Years ago, I rebuilt two small blocks, put a cam in another, rebuilt carbuerators, etc. so I'm not completely clueless. But, I don't know beans about an OBDII controlled engine. I have the Helm's Manuals and I'm willing to spring for a laptop and AutoTap, but what does a dummy do with them??? So AutoTap shows too rich, too lean, knock retard, etc, but then what can be done to correct the situation? It's not like turning a mixture screw on a carbuerator. I've looked for a book on the subject but can't find any. Any advice is greatly appreciated.

 

Transitioning from a carbed background to EFI was somewhat intimidating for me when I did so, so I understand where you are coming from.

There are several things we can do to "fool" the PCM and gain power with these cars. The only other option is to have the computer custom programmed or dyno-tuned. But, instead of that stuff, we can do such things as:

-Porting the MAF body. This fools the motor into thinking it is under less load because the velocity of the air over the sampling wires slows down. This "perceived" load reduction results in the PCM giving us more ignition timing and leans out the air/fuel mixture a bit. Both gain power unless you go too lean.

-MAF Translator. This device has two adjustable ***** that tweak the MAF readings and fool the PCM. You can adjust them to get good O2 sensor readings and better timing numbers. You can also adjust your LTrims (these determine how much our PCM is adding/removing fuel).

-Custom PCM tuning or Hypertech Programmer. Hypertech Non-RFG tuning usually gives us about 3 degrees timing. You can get whatever timing you want with custom tuning.

-LS1 EDIT. This software will let you tweak all kinds of stuff. Timing values, air/fuel ratios for each rpm, turn off certain SES codes, delete some emissions stuff, etc...

With the Autotap, I generally monitor:

Engine Coolant Temp: want less than 190F
Engine rpm
Throttle position %: only WOT data is useful
B1S1 O2 sensor: This is the first O2 sensor on the driver's side. Look for readings between .890-.900 for best power results
B2S1 O2 sensor: same as above, but passenger side
Ignition Timing: 28+ degrees is ideal
Knock Retard: 0 knock retard is ideal
Ltrims B1: close to 0 as possible
Ltrims B2: close to 0 as possible

Hope this helps!
Tony

 

Thanks for the help, Tony. Makes me feel better about getting started.

 

Excellent info for "new tuners".

Good job Tony.

Hey all you new to the scene racers!
Read what tony has typed and UNDERSTAND it. Once you have done that... you will be a much better tuner and not just a wrench turner.

A tuned modified car will DESTROY a simple bolt-on or modified car. Tune it to get everylast HP out of your combo... you just might suprise your self.

Again.. EXCELLENT info there Tony. I hope somebody reads it. <img src="gr_stretch.gif" border="0">

 

http://www.vetteguru.com/mods/howto/

 

Thanks for the insight!! I've messed with carburated engines forever..now i've switched over to fuel injection for everything and feel like an idiot sometimes. I have Job Spetter Jr. coming down to Kentucky when my Malibu gets done next month just to setup the DFI since I dont know a thing about it...so it will be fun to watch him and learn some things.
Thanks for the information here! Great way to get started with my firehawk. (added tnt kit over Christmas..havent hit it yet 'cause I wasnt sure what I should look for in the tuning.. you just clarified it for me!)

 

Glad I could help anyone that reads this. This knowledge didn't come easy, its the results of working/tweaking on these cars for over 3 years now. We Houston guys are notorious "tweakers", right John? Patrick? Larry? Brooke? <img src="gr_grin.gif" border="0">

Tony

 

I`m in the same boat, coming from dealing with carbed engines up to this point, the FI scene is new to me also. Although, I`ve already learned alot just but monitering this site. The Admin`s here do a awsome job and all you have to do is check out there ET`s to know they know there stuff. So a big pat on the back to the people who keep this site running. With there help and a little reading/learnig/experimentation, I`ll be Autotapping,scanmastering and LS1Editing by spring!!! Thanks guys. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />