Like the title says, I picked up a car with an ae101 swap, yesterday. The car runs great, although rich, as long as you keep your foot on the gas. It has no idle at all. Doesn't matter if its cold or warmed up it just dies if it gets below ~1500rpm. I know that's about the cutoff for the ecu to be in idle circuit. It doesn't act like my old blyetop did with the iacv delete. I guess my question is, where on earth do I start? Tps maybe?

might be the ABV valve stuck open.....also check the vacuum line to the OEM fuel pressure regulator

How can I test the abv? Also a bit of potentially pertinent information, the car has a walboro 255.

not sure ...i always removed mines and capped the holes off so it had max boost all the time...probably worn out the engines are pushing 23-24 years old now....think that pump is overkill...get a aftermarket pressure regulator and see if that helps

I'm going to get a hold of a fuel pressure tester and see what it looks like. If it is way out of whack I'll go that route. I'm also going to do the abv mod then clean it out to see if that changes anything. I'm going to start with free solutions and work my way up.

Update: When the engine is cold it won't idle at all. Once warmed up, it'll idle with the tps unplugged.

Just throwing some ideas out there. With TPS unplugged its probally "limp home mode:" rich + high idle that that would explain why it would run in that state. Have you checked manifold vacuuum and compared to spec to see if you have a vacuum or boost leak? Last time this happened on my gze I found a intercooler clamp came off. Once again just some ideas for you.

Many people find the 255 overwhelms the stock FPR. It's very likely your fuel pressure is too high at idle.