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.

[damanx]

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.

AE vs delta Map is what I think it would be too because I've seen the vacuum drop because of load while the TPS stays the same value.

I'm not too educated on what parameters are only in use during open loop and those during closed loop.

If AE and PE are only in effect during open loop, the I can only assume that for the INT going extreme on the high side during closed loop means that I need to be looking at something else.

Not to throw a wrench into the equation, but I'm not 100% sure of the ethanol mixture of the gas I use from station to station. I also think that I still have the Stoich parameter at 14.7 in the BIN, so that might the sole issue there. If I recall correctly, I believe EagleMark once told me that I probably want that value at 14.13.

[Dr_Grip]

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.

I know I am still a n00b regarding fuel injection, but AE is needed for an engine to work properly no matter whether it's in open or closed loop: The moment the throttle is opened, an extra splash of fuel has to be injected proactively so the engine won't lean out before the o2 sensor even detects it.

[damanx]

I know I am still a n00b regarding fuel injection, but AE is needed for an engine to work properly no matter whether it's in open or closed loop: The moment the throttle is opened, an extra splash of fuel has to be injected proactively so the engine won't lean out before the o2 sensor even detects it.

I've not been able to find anything that states in stone so to speak that AE is open loop only. Found plenty that concur that PE is open loop only.

In any case, it appears that I am seeing a slight lean spot during "normal" acceleration, especially when the TCC locks up.

[lionelhutz]

Geeze, closed loop uses the O2 sensor and the O2 sensor is a narrow band sensor that ONLY works at stoichiometric. So there is no way the ECM can run the fuel richer than stoichiometric while in closed loop and actively adjusting the INT and BLM.

[Byron454]

I believe that a lot of the confusion about AE and PE has to do with the lack of experience with Tuning an engine VS tuning a fuel injection system. The engine is what you need to make Happy. Think about how A carb makes a proper air fuel ratio (or at least close to proper air fuel ratio) happen? AE is pump shot PE is power valve. Cruise is main jet. idle is mixture screws. Make the engine Happy.

[steveo]

I've not been able to find anything that states in stone so to speak that AE is open loop only. Found plenty that concur that PE is open loop only.

it's impossible for an enriched state to be truly closed loop, as responding to a narrowband o2 signal inherently puts you OUTSIDE the range of enrichment beyond stoich, but it may use the current trim data as a base calculation, temporarily disabling learning. i think the confusion is that in your logs during AE or PE, the engine status flags may indicate a closed loop state, this is normal.

there might be non-ae tps variables that say 'add x amount of fuel for this particular tps delta in closed loop', but that's not AE, it's just a measurement of how much extra fuel might be necessary to maintain a target afr. it's not enrichment.

[Dr_Grip]

it's impossible for an enriched state to be truly closed loop, as responding to a narrowband o2 signal inherently puts you OUTSIDE the range of enrichment beyond stoich, but it may use the current trim data as a base calculation, temporarily disabling learning. i think the confusion is that in your logs during AE or PE, the engine status flags may indicate a closed loop state, this is normal.

That makes sense and was about what I was trying to say.