BBK TB, Need to repositioin the TPS?
Thread Starter
Registered User
Joined: Apr 2000
Posts: 148
From: Woodlawn VA
BBK TB, Need to repositioin the TPS?
the throttle postion sensor doesn't line up right on my 58mm TB. I have to turn it to get it to fit, and that will make the computer read wrong when i fire this thing up. Anyone with a BBK have this problem? what did you do just drill two new holes for it in the throttle body and tap em?
Administrator
Joined: Nov 1998
Posts: 71,098
From: Hell was full so they sent me to NJ
Do you mean you slipped the TPS over the end of the throttle blade shaft, and have to rotate it slightly against the spring to get the screw holes to line up? If so, that may not be a problem. After you get the TB installed, I would first check the IAC counts, and then verify the TPS voltage at closed throttle.
Sometimes they ship the TB's with the throttle stop screw out a little too far. That will usually push the idle too high, and the IAC counts will bottom out before the idle speed comes down where it belongs. Having the stop screw out too far would also cause you to have to rotate the TPS sensor a little farther to make it line up with the holes.
Watch the idle speed. Back off on the throttle stop screw slowly until the RPM is on spec, then verify that the IAC is in the 20-40 counts range. Then check the TPS voltage. Anything between 0.20-0.90V will satisfy the PCM, but some people like to try for a value in the 0.60-0.67V range. In order to achieve that, you might have to slot the screw holes in the TPS sensor to allow it to be adjusted.
Sometimes they ship the TB's with the throttle stop screw out a little too far. That will usually push the idle too high, and the IAC counts will bottom out before the idle speed comes down where it belongs. Having the stop screw out too far would also cause you to have to rotate the TPS sensor a little farther to make it line up with the holes.
Watch the idle speed. Back off on the throttle stop screw slowly until the RPM is on spec, then verify that the IAC is in the 20-40 counts range. Then check the TPS voltage. Anything between 0.20-0.90V will satisfy the PCM, but some people like to try for a value in the 0.60-0.67V range. In order to achieve that, you might have to slot the screw holes in the TPS sensor to allow it to be adjusted.
Registered User
Joined: Mar 2003
Posts: 1,411
From: Pelzer, SC
About the idle about a bigger TB install...I had to get mine tuned down, cause when I would crank it, it would rev up like crazy. And when I put it in reverse, I wouldn't even have the pedal pushed down and it would back up really fast. At stop lights and stop signs, it would start trying to jump even with the brake pushed all the way down.
Thread Starter
Registered User
Joined: Apr 2000
Posts: 148
From: Woodlawn VA
i'll check the throttle stop screw, but the blades seem to be fully closed. I had to rotate the tps sensor more than slightly to get it to line up.
I don't have any kind of volt checker on hand, but thank you for the advise, well appreciated to all.
I don't have any kind of volt checker on hand, but thank you for the advise, well appreciated to all.
Thread
Thread Starter
Forum
Replies
Last Post
tdigger9899
General 1967-2002 F-Body Tech
9
Sep 7, 2015 10:56 AM