low idle on cold start

[rwb137]

I have recently purchase a 92 gsx. I am having problems with the cold start idle. When I would start it up it would idle around 2000 rpms and start to surge a bit when moved. I checked all the normal stuff and then after thinking. I purchased a new fiav from norco mitsubishi thinking this was the problem. When I first installed the fiav everything was working great. Idled at 1500 rpms and gradually dropped during warm-up. But in true dsm style a week later it decides to idle at 750 when cold. The pocketlogger show no signs of problems other than when I check the fuel pressure solenoid it doesn't work. I traced this down to the ecu pin 57. I installed another ecu and it the fuel pressure solenoid worked. I had new capacitors replace hoping this was the problem because the front one was bad. Got it back and it still doesn't work. I check my isc and the ohms readings are high at around 37-40 ohms.
My 90 fwd turbo dsm isc check around 27 ohms in the same temperature garage.

So my question are

Could the isc cause low idle at cold startup?
If the ecu isn't working at pin 57(fuel pressure solenoid) could there be other problems that a pocket logger or check engine light wouldn't indicate.

The 92 gsx 5sp is 100% stock other than a k and n filter.

 

[1SloColt]

Does it idle low upon initial start up then gradually rise as the motor warms up?

 

[rwb137]

No I idle 750 the whole time. even when initially started. I thought the new fiav was defective because nothing else makes sense so i took the fiav off again and took it apart. The element that gets heat by the antifreeze is working because I heated it up with a propane torch and the valve moved.

Usually when you start a dsm the engine always revs to like 2000 rpms to increase oil pressure quickly and it isn't doing this signature start. Just bogs down in the low rpm where my throttle assistants is somewhat needed. Sending the computer to steve and purchase a different isc. then hopefully everything starts to work. Once semi warmed up it idles perfect with no codes or pocketlogger values being obviously wacked.
This is why I love, always a mystery.