borrowed a tb from a buddy for dyno day this saturday, its a bbk 58mm. well now that its on, my car falls on its face after 6k, i mean bad. throws a code, something about the throttle position (sorry i dont remember specifics, i THOUGHT that i had it fixed so i forgot what the code was) it has all of his sensors and stuff on it. any ideas as to what the problem might be?

 

A 58mm TB will be flowing into the 52MM Intake which will restrict the flow anyway, but as the Throttle positioner, someone else will have to answer that for ya.

 

Check the operation of the TPS with a scanner. Is your manifold bored out to 58mm to accomodate the larger TB?

 

I'd suggest using a multimeter to get the voltage on the TPS to make sure it is accurate. When I installed a 52mm on my T/A, I had problems as well... I had to drill/adjust the TPS for the correct voltage.

 

yea the intake is opened up for the 58mm

i checked it with freescan (similar to datamaster) and the throttle position would read something along the lines of "1," when it was acting up.

 

So the engine falls on its face above 6K RPMs? Doesn't your rev limiter engage at 6K, shutting off fuel to some of the injectors?

 

Your car is falling on it's face because it is not tuned for a 58mm and it throws timing and fuel off because it isn't reading accurate throttle position. When you are at half throttle with that TB, it is probably pulling as much air as the stocker did above 95%. This throws alot of stuff off. I run the same TB and it works great after the TPS is set up right and the car is tuned.

 

the rev limiter is set at 6800 there are a few mods that arent in my sig such as a futral cam and a few other goodies. the problem seems to have gone away i got on it several times earlier and it never did it, just spun the tires all the way through second