Ive been going in circles with this thing and in frustration i zeroed out all ae settings including constants and tables. Nothing changes. The BLMs continue to go rich, averaging 128 to 132,during acceleration they drop to the 108 area. Other than a tip in hesitation theres no real change in its behavior. Am i over looking something? I tried different bin files including a stock aujp and my regular bin based on axcn.

I would zero out the PE stuff first and try to work out some moderate accelerations fixing AE. If you are pushing the go-pedal to the floor then you are hitting the PE (Power Enrich).

You also might want to check the values in the upper map region of the VE tables... This is why it is a good idea to zero PE... fix the AE... then work on the upper map values... then add in a little bit of PE back in (when the other stuff is pretty close).

Thats what I am in the middle of doing right now and it is a little time consuming but I think I'm making good progress and not really having troubles.

I KNOW you already know this, part throttle tuning first, then the Power enrichment/AE stuff. Persoanlly, I would start over with the AUJP bin and work from the part throttle tune first, then mess with the PE/AE stuff from there if your having such a difficult time with your current tune.

In a stock $8D, you will not hit PE Mode unless two conditions are met.
1) TPS is greater than a value specified in a table (a 2D table)
2) MAP is greater than about 93 KPA (an XDF mislabeled constant)

Other than that you are running of the VE table without PE Mode active.

Thanks for the help everybody. The VE table was too big on the upper map settings and too small on the lower ones. It was nice and smooth vertically which is what had me fooled. Oh well live and learn.

Junkcltr

What is the actual name of that mislabeled constant in $8D and what is a better name for it?

Thanks

In the XDF I have it is called "Enrich Power Min. MAP " at address 0x85FF.
The stock value is 8.13 KPA. It really should be 101.7 - 8.13 = 93.57 KPA. It should be labeled Vacuum.

I'm looking at it now. This is the equation in the conversion tab.

-0.312500 * X + 80.000000

Is the "X" the constant value that we can change? If so then 8.13 would give a kpa of approx 77.5. Is this right?

There is a little more to it than that. It is based on the BARO reading. The example I gave is at sea level. If you were high in altitude then it would be more like 90.13KPA - 8.13 = 82.0 KPA to enter PE MODE. I leave the eqn. as is and label the term as Vacuum.

Hi junkcltr!



so you say, when i´m over a specified TPS value, eg 70.3% for an stock $8D, i will need to have at least 93.57kpa that PE can kick in?

please correct me, if im wrong...

regards

If coolant is less that 116*C, no TPS errors are present, engine is at sea level. Then yes, it needs 70% TPS (at 4800 RPM) and at least 93.57 KPA MAP to enter PE MODE.

If coolant is equal to or higher than 116*C, then the check for MAP greater than 93.57KPA is skipped. That is PE MODE is entered if the TPS condition is met.

This is for the AUJP code. Other $8D masks may differ. I have my TPS values set at 30% to 40% TPS to enter PE MODE. Once the MAP hits about 93KPA, the RPMs kick up a bit and the WBO2 drops down to the PE MODE 11.3 AFR.

Hi!!

very interesting...

is the setting for PE mode useful with 93.57kpa, or would it make sense to lower this value to lets say 85kpa?

also, does it make sense, to lower the TPS values (for kick in)?

thank you

junk, you previously mentioned that it is VACuum qualifier, which is true. Now switched back to MAP, which is distinctly different.

The only way to know what the MAP threshold is, is to also know what the barometric pressure is. With a VAC qualifier of 8 KPa, at sea level the MAP needs to be above 93 KPa (using 101 KPa as barometric, 101 - 8 = 93) for PE mode.

Someone in Denver will have a barometric pressure of about 84 KPa. With the same VAC qualifier of 8 KPa, now the MAP only needs to go above 76 KPa to qualify for PE mode (84 - 8 = 76).

RBob.

I am at sea level 101.7 KPA. So, for me it is 93.57 KPA and that is why I went back to it.


EDIT: 884+3, All of this PE MODE talk has little to nothing to do with your VE tables needing to be adjusted properly.

geez i thought that was the map value, so if i set mine to 80.00 assuming sea level than PE will be enabled at 21.70kpa ? damn

I once thought that also. I posted that info because I figured others thought the same. The XDF label is very misleading. It is like RBob said though. It is referenced to the BARO reading.

Yes, if at sea level and standard air values, and you set the CAL value to 80 KPA, then you will enter PE MODE when TPS meets the TPS vs. RPM value and your MAP is greater than (101.3 - 80) = 21.3 KPA as read by the MAP sensor.

I hear what you are saying...

What is the formula in the xdf used for (the one is listed in previous post)? The way you describe it makes perfect sense, its the xdf that doesn't make any sense...

Thanks

The eqn. you posted is correct. The XDF label should be Vacuum instead of MAP.

I played around with the 2D TPS vs. RPM table and Vacuum XDF constant to enter PE MODE earlier than stock. It is kind of like running an open loop bin most of the time but at low throttle cruise TPS, RPM, and MAP it runs closed loop. As I increase the throttle (and MAP) it enters PE MODE that has AFRs that are slightly richer than stoich and keep getting richer as MAP and RPM increase. It smooths out the non - PE MODE to PE MODE transition when rolling on the throttle. Quick throttle jabs are different in that they require some AE also.

In doing that, the engine runs stronger but also uses more fuel when you get into the throttle. I tend to be easy on the pedal when just cruising so I burn a little leaner than stoich (about 14.4 for 10% ethanol). It seems to run OK at that AFR at cruise. For more power it likes 13.5 and richer. For the PE MODE tuning I tend to stay slightly rich because of fuel quality varying. I let closed loop take care of the fuel qual. problem at cruise RPMs.

That is how I am running it now. Always experimenting so it may change if I find something else works better.

The light bulb just went off

You are saying that at 8.13 inches of vac or lower vac values will allow PE mode, right?

Nah, you are thinking 8.13 inches of vacuum. Vacuum here is read in KPA.

The best way to figure it out is this
1) connect a scan to the ECM
2) turn the key on, engine off
3) read what the MAP value is in KPA (that is your BARO)
4) decide where you want PE MODE to be active (call this PEMODE_KPA)
5) open the bin
6) change the Vacuum constant to (BARO - PEMODE_KPA)

Example:
car on, engine off your MAP read 100 KPA (your BARO)
you want PE MODE to come on at 60 KPA (what the MAP sensor reads on the scanner)
Change the bin value to 40KPA. That is, (100 - 60) = 40 KPA of vacuum

EDIT: For the question you asked. Yes, PE MODE will be active for 8.13 KPA or LESS of vacuum. At WOT you have zero vacuum if that helps make more sense. Slightly less than WOT you would have around 8.13 KPA of vacuum. ECMs are tricky in that everything is KPA. Where as most gauges are in-Hg.