Pe mode WOT AFR's running lean

[baf2000_1]

Looks like I am running 11-12% lean. Notice the WOT 1:15 into the log. How can this be adjusted?

Thanks

[WS6FirebirdTA00]

I would advise you look over all the writeups and how tos before you do any more. This is done through VE/MAF depending on what mode you are in.

[baf2000_1]

Most of the writeups imply that PE mode is open loop. Correct? So this should be a VE issue? But after changing the VE for WOT there seems to be little effect , still a bit lean. Thoughts ??

[WS6FirebirdTA00]

are you in SD or running MAF?

[baf2000_1]

I tried both. With identical results. That is why I assume the MAF is out of the equation. Also, when I move the PE table richer both commanded and actual get richer but the spread is still 11-12% lean. Weird huh?

[ninobrn99]

get it down in SD as far as ve goes, then do the maf.

[WS6FirebirdTA00]

I tried both. With identical results. That is why I assume the MAF is out of the equation. Also, when I move the PE table richer both commanded and actual get richer but the spread is still 11-12% lean. Weird huh?

It doesnt matter, I just want to know what mode you are in. Did you fail the MAF or no? How much did you change the tables by?

[baf2000_1]

It doesnt matter, I just want to know what mode you are in. Did you fail the MAF or no? How much did you change the tables by?

The MAF was Failed over and she ran lean. I will do another scan...

[Main_One]

I'm guessing your airflow calculations are 11-12% low. You can fix this by upping your PE ratio, but some prefer doing it by fixing the airflow calculations. I would recommend getting that right as well, as that will possibly also affect your spark advance, among other things.

If you are not in SD, the MAF should be ruling your airflow #s above 4000 rpm. If you are in SD, then obviously it should all be controlled by VE table.

[baf2000_1]

I'm guessing your airflow calculations are 11-12% low. You can fix this by upping your PE ratio, but some prefer doing it by fixing the airflow calculations. I would recommend getting that right as well, as that will possibly also affect your spark advance, among other things.

If you are not in SD, the MAF should be ruling your airflow #s above 4000 rpm. If you are in SD, then obviously it should all be controlled by VE table.

Is there a 100% accurate way of determining if the engine ( LS2 ) is in SD mode?

[ninobrn99]

unplug the maf.

[[email protected]]

If the maf fails, it will use the VE table rather than PE. You will need to modify the primary VE tables in order to dial in the air fuel ratio.

Set the failed maf to 0, unplug the meter and dial in the entire VE table. Set the failed maf back to 1100, plug the meter back in and tune the maf. You need to ensure if you are in SD or MAF mode

[[email protected]]

Is there a 100% accurate way of determining if the engine ( LS2 ) is in SD mode?

You will want to fail the maf, then go into the DTC section to turn off the maf code, but still enable the MIL to let you know you are in SD mode

[Bill@HPTuners]

If the maf fails, it will use the VE table rather than PE.

Actually if the pe is still in use its still in use no matter what mode your in. Yes your part throttle & wot backbone is determined by the VE table but pe mode can still be active when in SD otherwise how would the computer know WHAT afr to go to

[[email protected]]

I meant to say the following:

If the maf fails, it will use VE rather than MAF table but the PE Table is your commanded air fuel ratio.

Correct me if i am wrong:
If you look under PE, it will tell you exactly what kpa the PE (maf table) will be used. The enrichment rate also needs to to be paid attention to. From my understanding this is a multiplier for fuel. A cobalt is .020 and a Vette is 1.00 if you needed an example
.

[Bill@HPTuners]

I meant to say the following:

If the maf fails, it will use VE rather than MAF table but the PE Table is your commanded air fuel ratio.

Correct me if i am wrong:
If you look under PE, it will tell you exactly what kpa the PE (maf table) will be used. The enrichment rate also needs to to be paid attention to. From my understanding this is a multiplier for fuel. A cobalt is .020 and a Vette is 1.00 if you needed an example
.

it depends on the vehicle & what mode your running in really, if your running in SD open loop you could be running on strictly pe(unlikely but possible depending on the settings), strictly OLFA(50/50 chance, but again depends on the settings), partly OLFA & partly PE(likely but again depends on the settings you enter but in stock form this is what happens) closed loop SD is a totally different ballgame, and all of this varies from one car to the next in reality...LS2's are different from LS1's and have several OLFA lookup tables, as are V6 cars, etc. So like I said it depends on the vehicle but if your talking LS1 what I've stated is pretty much the norm.

[chrisj6]

PE is only a multiplier. VE will control the base AFR if you have the MAF failed, and multiplies the base to get your actual. Same thing if the MAF is enabled and its in open loop.

Chris

[[email protected]]

PE Mult. determines the rate at which fuel is added to reach enrichment value (found in EQ Ratio .vs RPM)...basically a multiplier

EQ Ratio .vs RPM is your fuel look up table. For example having a value of 1.134 will be the following:
14.7/1.134 = commanded air fuel of 12.96 (which is used as a lookup table for both VE and MAF Tables)

If you are in SD mode, you will add/remove VE to match your desired AFR, which is commanded in the EQ Ratio .vs. RPM Tabe). If you are using the MAF Table, you will add/remove air to get your desired AFR, which is commanded in the EQ Ratio .vs. RPM Tables.

Yes, there are determining factors for every vehicle that modify these tables, and control what mode you are in such as the enrichment rate, when to use ve/maf tables, etc etc

[Bill@HPTuners]

If you are in SD mode, you will add/remove VE to match your desired AFR, which is commanded in the EQ Ratio .vs. RPM Tabe). If you are using the MAF Table, you will add/remove air to get your desired AFR, which is commanded in the EQ Ratio .vs. RPM Tables.

dont fall into the trap even I fell into once thinking SD & OPEN LOOP are the same thing...you could be in SD closed loop or SD open loop, obviously if your in SD closed loop your not going to be running on the OPEN LOOP FUEL ADDER table

[Russ K]

If the maf fails, it will use the VE table rather than PE. You will need to modify the primary VE tables in order to dial in the air fuel ratio.

Set the failed maf to 0, unplug the meter and dial in the entire VE table. Set the failed maf back to 1100, plug the meter back in and tune the maf. You need to ensure if you are in SD or MAF mode

The IAT sensor is part of the maf, so don't unplug the maf. Set the maf fail freq to 0. You will now have code P0103.

Russ Kemp