97 850 T5. swapped ecu from an s70 t5. Car will not start. switched back to stock. still will not start.
Fuel is getting to rail and making pressure, but the injectors will not fire.

 

If the injectors aren't firing it's likely the coil isn't either but you should check and let us know.

You should try to get a hold of an OBDII reader and see if you can pull any codes.

 

If you have spark, you should try starting fluid to see if it will run for a second or two on it.

 

OBDII showed no codes.
It ended up being the top left fuse (I forgot what they called it) blowing, I think as a sort of theft protection.
I remember when working on Audi ECU's, you have to lock the car, "arm" the alarm(lock twice), and then unlock all doors (unlock twice) all with the key to be able to start it after removing the ECU. After blowing a few more fuses I tried this. And it worked!

My 850 T5 has a 16T and white injectors, so i thought swapping ECUs might just work....in hopes to try and gain that extra "17hp" lol. Ecu swap threw "ecu failure" code only after leaving idle. it still ran fine, but didn't notice any power gains so I swapped back because i don't like CEL lol. Trans ECU kept the car in 3rd gear. No "arrow" light though, so i thought that was odd.

I just hope if anyone else is stupid enough to try this, they can find this easily. I spent a good 2 hours on google trying to find ANYTHING even remotely related to the subject, and found nothing.

But that was it. Ecu swapping will blow a fuse, cutting spark and power to injectors, if you do not follow that procedure.
Again, that procedure is: Manually lock the car twice via driver door, then unlock the car twice.

Crazy how little things can cause such huge problems.

 

Did you disconnect the battery before you pulled the ECU?