Can someone explain PE on a 3800 SC engine?

[Jay@HAP]

Let me start off saying I understand what PE is, what I'm trying to figure out is how the adders/multipliers work on this PCM. I've not tuned one of these before. A good friend of mine has one and I've been playing around with it.

He got a mail order tune for it and its stuupid rich. I logged it this afternoon (didn't have the WB hooked up)to get an idea of where it's at. It's probably 20% rich anything above 5000hz and knocks everywhere(don't know if it's real yet or not) I can only assume that its that rich at WOT.

Looking at the PE fuel base vs ECT(which I'm guessing is the main table) and the multiplier tables; PE fuel adder vs TPS and PE fuel adder vs RPM vs time.

What I'm trying to figure out is, for example, at 176 degrees coolant temp, the commanded AFR(PE vs ECT) is 11.9 but in the log its commanding 11.1. Where is the .8 of enrichment coming from?

I'm not looking for someone to tune this thing. I'd just want/need to understand how this works before I go changing things.

Thanks for any info.

J

[5FDP]

The lower number is coming from the RPM adder. It lowers the EQ ratio by whatever value is in that table at whatever rpm and time in seconds.

The longer you are in the throttle the lower the EQ ratio will drop from the commanded 11.8-11.9 AFR. If you want to make it simple just zero that entire table out and only use the base AFR table like a LS engine.

[Jay@HAP]

The lower number is coming from the RPM adder. It lowers the EQ ratio by whatever value is in that table at whatever rpm and time in seconds.

The longer you are in the throttle the lower the EQ ratio will drop from the commanded 11.8-11.9 AFR. If you want to make it simple just zero that entire table out and only use the base AFR table like a LS engine.

That's the part of the equation that I wasn't able to figure out.

Thank you for the reply.