.

James

[Davek]

Awesome & fast response James
I will try tomorrow after work.
I was thinking the worst.