AE or PE adjustment. Which to adjust and when?

[damanx]

I've googled and read though quite a bit so far about AE and PE, but still have some confusion.

I have essentially started over in the tuning now that I have a transmission that is working as it should.

So, what I am currently seeing is a rise in the INT value on what I'd call moderate acceleration.

1. If I am at a constant speed with no change in the TPS and I encounter a grade, as the TPS stays constant, but the vacuum drops because of load, which one adds fuel?

2. If I am at a stop and then accelerate at a "normal" rate so to speak, I understand that the AE covers the initial lean condition of the throttle opening, but what covers the say 2-3 seconds of lean time after?

Attached is the BIN and a log file for example with times noted of the ride on the INT values:

Time: 10:10, 13:56, 16:19, 21:46, 22:13, 23:04, 26:15 (those are a few examples)

[brian617]

1. VE table

2. MAP AE in uSEC and VE table

[damanx]

Alright.

I added the BIN and a log file in 1st post.

This is a 1228062 ECM using the $4E.

[lionelhutz]

1. You won't get extra fuel above stoichiometric unless you enter PE mode. But, the engine can change volumetric efficiency and require a different amount of fuel to match the different amount of air. The VE (volumetric efficiency) table plus the closed loop feedback is used to calculate the fuel required to remain at stoichiometric.

2. PE covers the continuous fuel for acceleration, assuming the throttle position is high enough to enter PE mode. PE mode uses the VE table in open loop and then applies a factor in the calculation to be richer than stoichiometric. Otherwise the VE table is used to calculate the fuel.

Moderate acceleration should be closed loop but in a different area of the MAP than cruising. The int increasing probably could indicate that part of the VE table is a little low.

[damanx]

I read through a document online from Custom EFI's written by John Wilson that discusses the AE/PE parameters.

One specifically he mentioned, AE vs Map, did not seem to serve a purpose to him as he believed that the MAP value would not change unless the TPS changed.

I don't agree simply because of the fact that it appears to me that I can be at a cruise speed with no change in TPS and then the torque converter locks up and bam, I see the INT shoot lean, the vacuum drop, and the knock counts go up.

In addition to that, would not the vacuum drop when coming up a slight incline for example?

Is my thinking wrong on this?

I ask because what I am seeing is: the INT values shoot up to the 140's, BLM goes rich, RPM drops and knock counts climb.

That all makes me think the adjustment would be in the AE vs Map table to correct for that specific reason the INT goes up.

Now I can understand that you'd want a baseline for the VE cell where that is occuring, but should I do this in drive instead of OD?

Please ejumacate me....lol

[RobertISaar]

vacuum drops in those situations even with a steady throttle due to engine speed lowering(not enough torque being output to maintain speed). less RPM for a given throttle position will always result in less vacuum/lower MAP.

[damanx]

vacuum drops in those situations even with a steady throttle due to engine speed lowering(not enough torque being output to maintain speed). less RPM for a given throttle position will always result in less vacuum/lower MAP.

Makes sense, which make me wonder why he'd write what he did.

[lionelhutz]

I thought it was AE vs delta MAP, or more specifically, the extra fuel applied depends on the rate of the MAP change. The slow MAP change due to the engine load changing when coming to a hill should not even apply any AE.

Also, you posting about the integer still working and BLM values changing indicates the engine is in full closed loop fueling so it was not applying any AE or PE. The PCM has to be open loop to applying either AE or PE fuel.