Originally Posted by Grim Reaper

Before you buy a bunch of eproms or a UV Eraser, go with the AT29C256 Flash Prom. If you don't know what they are, do a little searching on them and you'll realize that this is the ONLY way to go with eprom burning if you can use them. And for SD cars, you can....and the easiest of ALL cars on this board.

Second, start with the 90-91 Corvette ANHT BIN. The Corvette BIN, while VERY CLOSE to an F-body BIN, also is different. The Corvette BIN has code to work with the oil temp sensor which the F-body version does not. Also, you don't mention your transmission but you should find a version for the ANHT with a 6-speed for the Corvette if you have a manual tranny. The best place to start is, again, your own Memcal.

Changes to make BEFORE even touching the VE Tables:

1) Set your Cylinder Volume in the constant table to 784cc. This will tell the ECM what size of motor you have to calculate the proper amount of fuel.

2) Set your Injector Flow constant to the "rated flow" of the injector. If you know the "correction factor" for the particular fuel pressure you are running (I recommend around 46-48 psi), use that. But don't get too hung up as whatever you put in here is going to be changed.

3) Set your "Desired Idles Speed Vs Coolant Table". This is assuming you have set your IAC and TPS. If you have not reset your IAC or TPS, go to the "Tech Articles" on this web site and read up on how to adjust the IAC, it is VERY SIMPLE but needs to be adjusted properly before you even begin to tune your eprom.

If your IAC/TPS are adjusted properly, then go into the "Desired Idle Speed vs Coolant Temp" to make the adjustment for the idle speed you want. With your LT-4 Cam, you probably want a higher idle than the stock BIN of 600-650 RPM. Probably more like 750ish at proper operating temp.

4) Now start taking your car for a "little drive" and drive at reasonably light throttle. An interesting observation that I have made is the lower VE Table for low-mid Load (kpa) and low-mid RPM is actually very similar for ALL SD engines, if the Cylinder Constant and Injector Constant are reasonably correct.

If at part throttle (1200-1600 rpm/40-60 Kpa) are all way below BLM 128, then increase the Injector Constant to lean the engine and raise the BLM value. Conversely, if the BLMs are all way above 128, then decrease the Injector Constant to richen the engine and lower the BLM value. Do this adjustment until you are notice that half of your BLMS are above 128 and half are below 128 (best scenario) or reasonably close to somewhere between 115-140. But the closer you can get most of the readings on the 1200-1600 rpm/40-60 kpa to 128ish, the better.

5) Now you are ready to begin tuning your VE table in ernst. In fact, you may find your car is even running reasonably well and fairly close...now you have a BIN close to what someone else would probably have e-mailed you or would have bought from a custom prom writer. Follow the "P730: Part throttle tuning VE (no PE)" and begin tweaking your VE tables. This will get your fuel mixture correct and once done, you will be ready to start tweaking the spark.

The above procedure is how I start ALL my bins.