I have scanned my 90 Vette after putting in a heated O2. The tune seems to need alot of work, so I am asking for some help as to how to intepret the scan and where to start tuning. The latest Datamaster scan is here. I appreciate any and all help you can give to me. I was using ANHT, but found the memcal cover today I had cut off and it said ANHU, is there any difference between them?
My BLMs are everywhere, my O2 is all over the palce as it was before with the O2 in the #7 header bung. It is now located at the junction of the Y pipe.

Setup:
GMPP ZZ4 crate motor (350ci)
113D heads 10.5:1 CR
LT4 Hotcam
1.6 rollers
Superram complete(upper and lower)
52mm TB
Hooker 2151 coated Long Tube Headers (1 5/8" primaries?)
no precats, gutted main cat
Flowmaster 50's
3.54 gears
700R4 Auto trans
All the basic performance mods, K&N etc.

Feel free to email me, should be in my profile, I appreciate it!

Thanks,
Doug

 

The first thing that strikes me as odd is how slow the O2 seems to be swaying from rich to lean and back... There are very few O2 crosscounts. Does anybody else think the O2 sensor might be too far downstream? It feels like it by looking at the short-term fueling and the O2 together. I'd start with a couple runs through VEMaster to get the fuel table closer, as you are pegged at 108 BLMs... You'll probably need to take a lot out of the VE tables at the low RPM/low-mid MAP range and add some in the higher RPM/upper MAP range... That'd be a good place to start...

 

I ran VE Master and it seemed to call for a correction factor of .9 +/- .05 pretty well across the board with a target BLM of 128. I scaled both the Upper and Lower VE tables by .9 to start. I will scan again next chance I get, Probably Thursday.
I forgot to mention, the O2 was acting all crazy like when it was only reading from the #7 header tube. There is a scan of before I put the heated O2 in here for reference if needed.

Thanks,
Doug

 

What type of number should I be looking for here? I just ran through the scan again and it reset twice (hit 255) so I figure that to be 739 crosscounts for the log run.

Thanks,
Doug

 

I scaled both VE tables by .9 and here is the newest data. Plaese take a look and let me know where to go next. I am thinking I still need to drop some fuel across the board again, maybe scale it by a factor of .95?

Thanks,
Doug

 

Looks like you're making progress... How is it running so far??

I'd try doing a log where you stay out of PE mode and get a good sampling of various load ranges and RPM ranges (drive around a hilly area, try also driving in 3rd gear some too (auto i presume))... Then run VEMaster on a copy of your latest bin (the one that you were using while making the log)... Then smooth out the bin that it modifies and see where that gets you.. It will probably save you a lot of time..

EDIT: just read that you've already used VEMaster once.. Try it a few times, you should start peeking out of those 108 BLM's soon...

 

Another thought, are you still running the stock injectors??

 

Negative on the stock injectors. I am running SVO 24lb injectors.

Thanks,
Doug

 

Wha is this and how do I stay out of it? Thanks on the progress, alot to keep straight. I figure I get the VE tables working right and then work out from there, one step at a time.

Tanks Again,
Doug

 

Never mind I found the information on the PE Tables. I was looking in the wrong place....



Thanks,
Doug

 

I assume you've changed the injector constant in the bin right??

 

Ok, I believe the 1990 corvettes were Speed Density right?

The first thing that I notice is that you are getting a Code 43 ESC. I would look into fixing that somehow.

Second note, I noticed that you changed the injectors. First thing you should do is change the injector constant before you try and determine anything from this data that you pulled. That should get your BLM's more in line. Then you can smooth out your tables with VEMaster.

 

HERE is the progress I made today. I changed the injector constant to 26 as I am using SVO 24# injectors per the info I researched on a conversion formula based on rail fuel pressure for ford wrt Chevy. I changed my approach a bit thanks to some advice and More reading I was able to do today in TRAXIONS guide..(THANKS TRAXION!!). The new data has stepped rpms to about 1600-1700 and I am working only on the lower VE tables right now. Still needs work though, I still have some rich spots and now I have induced some lean ones. I was beginning to work the cells in and was getting dark so I packed it up for tonight. I did do a cruizing log too for a loaded reference point as opposed to sitting in the driveway.

2 Questions....
1. Datamaster...Using the histogram, which is more important, the short term or long term?
2. When should I use the VE Smoothing tool? Between each PROM or after I get the tune where I like it?

Thanks to everyone!
Doug