Newbie FAST help... (twin turbo LT1)


lurking chevy guy
Hey everyone, I finally got my project nearly complete.

I connected to the FAST, and got my injector constant and a few other simple things corrected, and started the car. Much to my suprise, the car fired right up!:D Hell, it sounded pretty crisp, but it was surging.. It eventually died, but it restarts easily. I was preoccupied with making sure I didn't have fuel/oil leaks or something detrimental.. Anyway, I ran out of time and had to leave town for a week (this week), and I'd like to learn all I can about the system so when I get home next weekend I can get the car out on the road.. sooo..

Is there a good FAQ anywhere, or definitions of the tables? I'm familiar with the theory, I used to use the LT1_Edit software for the factory PCM.

Is there an online troubleshooting guide so I can get this thing running with minimal trial and error?

Does anyone have a forced induction file I could see for somewhat of a reference? I have my .lt1 files, but they all max out at 1 bar, (100kpa)... I'm using a 3-bar MAP sensor, and I'm curious about the linearity of curves vs. MAP..

As always, any help would be much appreciated! :)

'96 twin turbo Z28 home page
If you have the Windows software, the help files are built-in and describe all the tables used for tuning. These help files are also on the website in my sig file.

There is a "demo" calibration file on your C-Com disk as well. Came from a turbo Buick. You can browse through that and maybe get a feel for what you are going to do.
brady, email me at and i'll send you one of my files... i'm running a 396 LT1 w/a t-trim... i've got a 2-bar map sensor... but you might be able to use it as a reference...
Thanks Craig and Jeff. I've got the car idling pretty good now, it's pretty responsive too. It dies when I let off the gas, but I can work on that later.

I have a question about the TPS. The FAST says my throttle position is 16% when the throttle blades are closed. At WOT the FAST says I'm at 91%. I'm using a piggyback harness and my factory PCM says I'm at 0% when the blades are closed and 100% at WOT. The TPS voltage is .80 with the blades closed FWIW.
Does anyone have a cure for the discrepancy?

Thanks! and I welcome all the help I can get!
It's not a problem actually. The only things the TPS is used for is to tell the ECU where the car is idling and to apply acceleration enrichment fuel. There's no need to make it go from 0 to 100.
Brady, mine is running pretty good if you would like to try it out. Just e-mail me. (95blowntaconvt from
Thanks guys.. Jeff, your file helped tremendously.

I've been driving it on the street this weekend, it's wicked on the street:eek:

I'm getting there....

Tom, if you get a minute, send me your file:
Thats a nice car and site that you have. But are those dyno numbers with or without the turbos. The numbers seem really low.
Originally posted by GNVAIR
Thats a nice car and site that you have. But are those dyno numbers with or without the turbos. The numbers seem really low.

LOL.. Those dyno numbers are from '99... I'll get back on the dyno again soon...
Hey Brady glad to see your car is coming together!

When i first tuned my car, I started with the Buick program and brought it over (when I had the vortech last year) and will do the same thing this year when I tune the T88 in. ;)

Good luck!