Hey guys, I'm running a mspnp2 94-95 with a 99-00 head/intake/TB/IAC.

I'm having an issue where a single IAC step results in large swings of rpm, while other steps have no effect at all. I'm using a multiplier of 15 to control the IAC. Closed loop idle.

For instance my idle target is 950 when warm. Step 55 might give me 920 rpm, so closed loop tries one step up, 56. This might result in ~1030 rpm, so it drops back down to 55. Repeat forever.

I've also noticed that in test mode, not all steps will change the idle. It's only maybe every 5-7.

This leads me to believe I'm using the wrong frequency to control the IAC.

99-00 should be 500 MHz, yeah? Which would be x16? But tunerstudio only allows up to x15.

What am I missing?

 

Try the 3.4.2 firmware; it has some improvements to idle control resolution and lets you specify the frequency directly.

 

This is the old board. V1.2, is that fine? I'll double check when I get a minute later today.

 

Hey Matt,

I successfully updated the firmware, and after some fiddling with outputs being moved around, got the car to run. However Tunerstudio is reporting it's not in sync.

Can you take a look?

 

RTFM!

"Not Synced" was changed to "Not RPM Synced" in the newest firmware. So my little red indicator telling me I wasn't in sync was completely wrong. I just had to delete it and make a new "Not RPM Synced" indicator. All is well!

Idle works much better too