hi, i have swapped an s4 engine into my fb, but it takes forever to cold start. like, you have to hook it up to a charger or another vehicle via jumper cables and crank forever to get it to cold start. hot starting is good. i know the engine is good since it was rebuilt just before it was put in the car.

my question is: someone mentioned a starter signal wire that should be connected to a wire for the ECU. i dont believe this wire is connected, does anyone know which wire is the correct wire on the ECU so i can hook it up to tell the ECU its starting? i believe that may fix my starting issue...

 

just to be clear, there is a wire from the ignition switch to the starter, to turn on the starter.

there is also a wire from the start pin on the ignition to pin 3B of the ecu that tells the ecu the key is in "start" and then the ECU has a set starting map that only uses coolant temp and rpm. its a black/blue wire stock.

 

The one for the ecu is the one i was looking for. Im about 98% sure i didnt connect it when i was doing the swap. It cranks but doesnt like to start cold. I belive if i connect that wire, itll start much easier lol

 

If that was the case it would seem like it wouldn't start at all

 

the "start" pin turns on a different map than the normal one, it adds more fuel than the normal one

 

Ahh ha, now that makes sense

 

It does eventually start, it just takes a whole lot of "crank and sit" and eventually itll sputter and start. Im thinking it needs that start map, especially for cold starts

 

Did you figure what wire this was? Im trying to simplify and remake my harness and looking for that wire