Michael02hawk

iTrader: (26)

I'm new using the HP Tuner scanner & software, and I'mj trying to figure out why I get some surging right after start-up before it finds its idle.

In the log, I'm seeing when my rpms swing low the MAP is high and vice-versa.

Any thoughts as if the 2 are related?
Also, if anyone who knows what they are doing, wants to take aquyick look at my logs, let me know! :-)

thanks

jimmyblue

iTrader: (11)

MAP high means more air, more torque and this leads an RPM
rise. If it were oscillating steady the two ought to be about
90 degrees out of phase. But of course there is also lag to
the system.

I have been messing with this ever since the cam swap and
to me it seems like it's low RPM misfueling at the bottom of
it all. But by the O2s my fueling is dead on. I see it get a whole
lot better after a short while, but right after startup there is a
big discrepancy between commanded and actual AFR. What
I am suspecting is that it's residual overfuel from the startup
that is slowly boiling off the cold heads, adding to the fuel
commanded until it's all taken off.

If there's a better theory I sure could use one.