slow throttle response when revving
Thread Starter
Advanced
Joined: Nov 2005
Posts: 74
Likes: 1
From: Toronto Ontario
slow throttle response when revving
Hey all,
the car seems to rev a tiny bit slow when giving steady gas. Also if just flip the throttle open from under the hood from idle it takes about 1/4 second for the the engine to rev up...i here a sucking noise which i assume is the TB sucking in air. I just finished big tune-up (plugs, wires, dist. cap/rotor fuel pump...etc. but i haven't taken off the TB to clean it or any of the sensors. Just wondering if i can quicken up that rev or it's normal for that little delay when tapping the gas from idle.
Thanks
the car seems to rev a tiny bit slow when giving steady gas. Also if just flip the throttle open from under the hood from idle it takes about 1/4 second for the the engine to rev up...i here a sucking noise which i assume is the TB sucking in air. I just finished big tune-up (plugs, wires, dist. cap/rotor fuel pump...etc. but i haven't taken off the TB to clean it or any of the sensors. Just wondering if i can quicken up that rev or it's normal for that little delay when tapping the gas from idle.
Thanks
Burning Brakes
Joined: Feb 2007
Posts: 786
Likes: 6
From: Manassas VA/Flagler Beach FL
St. Jude Donor '13,'19
Have you adjusted the TPS to .54 volts per the FSM. That is supposed to make it more responsive or so I'm told. Good Luck!
Last edited by glide; Mar 16, 2007 at 01:33 AM.
Pro
Joined: Nov 2006
Posts: 638
Likes: 0
From: Plano TX
I wouldn't think the TPS (throttle position sensor) would be out of adjustment unless you set your idle with the idle screw on the TB w/o following the right procedures.
If I were you, cleaning the TB always helps... I'd go for it. Pull it off, clean up the TB and IAC really well. Be care and make sure you use TB cleaner specficially. Also, don't go too crazy when cleaning your IAC. Once you're all done with that, reattach it and might as well go through the steps to verify your idle is set correctly. You'll be setting the TPS to specific volts correctly then.
FSM stands for factory service manual. It's a must have if you're going to be working on your vette.
If you check out the tech tips, it has a good write up on cleaning the TB and resetting your idle along with it.
Also, think about running some Sea Foam through your intake and fuel system.
There are many things that could be causing your issue... just keep it simple... fuel, air, spark. Troubleshoot those and you'll be on the right path.
If I were you, cleaning the TB always helps... I'd go for it. Pull it off, clean up the TB and IAC really well. Be care and make sure you use TB cleaner specficially. Also, don't go too crazy when cleaning your IAC. Once you're all done with that, reattach it and might as well go through the steps to verify your idle is set correctly. You'll be setting the TPS to specific volts correctly then.
FSM stands for factory service manual. It's a must have if you're going to be working on your vette.
If you check out the tech tips, it has a good write up on cleaning the TB and resetting your idle along with it.
Also, think about running some Sea Foam through your intake and fuel system.
There are many things that could be causing your issue... just keep it simple... fuel, air, spark. Troubleshoot those and you'll be on the right path.
Burning Brakes
Joined: Feb 2007
Posts: 786
Likes: 6
From: Manassas VA/Flagler Beach FL
St. Jude Donor '13,'19
I'm sorry I meant TPS (Throttle Position Sensor) and FSM (Factory Service Manual), both under minimum idle speed in Haynes. I'll edit my post.
Pro
Joined: Nov 2006
Posts: 638
Likes: 0
From: Plano TX
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
My 86 does the same. When blimping the throttle at idle, there is a slight hesitation. I have owned 2 other L98's but it has been some time and I can't remember if they were the same. I have clean the throttle body and IAC recently, TPS voltage is at .55v closed throttle and 4.52v at WOT, set the minimal idle, run a half can of Seafoam through the brake booster vac, and ran various engine scans. My LT1 revs instantly. Not sure if it is a problem or not, but it's not a big deal for me.
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Pro
Joined: Nov 2006
Posts: 638
Likes: 0
From: Plano TX
Another thought came to mind.... when you replaced your plugs and wires, did you make sure to plug it all in the right way? You don't happen to have a wire mixed up do you?
Also, I agree with RRT... I too have a slight hesitation, but nothing that makes me go too
Also, I agree with RRT... I too have a slight hesitation, but nothing that makes me go too
Instructor
Joined: Mar 2006
Posts: 111
Likes: 0
From: San Antonio Texas
1985 - If the plug is still covering the idle adjustment screw, is it necessary to adjust it along with the TPS? I just checked the TPS and mine was set at 71. I set it back to 54. I am not sure about messing with the idle. Good info here. 
Advanced
Joined: Jan 2007
Posts: 53
Likes: 0
From: Charleston SC
I too was having a slow/boggy rev for the first 5 or so minutes after startup.... I changed my temp. coolant valve... not the one to the gauge, the other one... little brass screw in part.
This stopped all of that. I don't know if this is the same type situation though.
Macfos
This stopped all of that. I don't know if this is the same type situation though.
Macfos
