Idle too high. How do I adjust

[Eric Bryant]

> From: Dan Griffin [mailto:slowfatslug at hotmail.com]
> Subject: Re: Idle too high. How do I adjust
> 
> 
> Bottom line: Does ecm use vss to determine eng. load?? If so 
> I dont see how
> a car/truck ecm could be made to easily work on a boat..I say 
> 14.7 to 1 is
> way to lean, even at steady cruise, ( 19-23 mph hull just 
> planing)...eng
> load for a car is much less...If only map, tps and rpm are 
> used I think I
> could see how this might work though...

Excuse me if I say something really dumb (I'm a lot more familar with the
'8051 than I am with any of the older TBI stuff).

I don't think the VSS is used to determine engine load - it's used to set
the IAC position, so that closed-throttle engine speed can be adjusted for
the vehicle speed under xxx MPH.  This seems more important in manual-tranny
cars, and I can't really see why it'd be all that important in a boat.   

If indeed there's a problem with the way that the boat loads the engine, and
if maintaining stoich under "normal" operating conditions is undesirable, it
seems relatively simple to change the program so that the engine is
operating under power enrichment.  Extra fuel could then be added as
appropriate to the throttle position under these conditions.  There might be
a better strategy for this, too - as I said, I'm not that familar with the
TBI stuff.

Eric Bryant
mailto:bryante at ghsp.com
http://www.bryantperformance.com 

 
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