2000 4.3 (test and learn truck)

**joecar** · January 16th, 2012

The low end is under 2000 rpm.

Stoich is EQR 1.000.

Your B3618 looks ok (other than being overly rich where it exceeds 1.20; but that's ok until you have the VE and MAF table correct).

**blindawg** · January 16th, 2012

Alright, Thanks for the clarification.

After correcting the VE and MAF, what do you recommend for adjusting on the PE? Is there a rule of thumb for it?

Thanks again,
Branden

**joecar** · January 16th, 2012

When the VE and MAF are correct (BEN = 1.00 +/- 0.01 across the operating range; remember that BEN is the ratio of commanded fuel to wideband measured fuel), then PE can be set to 1.16 (corresponds to AFR 12.6 if fuel has stoich 14.63).

It's an empirical rule (people have measured on dyno and dragstrip) that AFR 12.6 (EQR 1.16) gets you the safest peak torque (i.e. is sufficiently rich to avoid knock, is sufficiently rich to produce peak cylinder pressure, is not overly rich to drown everything);

another empirical rule is to progressively lean out a little after peak torque heading to peak power and max rpm, reaching AFR 13.1 (EQR 1.12) at peak power (it has been found that slightly leaning a little like this makes more power at the higher rpm's past peak torque); but if you're going to do something like this you need to verify it with a wideband and dyno graphs or quarter mile time slips; and as always, be listening for knock and avoid it (knock is bad, it damages the motor);

[ "slightly leaning a little" : relatively speaking compared to peak torque; it obviously is not lean compared to stoich ]

[ notice I used AFR instead of EQR... when viewing/editing the tables, please do think in terms of EQR ]

for street use, it is simpler to set PE to 1.16 all across.

**blindawg** · January 16th, 2012

Thanks for that information Joe, I'll refer back to it when I get the MAF and VE figured out.

I'm fairly certain I'm doing this wrong, or started out with something that wasn't right to begin with.
I got a tune off of Tunedepot.com for a 2004 5.3 DBW. took the VATS off. Adjusted the fan settings. Then I went for a drive-
It jerked and backfired a couple times as it hit the higher RPMs (4800-5600) It would feel real doggy in the lower RPMs, and as RPM increased, it would feel more and more powerful until it started jerking and back firing. KR showed as 8 on the dashboard.

I then started looking into doing the AutoVE tutorial and noticed my IFR needed to be corrected. I copied and pasted the IFR table from an LS6 because I'm using an LS6 Intake/Injectors. And started doing the Calc.VET tutorial instead because Joe recommended it-

As I did the runs and adjusted the Tune the jerking and backfiring got worse. After adjusting the PE as Joe recommended it feels like its hitting the rev-limmiter, but as soon as I let off it feels powerful as I let up on the pedal, but doggs back down when I push back down. I assume I am doing something wrong, but I'm getting frustrated at it at this point.

Tune I started out with:Branden stock 5.3 no VATS_E_fans.tun
Tune With adjustments from last log, I have not yet flashed this one:Branden CalcVET_0009.tun

Thanks Guys, Help is much appreciated,
Branden

**joecar** · January 17th, 2012

Hi Branden,

I'm looking at your files, the VE and MAF tables are not progressing correctly...

can you post the log file that produced the CalcVET_0009.tun file.

**joecar** · January 17th, 2012

Also, try this: set B0120 to zero, and take another log using a .tun file where the VE and MAF tables are smooth.

B0120 works like this:
above this rpm, the PCM uses the MAF exclusively for airmass and ignores the VE;
below this rpm, the PCM uses the MAF for steady state conditions, and the VE for transient conditions.

I'm still looking thru your tun file, it will take me a while I have various things all going at once

It can be frustrating at times, but don't be discouraged, there are logical reasons for what is going on.

**blindawg** · January 17th, 2012

Originally Posted by joecar

I'm still looking thru your tun file, it will take me a while I have various things all going at once

It can be frustrating at times, but don't be discouraged, there are logical reasons for what is going on.

No worries on the time, we all have lives.

I'm not discouraged, just frustrated for the time being.

I'll post the log when I get home, along with adjusting B0120 and I'll post up results.

Thanks Joe,
Branden

**blindawg** · January 17th, 2012

Log Used to make Calc.VET_0009: CalcVET_0008.efi

Branden

**joecar** · January 17th, 2012

Which engine do you have...?

The calc'd VE table is calculating high...
this has to do with your engine being a V6 and the VE calulation being for a V8...
I'm sorry about this mix up, I should have realized earlier;

this means you have to do one (and only one) of the following:
- change all your VE units to % [ ugh, I don't like this ];
- edit CALC.VEN to change CLC-00-300 to this (see the red part) [ I like this ]:

Code:

*CLC-00-300
%            0.0      100.0     .2  "{SAE.MAF.gps}*{CALC.DAT.K}/{SAE.RPM}/{SAE.MAP.kPa}*3445.2/displacement()"
VE           0.0        2.468   .4  "{SAE.MAF.gps}*{CALC.DAT.K}/{SAE.RPM}/{SAE.MAP.kPa}*20"

The attached calc_pids.txt file contains this change.

I noticed the dynamic air temperature is not correct (it should be somewhere between IAT and ECT, and should never be below IAT); if this persists, then you may have to create a lookup calc pid from table B4901 (the Calc VET thread shows how; I can help you with it).

I edited a few things in the stock file you posted in post #164 above, see attached, you can go to the History tab and scroll to the bottom to see what I edited (you can also open the original file as the alternate calibration and use the compare feature to see the differences in the new file).

WARNING: the attached calc_pids.txt is for doing Calc.VET on a V6 engine.