Hey this is my first post here so sorry if i’m doing it wrong but i’ll just go straight into the meat and potatoes. I have a 93 Del Sol with a turbo B18B1 swap. I recently started putting in a new fuel system. I did fuel pump first. after installing the fuel pump, the car idles poorly (as to be expected) but after I installed that, I installed a new (AEM) Fuel rail, (AEM) fuel pressure regulator, and (Fuel Injector Clinic) 650CC injectors. (we also had to wire on new pigtails for the injectors) At first, after installing all of this, the car would start, and idle very poorly (we didn’t have the fuel pressure regulator adjusted) we took a break for 15 minutes, came back and the car would no longer idle. we adjusted the fuel pressure regulator closer to the stock 43.5 psi to no avail. we couldn’t get the car to idle again. the only way the car would run is if we started it with the gas floored and slowly let out. but even then as soon as we’d let off the gas, the car would die. We checked all the O-rings on the fuel rail and injectors and they all seem to be good. I am wondering what could be causing it to die? I’m aware that it’s very out-of-tune but i’m concerned that it used to idle and now won’t. Do you think I just need a tune? could it be the IAC valve? It’s just weird to how it worked for a second only to stop working 15 minutes later. also if it helps, the car is not maintaining fuel pressure after priming. it will prime and slowly drain of any/all fuel pressure. but I believe this is due to the fuel pump i put in (Walbro 255) not having a check-valve but I could definitely be incorrect about that

 

What size fuel injectors did you have BEFORE you installed the FIC 650's ?

 

just the stock B18 injectors, I believe 240CC

 

Your ECU doesn't know you swapped fuel injectors... and the adaptation can't pull the fuel back far enough by fuel trim alone to make it run reasonably well... the 650's are two and a half times larger than stock. If you had engine management, you could change the fuel injector size and personality (latency, battery offset, dead times... whichever you prefer to call it) in the tune and see how close things are after that. In the end, you will need to clean or replace your spark plugs because they are good and fouled by now... fill the tank with the fuel you intend to run, and tow the car to the tuner.

 

Yeah I assumed as much. was just confused because initially the car would idle. I’ve checked my plugs and they’re fine (they were brand new) I knew it needed a tune either way. just wanted to make sure everything was as it should be. thanks