Desire to smash IAC... High

[Threshld1]

Ok looking for some input here. I recently acquired another Tleg for dirt cheap.

91 Auto - Bone Stock

My problem is durring cold starts (either in the 0* MN temps outside or 50* in the shop) it will throw an IAC, Canister Purge, and BCS code. It idles very rough and any aggressive throttle will cause it to stall instantly. If i let it run for 2-10 min it will all of the sudden clear the code and rev up to 2k for about 5 seconds before it levels out and runs fine. After this i can drive it, boost it, no codes are present.

When i first got the car it had 11 stored codes with the same symptoms. The codes would not clear no matter what i did so i replaced the ECU. Ran great for a day with no codes present in test mode (both connectors connected) then the 3 codes showed up.

Parts ive replaced from my trouble free 93:
-IAC - Ohms properly and shows voltage on the two trigger wires. Cleaned pre/post install
-MAF
-Canister Purge - Ohms properly
-Coolant temp sender
-93 Auto + 93 MT ECU's
-Knock
-Coil Pack
-Igniter
-Plugs/Wires


Grounding from Harness to motor and chassis are <.3 ohms

Ideas?

[Threshld1]

Well if it helps anyone i figured out the problem. Turns out the pressure exchange solenoid had a resistance of ~2Mohms. Replacing it with a 40ohm solenoid has solved the problem. I suppose its too much to ask the ECU to throw the code for the bad solenoid and not 3 other unrelated parts... Grrr

[adema2626]

Hmmm you might have just solved my problem... Because i was throwing those same 2 codes and getting similar issues but mine would boost and do everything else. Just idle like hill till the IAC code went away which it didn't when i started driving.

[04.STI]

whats this part looks like, wheres it located, i changed numerous sensors on my legacy and it still shows the same ones. after a reset.

[04.STI]

is that it?

[Legacy777]

That's part of code 45.

That's the pressure exchange solenoid. Code 45 also includes the pressure sensor which is just to the left and below of the pressure exchange solenoid in that picture. Also the hose from the exchange solenoid goes to the pressure sensor.