Steve Bryant

iTrader: (1)

This is off topic somewhat, but from the nature of the questions, I didn't feel that a basic overview of SD tuning would hurt. This isn't enough information to really tune the engine, but it does hit some of the high points.

Here are my basic recommendations without getting into all the details (which I can't remember right now anyway):
1. Set your injector flow rate for their correct rating at 58 PSI
2. Set your cylinder volume for the displacement
3. Disable Closed Loop, MAF and DFCO
4. Retard high and low octane tables about 5 degrees on the whole table (vehicle will run like a dog, but it will keep you out of knock retard until you get the mixture set-up).
5. Work with the Volumetric Efficiency (VE) Table to get Stoichiometric mixture (about 14.7 AFR) everywhere. It doesn't have to be perfect but shoot for 14.5 to 14.9 in all cells to get things in the ball park. This is so called Speed Density Tuning (you are only adjusting the VE for Stoic at various RPM's and manifold absolute pressures (MAF) and taking MAF, PE, DFCO and timing out of the picture so you can focus on basic mixture calibration.

Also, here is a post that I did in 2005 on some of the basics for tuning https://ls1tech.com/forums/showpost....07&postcount=4. It's a short thread and you might want to read the whole thing (click on the thread title in the upper right hand corner of that post).


Steve

Quik

iTrader: (7)

use thsi file to get you running. thsi will get you idling. i idle around 800

now this is a base SD tune and should work for you

again this is a base tune that hasnt been worked but my truck does idle right off the bat. i also have SVO injectors

my setup is 244/248 612/615 112+2, L92s/L76, 90mmtb, 11.1 SCR on a 408

adam1803

iTrader: (65)

Thanks guys, i appreciate the help so far. I gotta work tomorrow so i don't know if i'll get a chance to mess with it but i'll let you know how it goes.

adam1803

iTrader: (65)

Well i tried out that tune today Quik, it was easier to keep it running with a little gas, but it still wouldn't idle at all.

Im going to stop starting it now until i get it to the point that i can drive it so i can do a good break-in on the motor.

Im seriously thinking about going with a SD tune though. Thanks for the help.

Quik

iTrader: (7)

that tune i gave you is SD. you need to remove the maf for it to work

also you might need to drill your TB along with play with the throttle screw to dial in your TPS signal along with your IAC counts

Steve Bryant

iTrader: (1)

Adam,
As Richard recommended, I'd be very reluctant to drill any more holes in the throttle blade. You can crack the throttle open a bit with the adjusting screw and achieve the same thing until you get the idle air control set up better. I think that you're using good judgment to not run the engine any more until you get the transmission/driveshaft/etc. installed and you can actually place a load on the engine to get started seating the rings. For now, just take a few steps back from your project and be pleased that the engine runs and you've got your oil pressure issue solved. Maybe even take a few days off and start back next weekend and you'll have more perspective about everything. I'm assuming that you have another vehicle to drive since you went to work today.

Best of luck,

Steve

blown3qtr

Got my 408 running last night. I was having a similar problem w/ my tune. I used quik's tune as a guide. Truck idles now. Still got quite a bit of tuning to do.

Thanks Quik!