3800 engine starts, idles real rough, and stalls after 15 second

[Matteo]

Hi,

I'l explain how everything started:

The harmonic balancer on my Olds Delta 88 1988 needed replacement (completely separated). I replaced it with the correct one for the vehicle using proper torque. Restarted it and the engine turned but did not start. Fuel pump works. No spark.

Took a look at the crank sensor and saw that it was scuffed by the balancer locator rings. Decided to change it, verifying the spacing was correct.

Now it starts, runs really rough for 10 to 20 seconds and dies out.

Changed spark plug wires after seeing that one plug at the distributor end was more worn than the others, suspecting a problem there. Still starts but stalls after running very roughly for 10-20 seconds.

There is also some black smoke coming out of the exhaust after a few seconds of running.

This may have been there before but there seems to be some smoke coming out of the EGR unit. The computer had given a "check engine signal" for this unit a few weeks before but the problem had gone away. I only have a signal "12" when in diagnostic mode indicating that it's in diagnostic mode, but no other codes.

Any ideas on where to go next?

Thanks,

MH