Auto VE Question

[bsteff]

I have a relatively stock Silverado SS (CAI, Cat Back). After doing AutoVE with a 10% increased VE should I have any BEN's above 1?

I did this today and got 1.10 BEN's in the higher MAP ranges. I then added 10% to those cells and got about the same BEN's on the next log.

Any ideas? I followed the tutorial exactly and I am getting P0103, so I am pretty sure I am in SD. Wideband appears to be working correctly.

[Chevy366]

I have a relatively stock Silverado SS (CAI, Cat Back). After doing AutoVE with a 10% increased VE should I have any BEN's above 1?

I did this today and got 1.10 BEN's in the higher MAP ranges. I then added 10% to those cells and got about the same BEN's on the next log.

Any ideas? I followed the tutorial exactly and I am getting P0103, so I am pretty sure I am in SD. Wideband appears to be working correctly.

I am no expert by no means , but you only add 10% or 15% to the VE once and log the Wideband data as shown and as someone said "wash , rinse and repeat ." .
I did mine 3 times and hit lots of cells or as many as I could , I did 1st gear cells then 2nd gear cells so on and so forth .
My BENs were at 0.98 to 1.01 on the ones hit through the ranges of course you are not going to hit every cell in the VE table so hand smooth or use the Interpolation Spread Sheet to smooth the VE table .
I posted a picture of mine before and after AutoVE , do a search and you will see what I mean by not every cell is hit . http://forum.efilive.com/showthread.php?t=4369&highlight=AutoVE

[bsteff]

I started the AutoVE process and saw BEN's around 1.10 and was concerned about running lean (see top pic). So I went back and added another 10% to the VE in the high MAP range trying to stay on the safe (rich) side and after repeating still saw cells in the same range in the 1.10 range (see bottom pic). When I saw this I stopped and reflashed the stock tune and decided to ask before continuing.

The point of starting with a 10-15% increace in VE is so that you tune your fueling from the rich side right? I am pretty sure I have some type of problem. Maybe something mechanical like a vacuum leak? Or is there something I could be missing in the calibration that could cause this?

Any input is appreciated

http://img.photobucket.com/albums/v715/bsteff/log1.jpg

http://img.photobucket.com/albums/v715/bsteff/log2.jpg

[Garry]

Make sure you actually have the Tune tool set to EQ, not Lambda! Otherwise you are going in the wrong direction, with EQ = 1/Lambda ... I somehow ended up doing this on the first couple AutoVE runs, wondering why there were Knock Retards showing up ... :bash:

[joecar]

Bsteff,

Check that your MAP units in the scan tool match the VE table's MAP units in the tune tool... are you using inHg in both places...?

kPa may be easier to work with since this ranges 0-100 for non-boosted.

And as Garry said, check that the tune tool is not set to Lambda.

And do check for air leaks in the exhaust (upstream of where your wideband sensor is measuring, and maybe 8 inches downstream).

Cheers
Joe

[bsteff]

Units match on my Map and VE table and commanded fuel values are displayed as EQ ratio. I will look for leaks today. Does the fact that this only happens in higher MAP areas mean anything to you guys. It seems to me like the truck wants to run 14.6 AFR even when B3605 tells it to run 13.

[dfe1]

Are you sure short and long term fuel trims are disabled?

If you're having trouble finding the problem, try reverting to full closed loop operation and see how the system reacts. If the long term trims show the same type of correction values, it's a good bet that the problem is mechanical. Also, if you logged manifold pressure before you started, check your old logs. If manifold pressure is substantially different than it is in current logs, you probably have a vacuum leak.

[Chevy366]

Units match on my Map and VE table and commanded fuel values are displayed as EQ ratio. I will look for leaks today. Does the fact that this only happens in higher MAP areas mean anything to you guys. It seems to me like the truck wants to run 14.6 AFR even when B3605 tells it to run 13.

Post your tune and log files .

[bsteff]

Here is my auto ve tune file and a log file. I didn't find any exhaust leaks.

[Chevy366]

De-screened MAF ?

[bsteff]

De-screened MAF ?

No. K&N cold air intake.

[bsteff]

Are you sure short and long term fuel trims are disabled?

If you're having trouble finding the problem, try reverting to full closed loop operation and see how the system reacts. If the long term trims show the same type of correction values, it's a good bet that the problem is mechanical. Also, if you logged manifold pressure before you started, check your old logs. If manifold pressure is substantially different than it is in current logs, you probably have a vacuum leak.


When I go back to closed loop SD I get -LTFT's and BEN's <1. This is what I would expect with the VE table scaled up from stock. Can anyone find a problem with the way I set up the AutoVE tune?

[bsteff]

Problem Solved!

After some searching in the tune file I found parameter B4206 "Use O2 With Open Loop Commanded Fuel Table". This parameter was enabled on my stock tune. I disabled it and went out for a drive. BEN's in the 0.95 range, right where I expected them to be.

Maybe disabling B4206 should be added to the auto ve tutorial for people like me who have that parameter enabled on their stock tunes.

P.S. Thank you to those who repiled to this thread.

[Chevy366]

Great , I took a look (like I know anything) at the tune file did not see anything unusual , I did notice that the BEN for the LC-1 across the top you have the values in Metric , I did mine in Imperial which the values are 15-105 MAP , but I have Imperial values through out the Tuning software .