BBK 75mm TB and IAB setting

I am setting the IAB on my 75mm TB and with the 520 lift cam I have to open it 3.5 turns for the power steering not to drop the idle more than 200 rpms. Anyone with a cam please add your IAB setting to this post. Dr Fred told me 1.5 turns and although my car idles with 1.5 turns it stumbles if I load the engine with the power steering. 3.5 turns keeps the idle steady when I load the engine using the power steering. Still using the stock MAF and transfer function.

Rich

Ford Shop Manual states:

5 Speed IAC Volts
Hot Idle..........30 mph..........55mph
8.7-10.3v.......7.8-9.2v.........6.9-7.9v

Auto IAC Volts
Hot Idle..........30 mph..........55mph
9.5-11.0v.......7.0-9.5v.........5.8-8.5v

I settled on 2 turns. The throttle stop was off too. I was adding idle rpm's when the EEC was set for stock idle rpm. I reset the idle screw to match the EEC Idle in Neutral and readjusted the TPS voltage to .95v. Then changed the neutral idle to 848rpm. Engine idle very good now.

Rich

Thats good to know.

Chris

I have long preached about correct TB settings and it still amazes me how many people with known idle issues still fail to follow this basic setup procedure.

Nonetheless, it has been in my experience that not all cars respond the same and not all TB's respond the same. Manufacturing tolerances on the aftermarket TB's are just not that good and the process simply HAS to be done. Particularly if you have a cam upgrade in the car.

I don't have any numbers to add to this list because I set the TB based on how the engine responds, not so much how many turns or what voltage etc. so I guess I'm not much help other than to say I totally endorse what Rich is saying here.

make sure you unhook the battery to reset the computer for 5 or 10 min , then it took mine about 3 days about 200 miles of driving before it learned to idle right again without stalling at stop signs , lately after doing fuel pump and headgaskets and fixing some vacuum leaks it doesnt seem to take as long , one time i just had tb anf maf off without unplugging the battery and it idled at 2000 for a week till i unhooked the battery then it was fine . i was blaming the throttle body for not being closed enough. i learned if you close the throttle body to tight without hitting the stop screw it sticks in the bore when you gas it and makes the throttle to touchy