PE mode

[turbo lcc]

What is PE Mode?? and how does it work??

[Redline Motorsports]

PE mode is Power Enrichment. It is used to provide fueling at WOT. WOT occurs after several other tables have met there values.

This is the table most often used to tune WOT.

Howard

[SSpdDmon]

Not just WOT.

Power Enrichment provides extra fuel for higher load situations. It's actually enabled at 65% throttle (or sooner) depending on RPM. Normally, cars operate in a closed-loop fueling mode where the ideal air fuel ratio is roughly 14.7:1. The reason why it's ideal can be fairly complex, so I'll ask that you take my word on it. This closed-loop operation simply means there are sensors in the exhaust that measure the AFR, which provides feedback to the PCM. Then, the PCM will adjust fueling based on those measurements. The process is repeated over and over again (like it's in a loop).

As the demands on the engine increase, more fuel is required as engines typically make more power with an AFR between 12.2:1 and 13.2:1. But because of the type of sensors in the exhaust (only accurate at measuring 14.7:1), the PCM can't rely on the feedback it gets from them. Therefore, it goes into an open-loop state (PE). Fueling is now more linear. The PCM commands what it will for AFR without knowing if it's right or wrong. The only adjustments to commanded AFR's in PE are made by the PCM observing the trend it has been seeing in certain parts of closed-loop operation. In other words, if the PCM sees the need for more fuel in closed-loop, higher load scenarios, it will carry that percentage of extra fuel over to PE.

I'm tired typing now, so I hoped this helped. If you check the stickies in the PCM forum over at LS1tech.com, you'll find a ton of info on how the stock PCM works and different ways to tune for almost any issue you can come across.