I newly rebuilt my 700sci's.

When i went to fire up one of them for the first time, it is idling rough and black smoke.

Fuel pressure is 61psi and no codes thrown on the computer.

Checked coils all ok. Injectors all cleaned and tested . were fine.

Swapped sensors with my other engine which is working fine and problem still exists.

Please do let me know what im doing wrong or where I should look.

Thanks

Black smoke=fuel.

Why is fp 61? Is that where it was tuned to run?

No but I’ve read the 700sci runs between 60 and 65psi

I would start by pulling the plugs and see if one of them is running a lot richer than the others. If so then you need to have that injector checked again or just replace it.

I don't know those fuel systems to give you any other advice but as an engine builder I would say you should not run it any longer until you find the problem. A lot of extra fuel will quickly kill new piston rings.

Maybe switch ECM's

list the sensors you have switched.also,can you read the data on the engine thats running rich?

Yes everything is fine.

as Bill said, pull the plugs. if one or two are rich then it is an injector problem. if all are rich then an ecm or voltage problem. low voltage to the ecm or coils can cause this or a bad ground that keeps the coils from charging or ecm from operating. at around 10-11 volts the ecm gets very unhappy.

So, are you saying it was not tuned at 61, but now you are now running it at 61? I'm a little confused.

I have not tuned anything

engine was rebuilt at factory spec