lean condition code

TDCRacing · 05-06-2008

after having the battery disconnected and installing headers and rockers...my ltft's where at like 16 at idle.and part throttle. at full throttle my ltft and stft were locking in at .08 because of the maf tune that i did before the parts install. Any way i threw a lean codition code on bank 1....I do have a fairly small vacume leak under the throttle body but i cant imagine that this could have caused the problem...any input??

do i have to do another maf tune after the battery has been disconected?? wouldnt seem like i would have to because disconnection the battery doesent affect the air flow in the maf but im just wondering why my ft's are like they are

Could the relocation of the o2 sensor be the cause?? (pacesetters)

Thanks for any help

TDCRacing · 05-06-2008

by the way egr is gone for the fsic

**Reptile** · 05-06-2008

That small leak is what's doing it....sometimes a pinhole in a line can cause the issue.

**Zef_66** · 05-06-2008

Fix the leak. You can't troubleshoot a car with known problems. Especailly problems related to the symptoms. If you fix the leak and you still have issues, then look further.

But FWIW, you said you did a MAF before the parts were installed? If you installed rockers and headers, you majorly changed the performance of the engine. You need to do a VE tune and MAF tune after you install the parts. While the vacuum leak will affect the trims like you said, the lack of a good tune for your engine and mods will also make a huge difference.

**Sabrewings** · 05-06-2008

Originally Posted by Zef_66

You need to do a VE tune and MAF tune after you install the parts.

I guess I need to learn about tuning since I don't even know what VE and MAF tunes mean.

TDCRacing · 05-06-2008

Yea after I read some more i figured that was probably it...i will fix it,thanks

**02BlueGT** · 05-06-2008

Originally Posted by Sabrewings

I guess I need to learn about tuning since I don't even know what VE and MAF tunes mean.

VE is when you tune with the MAF unpluged or de-activated

MAF tune is ???? not sure havent gotten my tuner yet

TDCRacing · 05-06-2008

simple terms for maf- you are basicly comparing the actual air flow that is comming through the maf in hertz vs. the projected amount by the pcm. Bigger tb's cold air intakes ect can affect your maf tables and cause them to be off.

Basicly you open up your scanner to the maf hz histro and drive around trying to hit all of the cells.It will be giving you numbers like -5 and +5 in all of the sells that you hit. (this is the actual amount that the pcm is pulling/adding from this cell) after all of the cells are hit on the histro on your scanner you open up the editor and copy the maf table from the scanner to the editor by clicking copy-paste special-multiply %. you have to do that about 3 times for the maf hz histro table in the scanner to come up with all 0's (not adding or subtracting fuel from that cell)

Without a wideband only do maf hz's from 0 to 7500hz's

Example- if in cell 7500hz on your scanner in you maf histro you have a trim of -5....When you copy-paste-special -multiply by % it is taking that -5 that you pasted in there from your scanner and multipling it by that amount(actual airflow) vs. the (stock value) amount that was in the pcm. Wich would make your fuel trims zero in that cell.

GEt it?? ok so it's not so simple lol

If any one has some questions let me know and i will try to explain it better

**Sabrewings** · 05-06-2008

So, you just take what the computer was doing on its own, and setting that as the default trim?

Makes sense.

I just got my DHP PT today, but I gotta get the Keyspan adapter. I thought they guy I bought this off of had one, but turns out he didn't need an adapter.

TDCRacing · 05-06-2008

Originally Posted by Sabrewings

So, you just take what the computer was doing on its own, and setting that as the default trim?

Makes sense.

I just got my DHP PT today, but I gotta get the Keyspan adapter. I thought they guy I bought this off of had one, but turns out he didn't need an adapter.

you take what the stock pcm is programmed with and change it to what is actually happening...yes...that way at wot your ft's will lock in at zero...witch means no corrections are being made...at idle and some pt they will be inconstant witch is normal