BLK,97,T/A,M-6

I did a head, cam and Intake job on my car. I bought the tb used on here, and it is in very good shape. The problem is that the throttle will stick at low rpm's. If I blip the pedal, the r's will drop to where they should. This is the wierd thing, the throttle only sticks when the car is running. I cant for the life of me get it to stick when the engine is off. I removed the TPS and started the car, and it would still stick when running. I've cleaned the iac, and made sure the throttle cables were not bent hard. I'm lost... and out of ideas.

JAKEJR

Only time I personally experienced this on my car I just unhooked the return spring on the TB and turned it one full turn to increase the return pressure, the re-hooked it.

I once solved a friend's problem like yours by loosening all four TB bolts then cross-tightening them to a lesser torque, but still to spec. Over-torqueing tweaked the TB housing.

Only other things I can think of you already discounted: carbon build-up and/or butterflies closed too tightly, bent shaft.

Hope this helps.

Jake

West Point ROCKS!

crispytoast

iTrader: (17)

really grasping at straws but could it be that the itake is improperly ported for the larger throttle body butterflies? I know you said that it only does it when car is runining but maybe heat expansion on the butterflies is just enough to make it stick? Really grasping at straws here but just my .02

BLK,97,T/A,M-6

Like I said, I'm stumped.

Z20ATE

kinda had the same problem with my 58mm tb when i first put it on. when the engine was cool it wouldn't stick at all but as soon as it would heat up it stuck like crazy. what i did to fix this was actually sand the tb ports just enough to where it wouldn't stick anymore. haven't had a problem since

96capricemgr

iTrader: (1)

Blades are OVAL, if the closed stop screw is too far out then the blades will stop on the bores instead of at the stop, when running the engine vacuum will suck them in tighter towards true vertical.

I bet your stop screw just needs a tweak, check IAC counts and TPS voltage afterwards though.

BALLSS

I would check the later FIRST...then adjust stop screw if necessary.

if your IAC counts are to far out (VERY common with aftermarket TB's) the PCM is commanding TB blades to open more...which "may" be why they appear to "stick" when motor is on at operating temp.

you will need a scan tool to measure IAC. volt/ohm meter for TPS but scan tool can measure that as well.

96capricemgr

iTrader: (1)

You know how I constantly say you don't know a damned thing. Well you just proved it again.

Pcm can't command the throttle blades to do anything. No LTx cars were drive by wire.

If the blades are not overclosing I would look at tightening the throttle return spring but AS&M makes nice products and a I doubt they went marginal on that.

Puck

iTrader: (17)

My first guess would be slow or sticky IAC, second being the relationship of TPS and IAC voltage is out of range.

the_merv

iTrader: (88)

PCM has nothing to do with the Blades on a LT1 Car, just like mentioned above. The only thing that it directly controls in that area is the IAC.


To the OP..I suggest pulling it off and seeing if it's possibly scuffing on the Intake openings. That and clean it well.

BLK,97,T/A,M-6

This is the throttle physicaly sticking open, not the ecu not finding idle.