‘93 Throttle not closing
Thread Starter
Advanced
Joined: Jan 2018
Posts: 88
Likes: 12
‘93 Throttle not closing
Driving earlier, my ‘93 LT1 decided to begin idling at 2500 RPM. Shut it down, an saw the throttle was staying a good distance away from the throttle stop screw. I was able to close the throttle by hand, restarted, and the idle was normal...UNTIL I pressed the accelerator, at which point the throttle again stuck away from the throttle stop.
Shut out the car back down, was able to note tension on the throttle cable. Moved the throttle closed by hand, and checked the throttle for free movement. All seemed normal moving the throttle by hand. While still shut down, pressed the accelerator, and once more, the throttle would not return to closed.
Bad accellerator cable, or is the ASC module/ASC cable involved in what I’m seeing?
Shut out the car back down, was able to note tension on the throttle cable. Moved the throttle closed by hand, and checked the throttle for free movement. All seemed normal moving the throttle by hand. While still shut down, pressed the accelerator, and once more, the throttle would not return to closed.
Bad accellerator cable, or is the ASC module/ASC cable involved in what I’m seeing?
Last edited by Galaxie500XL; Feb 21, 2019 at 09:17 PM.
Thread Starter
Advanced
Joined: Jan 2018
Posts: 88
Likes: 12
No codes...throttle body moves freely, and the ASR actuator hasn’t been adjusted in the year I’ve owned the car.
It appears the accelerator cable isn’t retracting all the way to allow the throttle to close completely, even with the engine shut off.
It appears the accelerator cable isn’t retracting all the way to allow the throttle to close completely, even with the engine shut off.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Floor mats or hush panel. Make sure pedal itself is free. There isn't a simple way to bypass actuator. If the cables are not binding i would be looking at actuator. If you turn off ASR does it change anything?
Thread Starter
Advanced
Joined: Jan 2018
Posts: 88
Likes: 12
Nothing seems to be in the way..turning ASR off doesn’t seem to affect anything...in fact, I can create the problem with the car completely shut down by pressing the gas pedal.
Le Mans Master
Joined: Feb 2005
Posts: 6,475
Likes: 565
From: Clearwater Florida
….. Spray lube it … I use silicone based spray lube … With the snorkel off , engine off , spray liberally at all points where the throttle shaft passes through the throttle body while working the throttle by hand … this should be on your once a year maintenance list like maybe on the day you remove the trash thats between the radiator and A/C condenser …..
Drifting
Joined: Aug 2009
Posts: 1,970
Likes: 242
I’d stay away from silicone spray, it will degrade oxygen sensors, spraying in or around the TB may find it’s way in. The bushings in the throttle body may be worn in which case it would need a rebuild or replacement.
ASR cable has an adjustment detailed in the FSM. Worth a check.
ASR cable has an adjustment detailed in the FSM. Worth a check.
Drifting
Joined: Aug 2009
Posts: 1,970
Likes: 242
Hopefully this link works, from the Society of Automotive Engineers...
https://www.sae.org/publications/tec...ontent/860478/
https://www.sae.org/publications/tec...ontent/860478/
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Thread Starter
Advanced
Joined: Jan 2018
Posts: 88
Likes: 12
We’re having a bit of a monsoon here, but went outside for a bit, pressed the accelerator, which popped the throttle partially open again. Found an adjustment button on the cable going to the throttle, pushed the button, and the throttle closed with a satisfying click. Drove around the neighborhood a bit, and the throttle appears to be operating properly.
I’ll get my FSM out, and read the proper method for adjustments, but at least for now, the car isn’t trying to do 30 in my driveway.
I’ll get my FSM out, and read the proper method for adjustments, but at least for now, the car isn’t trying to do 30 in my driveway.
Melting Slicks
Joined: May 2013
Posts: 2,692
Likes: 349
From: Sacramento California
The bushings on the throttle plate/throttle body mount are known to wear out, so check those. If they are not good, the throttle plate won't align correctly with the body and will hang up as you are describing.
Thread Starter
Advanced
Joined: Jan 2018
Posts: 88
Likes: 12
That’s very true. I have an ‘88 L98 IROC, and encountered that problem. The LT1 throttle body looks more or less identical.