idle RPM and IAC counts are not responding

[mmigacz]

Eaglemark:

This isn't a stern drive (I/O) transmission. Its a velvet drive, which is a small automatic transmission that only shifts from nuetral, forward and reverse. Its a 1:1 gear ratio. I ran this engine set-up last year with a Holley 600. Idling at 850 isn't an issue when you shift into gear. I do have an exhaust riser that will except an oxygen sensor. Currently, I am tuning everything with a wideband. I understand that my VE table needs alot of work, but working on the idle was my first step.

I appreciate the feedback. When I'm done looking through your suggestions, I'll most likely have some follow-up questions.

Steveo:

This is a wet exhaust, but the O2 is in a location that does not get wet. The O2 bung passes through the water jacket, into dry exhaust chamber. The mixing of water and exhaust happens abount 12" after of the O2 bung. I'm probably going to add a narrow band for closed feedback in the future. For now, I want to get it dialed in with the wideband.

Wouldn't the IAC be beneficial when shifting from nuetral to drive and vise versa?

[steveo]

Wouldn't the IAC be beneficial when shifting from nuetral to drive and vise versa?

only if the ecm has advanced knowledge that you're about to go into gear, otherwise nah. most marine engines only have one idle speed setting in gear or out. like i said earlier, a lot of control boxes will advance throttle a bit when you go into gear anyway.

[mmigacz]

Eaglemark:

I tryed your suggestions, and did get the IAC to lower to 20 steps, at the desired 850 idle RPM.

Thanks!

[EagleMark]

[mmigacz]

Eaglemark:

I have couple questions with regards to some changes you recommended. I had the below tables set up like:

before eagle.jpg
You suggested to change them to:

after eagle.jpg
Can help me understand what these changes are doing?

[EagleMark]

Well the TPS% is to keep it out of PE unless it's really needed... 80% TPS.

The other is to keep it closed loop idle. Which may have been an error on my part?