why do the injector pulse widths get shorter the higher rpms u go? is it because they have less time to fire because the engine is rotating quicker? wouldn't this cause u to have less fuel when u actualy need more fuel?

 

have you looked to see if the decimal point is moving. what kind of scanning software are you using ?

 

http://www.fbody.com/members/david88...tool/Book1.htm

here is the data i have gotten from the scan tool. its pretty crappy as it only records for like 3 seconds or so.. but it gets the job done

 

i dunno maybe the scan tolls istn working correctly. ?? but injector pulsewidth will fall off as the fuel demands of the engien fall of. typically the engine will begin to run out of air at HIGHRPM so you will need less fuel.

 

i thought the motor would get more air at a high rpm due to the fact it's sucking more in and your going faster.

 

after the engine reachs peak TQ it will typically flow less air. go read some dyno sheets with cfm consumption charts youll see the trend.

 

the MAF still showed an increase in airflow as the pulse width was decreasing.. look at link above. now the increase in air flow wasn't as great as it was at lower rpms. but it was still increasing..

 

Keep in mind that your fuel pressure goes up as the throttle is opened, so it is possible, although mine doesn't.

 

The pulse width is corrected by the O2 sensor so maybe on low load, you just didn't need the gas to get the revs, and the O2 would go low, so the ECU would cut back on the gas.

On high load, as the engine reaches the peak power it cannot get enough air through the inlet system, the air gets less and less dense as the vacumn starts to increase again, so it cannot handle the same amout of fuel on each stroke. Hence the shorter pulses.

At high revs, the engine produces more power, because it fires more frequently, but after a peak it makes less torque because it cannot get enough air, unless you supercharge, and can burn more fuel at the high revs. That's my guess.