I have a 92 integra ls that i recently did a b20b swap and gsr tranny on. I finally got everything running smoothly for the most part other then random exhaust leaks and whatnot, but when i swapped motors i had to change the injectors back to the ones that came out of the original b18 because the plugs on the wiring harness wouldn’t plug into the injectors in the b20. After i got everything running smoothly i decided i wanted to go back to the original injectors that were in the b20 and read on a forum that you could simply cut the plugs off the harness and splice in the right plugs to fit the original injectors that came in the b20. So i did just that, i made sure to do 1 plug at a time, made sure the wire colors matched up perfectly spliced and soldered the wires to make sure i had a good connection then taped them up and put the rubber boot back over the wire where i spliced the new plugs on. Once i put the injectors back in the fuel rail and hooked everything back up the car will start, but it won’t idle for crap, sounds like garbage, and even mashing the gas all the way to the floor it will not rev over about 3200 rpms. I have no idea what the problem is as i changed nothing but the plugs and back to the other injectors. Someone told me to switch plugs back again and put the b18 injectors back in, i tried that and it does the exact same thing still. When i get the car started and idling, i can unplug 3/4 injectors and nothing changes in the crappy idle, however when i unplug 1 specific injector it instantly kills the motor every single time. Anyone have any idea what the problem is and how i can fix this as im running out of funds to pay a professional mechanic to come take a look at it for me from the tons of cash i’ve dropped into this motor/tranny swap as well as body parts and everything else as well. I’m by far noways near a good mechanic and this is the very first motor swap i’ve ever done by myself with my brother giving me a little help as far as lifting and dropping motor/tranny’s in the car. I’d really like to get the car back on the road in the next 3 days because i have to start back to work in 3 days which will be hard without the car running lol. Thanks in advance for any and all help or tips you give me. Any additional information you may need about the car or methods i used in trying this let me know and i’ll give whatever info needed to try and get this figured out. I’ll be checking this forum about every 10-20 minutes over the next couple days for updates as well so i should respond promptly unless i’m sleeping. Thanks again 
You have 3 dead cylinders and only one that is actually working. Check your splicing/soldering. Break out your multimeter and check for voltage at the connector for each injector (yellow with black wire). then check for continuity for each injector wire (red, blue, brown, yellow).
Everything looks to be good so far, i also had a friend swing by and make sure i was using the ohm meter properly (as i rarely use one) and he said everything looks good as well. So now i’m back to square one again…
Any codes on the ecu? If not, time to check the timing plus timing belt alignment. Check your distributor, cap, rotor, plugs, plug wires, timing, and cam gear timing marks. After that and no luck, time to do a compression check.
Ecu is throwing 1 long blink and 6 short being a 16 i’m sure which is injectors. Already checked timing belt alignment, brand new distributor/cap/rotor, just replaced plugs 2 days before starting this injector plug rewire, same with plug wires, had my brother check timing to make sure i was right about it being good. only thing i haven’t checked you listed was compression as i don’t have the required tools tonight, friend of mine is coming over tomorrow to check compression for me but i’m sure it’s something with the injector wiring still. i know the injectors are good just no idea why it’s throwing a code and not running right…this is by far the most trouble i’ve ever had with anything this simple.
Well there is not much to the fuel injectors. Ecu sends a negative signal to the injectors via a wire (red, blue, yellow, brown). Positive voltage is via the yel/black wire. And you said you checked everything and it’s good. The only other part is the resistor box but that’s with obd0…
Well i managed to get everything fixed today, i have no idea how but both sets of injector plugs were bad. No idea how that happens considering they worked fine before doing this, and they even tested fine with an ohm meter. but i picked up a set of brand new ones, spliced/soldered them on and everything works like a charm now. By far the biggest pain i’ve had in this swap so far and it was all something simple lol. I’m just glad to get it back up and running fully.