e38 cranking help

[ringram]

I had similiar issues with 230 cams, I had to command a lot more min idle airflow then stock. It was worse when hot. Increasing cranking air and min idle air cranking timing. and B1845 multilply that by -50% reduces hunting a lot. I would imagine being a big cube engine it would need a lot more air.

Yep pretty much exactly what Ive done. She eats shedloads of air
Im still progressing ok, so will post up if/when I get stuck

[calais-346]

Hi Ringram,

I was talking to someone about this sort of thing last week.

Have a look at B8062 and "REDUCE" the % value for the cranking. I haven't put a lot of thought into why this works, but it seems to help a lot with larger cams. I think the guy I was talking to tried values around 75% to start with, and then jumped to 50%.

The other table would be B5119. For some reason, GM decided to put some weired steps in the spark map for cranking. I removed the -VE values, added some timing as the RPM rose and smoothed the lot out.

Hopefully this helps a bit.

Simon

After going around and round in circles changing cranking idle air and timing, i tried this, i reduced B8062 cranking ve to 75% and now have perfect starting!

Safe to say i'm a very happy man now, i was getting sick of putting my foot on the throttle to start the car