BadManLS1

iTrader: (1)

I did some WOT logs with HP tuners today.... O2 mil. volts were from 935-950 on both banks and LTFT B1 was 6.3 and LTFT B2 was 7.8 . From what I have read that is rich right? How do you go about changing this and what should these numbers be? My mods are in the sig...thanks.

TimZ28

BadManLS1,

You cannot use the stock O2 sensor readings to determine that the car is running too rich. I tuned a 99 Z28 over the weekend that was at ~13:1 per the Dynojet wideband O2. The average factory O2 readings from those runs from 4000-6700 RPMs are 0.935V and 0.913V.

Tim

2001CamaroGuy

iTrader: (6)

what he said......WOT + O2s DOES NOT MEAN ANYTHING! If you want to tune WOT, take it to a dyno and then tune it there. Otherwise your asking to F-up your engine by being lean.

jimmyblue

iTrader: (11)

I think if you get the LTFTs right the WOT will
kinda take care of itself. Why the LTFTs are
positive, is the question.

First, you need to look at the trims by FTC
and see where the problem area might be. It
could be in the !EGR, which affects mixture
some. It could be the K&N having spooged up
your MAF wires. No mention of aftermarket
MAF, presume this is stock? At any rate if the
positive trims are confined to low MAP, low-mid
RPM cells (0,1,4,5) I would suspect the !EGR
may need you to go adjust the fuel target
related stuff there. I haven't had to learn about
that, with an '02. I think I'd definitely go get
some electrical cleaner like the CRC "QD" you
can get at Home Depot electrical section and
hose out the MAF just in case this is the K&N
oil-coking problem manifesting. And clean the
lid, neck & any hose too. If it is then you
would see large negative STFTs show up on
the logger afterward and the LTFTs come
back down eventually to zero or negative.
I would get a paper filter in there too. Just to
keep things stable once they're clean.

TimZ28

One other point...

Long Term Fuel trims do not indicate that the car is "currently" running lean or rich. They only tell you that based off of past O2 readings the PCM has has compensated for a prior lean/rich condition during closed loop mode.

Tim

BadManLS1

iTrader: (1)

I know its running a lil rich...I had it on a wide-ban o2 and AF was 12.5 ...I here that 12.8-13.1 is best for these cars. So the LTFT's should be on zero at WOT? I have the stock MAF and it is clean. My question is how do I lean it out a lil with hp tuners?

2001CamaroGuy

iTrader: (6)

hp tuners? as in HPP3?

slow

iTrader: (7)

NO hp tuners is new tuner, that is like edit in its capability.

well.. just impoved.. non vin locked, and includes a scanner as well

Ryan.

2001CamaroGuy

iTrader: (6)

really? can it do EVERYTHING that LS1Edit can?

slow

iTrader: (7)

as of now, nobody to my knowledge has posted anything that it won't do that edit will do.

they claim to have more tables than edit, but i haven't compared the 2, as i don't have an edit software package.

Ryan.

BadManLS1

iTrader: (1)

Anyone know how to adjust this in HP Tuners?

jimmyblue

iTrader: (11)

Well, if you wanted to an across-the-board lean-out
you would increase the value in the IFR (Injector Flow
Rate) table. However, since your LTFTs are positive
already, this will shortly be "learned", your LTFTs
will increase more, this will be laid onto your WOT
and right back where you started.

I think with an A4 you might want to scale >up<
the MAF table instead. This will increase the reported
load. The trans will shift later, firmer, should be all
good there (leaning out MAF table is bad though).
Timing advance will reduce, you may not like the
feel of this, but you can mess the timing table
around later (and on the stock tune there is plenty
to gain from doing so anyway).

Because your error is fairly large I would say to
scale the whole MAF table up x1.08 as a start
(unless, as I suggested, you have reviewed the
LTFT vs FTC map and know something about the
profile of error vs airflow that would let you apply
a more sophisticated scaling).

This will of course further enrich the WOT operation.
But it will make your closed loop close to right, and
I see no indication that the fuel system should be
represented as anything other than stock.

Now, given that the closed loop is barely below
0.0 LTFT in cells 8, 9, 12, 13 after all this, I
would say to start shaving on the PE vs RPM
and maybe later the open loop F/A vs MAP
tables until you bring the WOT fueling into line.

NOBR8KSS

iTrader: (12)

Positive LTFTs mean that the PCM is adding fuel ... compensating for a lean condition. If were you I would be adding fuel rather than leaning it out. This is for part throttle conditions.
Once you get the part throttle driving tuned, then move on to the WOT tuning.

TimZ28

In your scenario I would not touch the MAF table unless you have a modified MAF. Positive LTrims indicate the PCM is adding to the base pulsewidth in response to a previous lean condition. Drop the IFR table (ie. multiply by .94 - .95). This will tell the PCM that you have smaller than actual injectors. The PCM will bump the InjPW causing an initial rich condition. This rich condition will then be compensated for by decreasing the LTrims. You want to get the LTrims slightly less than 0 (-4 to -3 %) across most of the LTrim cells. This will then prevent positive LTrims at WOT. From there you can modify the PE table with confidence your A/F ratio will not fluctuate significantly from where you set as long as your LTrims are 0 or less. Modifying the MAF table when the MAF is stock is not the right approach in my opinion.

Tim
Tuner @ Macedo Motorsports (Orlando)

jimmyblue

iTrader: (11)

There's another possibility behind all this, which
is that the headers simply have the O2s too lazy
to work right and the low output is faking a lean
condition. This causes an improper enrichment.
If the LTFTs are most positive in the low-output
cells (FTC = 0,1,4) and the cruise / light accel
cells are good (5, 8, 9) then the "tune" might
better consist of some header wrap. If you watch
the O2 voltage graph at idle, let it sit idling
for a while, and see the "bounce" go from fast
jiggy to kind of slow and spending a lot of time
on the floor, this is something to think about.

NicD

iTrader: (7)

BadManLS1, This is what you should be doing.

TimZ28

The LTrims originally posted do not indicate to me there is anything abnormal. The addition of headers will change the volumetric efficiency of the motor and the positive LTrims are in fact the compensation for this change in VE. This is what you would expect to happen when you make an change that will increase the VE of the engine relative to an existing PCM calibration. If you wanted proof that everything is operating as it should put a Wideband O2 on the car and watch the A/F ratio during steady state closed loop operation (idle, cruising). If it fluxuates relatively close to 14.7:1 then the factory O2s are functioning correctly. If they weren't you would see a significant deviation from 14.7:1 on the wideband O2.

Tim

NicD

iTrader: (7)

Thankfully you are typing all this out. I am lazy right now and would have just ignored and not responded to the missinformation in this thread. You can only type it so many times....