Yardpro

Can I start and run my ls3 on a stand without the accelerator pedal hooked up?

RB04Av

Yes, if it's DBC. Much tougher if DBW.

Yardpro

its DBW. i guess my question is can i manipulate the throttle body by hand. From the looks of the wiring, etc, the pedal is just a potentiometer and not needed for the computer to adjust fuel etc if the throttle body is opened by hand

RB04Av

Well you can try it I guess. Poke at the blade with your finger. Not sure how you're going to do that and still have the MAF connected, but w/e. You'll figure it out, no doubt. Whaddya got to lose, right? (besides a little sanity)

Yardpro

iit shouldnt require the maf to run, or at least that is my understanding.
i am just wanting to do a quick start to make sure i build oil pressure etc.

TrendSetter

you dont say what ecu youre using
dbw throttle bodies when unpowered are usually in the 30% range but at idle they tend to be in the 14-16% range so if the throttle body is unpowered its going to rev up kinda high. they are designed this way as a failsafe so you can still sorta move the car around if it dies.
if you can put a dbc tb on it that would probably be better.

Old Buzzard

And then there's no way to get a tps signal.....

Yardpro

I’m using a link extreme ecu

Yardpro

The. Computer should still read the tps as they are separate inputs /outputs from the steppermotor. I don’t think the stepper motor (which is what the throttle pedal controls) has any connection to the tps other than just turning the heat that moves it.
Is that not correct?

Old Buzzard

OP; without the accelerator pedal hooked up?

Yardpro

Am I incorrect that the accelerator pedal only moves the stepper motor. I don’t think it has any electrical connections to the tps.

RB04Av

The accelerator pedal communicates with the TAC module, which then opens the throttle according to the driver's input.

Your odds are better if you have an actual pedal module (a 3-section potentiometer) and a TAC module, with all the wiring of course. By NO MEANS impossible; just, not trivial.

IMO after building dozens, maybe over a hundred, engines over the years, starting them up before installation has always turned out to be a mistake. More trouble than it was worth, at best; a path to some disastrous screw-up, more often. (like one time my compadre forgot to put on the oil filter ) I got to the point that I became as rigorous and certain of the outcome as possible, and just learned to install motors in cars, put in the fluids, hook up every tube and wire and hose, COMPLETLY finish the COMPLETE install COMPLETELY including every bolt clip clamp connector air filter WHATEVER, CLOSE THE HOOD, reach in the window, and start it up. All of the "I just wanna hear it run", "make sure it has oil pressure", "what if I [fill in the blank screw-up]", ALL OF IT, was as useless as **** on a chicken. DO IT RIGHT and there's nothing to worry about. After all, the factory doesn't put themselves through that either, yet they manage to turn out MILLIONS of units a year.