Quote Originally Posted by Mikey G View Post
Hi Fast355 Your Marine 395 cam has somewhat similar duration to my cam. I had to remove my intake manifold to swap out the HEI over to the L31 distributor to provide the CPS. the intake ports were heavily stained with fuel/carbon deposits al the way up to the TPI runners. I thought this to be excessive. This past summer, the engine had done a lot of idle tweaking with the OBDI set up. I understand big cammed engines have no business sitting at idle for extended periods of time. I do have a few questions regarding your set-up. - What vehicle is this engine in ? -or going in? - What RPM did you get the idle to settle at? - What have you done to the idle tables to compensate for the false lean condition the O2 sensors would read at idle ? - Are you running open or closed loop when idling? - Does the sequential injection and COP offer any help with a high overlapped cam at idle ? If there are any others who have comments to offer - please do. Thanks in advance. Cheers. Mikey G
It is in a 1997 G1500 Express van.Idle is set at 700 rpm. I only idle it that high because of the 25% underdrive pulleys. Very few changes to the 02 sensor tables. I did have to make some minor changes to the proportional gains due to the long tube tri-y headers. It actually runs slightly lean when you monitor it with a wideband. The plugs stay clean and with the COP running stock .060" plug gaps I have tun it as lean as 17:1 without misfire.Closed loop at idle (I am in closed loop in about 45 seconds)Sequential injection does help because you can set end of injection timing to correspond with cam timing.My cam is relatively small and has no problem idling for long periods of time. I let it idle for about 4 hours straight last winter on a roadtrip to Ohio. Got into a storm and it was crazy cold, pulled off for a few hours and slept a while.