Unfortunately the TW sensor is no longer available from honda for the EW or D15A engines.
However I found several after market ones over at Rockauto.com. Just make sure you get the one with the two small pins in the plastic plug. The large single terminal one is for the gauge on the dash. They are reasonably priced from $11-30.
I'm also looking into using one from a later Honda that isn't discontinued yet but want to make sure it will work before dropping $50+ on a new one. I prefer factory Honda parts when ever posible even if they are for a different car.

Just had a problem like this with a friends Si hatch. The owner of the car and I bolth had head aches from trying to figure this one out. The problem had been intermitantly happening over about a two month period. Running like crap and no PGM-FI light. We swapped out the distributor, ecu, main relay, ignition switch, coil, fuel injectors, throttle body, map sensor, plugs/wires and the car was still running like crap.
I told my other friend who has been a Honda mechanic of 20+ years what was happening and what we had replaced. I think it took him 2 sceonds to ask if we had replaced the coolant temp sensor (the one with two wires)? As soon as we did that the car started easier than I have ever heard and never skipped a beat. It seems that the sensor would periododically tell the ecu that the engine was as cold as it can get -40 and would compensate by adding a lot more fuel into the mix causing it to flood the engine untill it would bog down a die.

Local guys rule!!!
This guy is the real deal. I see him hard at work boxing up stuff to go out the next day when I get off work in the wee hours of the night after my second shift. Then he's back at it in the morning to ship things out before searching for more parts and pieces. By the way Danny stop calling me so early, I like to sleep in. LOL.
This guy works hard to find the parts to keep our cars looking good and on the road.
Oh ya, don't think that his knack for finding parts ends with your 84-87 Civic/Crx or 1st gen Teg although that's what he specializes in. He finds stuff for other old Honda classics too. He has even found me a few parts for my old 75 Civic 1200. If you have another old Honda car chances are he could help find what your looking for it too.