Does anyone out there know what the normal load percentage should be at idle for a 99 5.4, my truck at idle sits at 27% load and that doesnt sound right to me. So i checked a buddy of mine truck and his was sitting at 2.7%(he drives a s10 dont kno if that makes a difference). any comments would be appreciated, thanx

 

How are you getting these numbers? I've never heard of load percentage before.

 

Probably has a ScanGuageII like I do. I've seen it on the display but don't really know what it is derived from.

 

I have a code buddy, its one of the option in the code reader that tells u what percentage of load ur engine is under. It just doesn't seem right that under idle my engine has so much. I would think that at idle ur engine should virtually have no load.

 

According to my Gryphon idling I'm usually 16-17% load. 27 does sound high. I take it you put the code buddy on there to get trouble codes because something was wrong, so was there any codes or you just put it on to look at the gauges for fun?

 

According to my Gryphon I'm running about 18% idling at 650 rpm.

 

I see 22% at 700 rpm idle with a Scangauge2.

 

i didnt have any codes, i was just lookin at it one day bc i was bored lol. Any clue as to what would be putting so much drag on my engine??

 

Well I don't know about gasoline engines, but the Cat 3412 Natural Gas engines I have at work I can tell you how much load is on it and give a rough horsepower output by reading the manifold pressure. As the engine works to suck in air and fuel it collapses the pressure in the manifold creating a vacuum (if it's a naturally aspirated engine), or it increases pressure if it is a turbocharged or supercharged engine (the reason why those things increase horsepower so much). My guess would be that the computer has some sort of vacuum gauge hooked up to the manifold telling it how much of a vacuum it is pulling and how much air/fuel it is bringing in.

If the above is true (don't quote me), I would guess it may be caused by a restricted intake (plugged air filter). If your filter is plugged it would cause your engine to work harder to pull in air, thus creating more of a vacuum. It's worth checking anyways.

 

The PCM uses input from the MAF sensor along with Baro readings and other inputs. I would try cleaning the MAF to see what that does. If you can access the Baro PID compare it to a local reading to see if it is off.

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