This is on my '90 5.0 HO into a TR4 project:
Can anyone tell me, if I disconnect the TAD, TAB and the EGR relay, will that just send error codes or will it drive the EEC to 'Open Loop' mode?
Can someone tell me what exactly will drive the EEC to 'open loop'?
Also, I don't have the speed sensor that should be on a '90 Mustang T-5, I've been told that on some cars it won't matter, and some cars will stall when they're stopped as the EEC doesn't know the car is stopped. Anyone have any more on this?

Still Crazy After All These Years

 

Look into getting a Tweecer - www.tweecer.com
It'll allow you to force open loop mode iirc.

 

i dont remember all the things that turn open loop on, but i know coolant temp is one.

 

oh, wait. you're trying to avoid open loop mode. hm
swap to carb and be done with it.