Finally started engine and didn't have a cel on......but once its been running fir about 5 min .....it turns on displaying code 13....baro sensor.....this is on p 30 ecu.....so I changed it out with the stock p28 ecu and same thing happened..... I drove around or left it running for about 5 min...the cel then back on......code 13 once again.....anyone kno how I can troublEshoot this cel....?????

 

^^^b16^^^

 

seems you have 2 different ecu's with bad atmospheric pressure sensors (PA)
as they are integrated into the ECU, and the only thing that can be done according to factory service procedures is to replace the ECU as whole.
make sure you have correct parts and install techniques for your swap.

 

No, both ecu are un working order have tried them in other cars and seem to work perfectly.....I have no clue where to start looking for a solution.....I've seen other posts but it never gets to how they fix the problem.......

 

you may just have a bad ground or a 12V wire to the ECU.
Check all the wireing is good and if you have any butt connectors in the system solder them and use shrink tube.

 

How would I have that 12V wire to the ecu.....any ideas ?

 

the ecu should have a switched 12V wire and at least 1 constant 12V wire as well as multiple grounds some of the grounds only work part of the ecu.

 

Anyone have an ecu pinout diagram for a 93 civic Si ?