Quote from 0LD5455 on March 7, 2021, 2:26 pm

I've done a lot of searching and found good advice for getting my 400hp unit running pretty well on my Olds 455. It runs well in all conditions, idle, tip in, cruising WOT. One issue I still struggle with is cold starts. When I crank it will fire then die then on a re-crank it will fire up and run fine.

When warm it starts and runs fine.

I started by verifying that voltage is not dropping on crank. I've turned off the prime shot and that helped with warmer starts. I also have reduced the cranking and after start fuel in the cold cells as it seems like it's over fueling.

I noticed in a data log today that during crank and for a few seconds after it sets a 55 and 105 error code. I believe these are for the 02 sensor. Is it normal for these to set during crank?  After running for a few seconds they clear and don't seem to return.

Thanks in advance.