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Calculated Engine Load with AutoEnginuity Scan Tool
10-21-2006, 12:46 AM
I'm trying to trace down a lobe in the idle of my 2001. I bought an AutoEnginuity ScanTool and am learning how to use it.
Quation: Does anyone know what the Calculated Load at idle is supposed to be? Mine is rating about 22-24% which seems high because our Buick only ranks in the 10's.
10-21-2006, 01:11 PM
Engine load is a calculation, and there are a lot of things that go into it, some of which I do not know about.
Two biggies are MAF sensor flow compared to theoretical maximum flow (otherwise known as volumetric efficiency).
If the engine can theoretically flow 40#/min of air, and is only CURRENTLY flowing (measured) 10#/min then the VE is 10/40 = 0.25 or 25%.
However, that LOAD (VE) is only one part, temperature, throttle position etc also play a role - exactly how I have no clue.
10-21-2006, 02:48 PM
Thanks for that. My other question would be...
"Does anyone have any numbers from their car that indicate the calculated load at idle?"
I noticed that the typical 'actual load' things will increase calculated load....such as turning on the heater motors and bright lights, etc. Turning the power steering while stopped pushes it from the 30's to 60's but I have that "increased rpm with power steering" problem that I wrote about earlier.
For curiosity I plugged in to the Buick Rendezvous again today and it has a calc load of 4-5 at idle. The Windstar is still around 24 at idle. Does anyone have some numbers from their WS that they can post?
I was also wondering whether things like the failing idler bearing or a failing alt bearing play a role? My alt seems find but there is a terrible sound that causes vibration in anything that touches it....but it seems fine if spun by hand. Just wondered if actual meachanical load will raise the calculated load.
10-21-2006, 06:42 PM
if any thing thats worn metal wise could cause a load. Friction can cause a load.
Although small the worn pully could cause a load.As for the belt remove for a few minutes on a cool engine and see what you come up with. Also the buick you speak of sound new so its optium performance would be greater. So the load would be less.
10-22-2006, 11:55 AM
Good point about the Buick, it is in better condition too.
Last night I picked up the Ford enhanced module for the AutoEnginuity scan tool software and while I was playing with it I noticed the load was down to 15%. I don't know what I can attribute that to. When I get time I'll have to switch back and forth between enhanced and generic and see if there is any difference.
As for those other failing bearings I'll have to get them fixed too :)
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