Throttle Response slow
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
Throttle Response slow
I've heard everyone talk about how much better the throttle response is on the L98 over past carbed and crossfire models. I think mine is slower than older cars. Is there a way to increase throttle response or determine if something needs fixed?
Melting Slicks
Joined: May 2007
Posts: 2,382
Likes: 2
From: Kathleen FL
Your spark advance may be off. Check to see if the base timing is set at 6 degrees. Or for even more throttle response, set it to 8 or 10. You might have to start using premium gas if it pings.
Melting Slicks
Joined: Aug 2003
Posts: 3,393
Likes: 392
From: Lakeville MI
Check your timing first.
You can also experiment with spark advance to try and produce the most vacuum at idle. This should help.
Otherwise, you need to get into the tune's AE and perhaps the MAF filtering to speed up response.
I'd guess its going a little lean as you open the throttle.
You can also experiment with spark advance to try and produce the most vacuum at idle. This should help.
Otherwise, you need to get into the tune's AE and perhaps the MAF filtering to speed up response.
I'd guess its going a little lean as you open the throttle.
Instructor
Joined: Jul 2007
Posts: 236
Likes: 0
From: Mobile Alabama
Mine too
I just had cap, coil, plugs, plug wires and one injector & fuel pump & filter changed - rather costly hoping to get throttle response up but it's still same - car previously idled rough when warm and injector was root cause but plugs, cap, coil & wires were also partly problem. Mine runs great at full throttle but in part throttle starts just not much response. I
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
First check you timing. My 85 likes 10 degrees better than 6.
(trial and more trial and a few errors).
Next check the TPS. The TPS should be set to .54 volts when the key is turned on (car not running). Then have someone step on the gas peddle all the way to the floor..... now check reading....it should be 4.49 at WOT. If you have adjusted only to .54 you may be loosing the full WOT response. The TPS can be moved so you get both readings, just takes a little time.
I have my TPS adjusted to .60+, it seems to respond a little sooner. Past members have indicated that their cars like about .63.
And check your fuel pressure. When was the last time you changed the fuel filter? I have heard some information that the AC Delco filter has a larger diameter opening than other after market filters and flow better. I have not checked this aspect of the filter out yet. I change my filter about every 10,000. I have the FP set at 40 psi at idle and the FP hose off the regulator and plugged.
(trial and more trial and a few errors).Next check the TPS. The TPS should be set to .54 volts when the key is turned on (car not running). Then have someone step on the gas peddle all the way to the floor..... now check reading....it should be 4.49 at WOT. If you have adjusted only to .54 you may be loosing the full WOT response. The TPS can be moved so you get both readings, just takes a little time.
I have my TPS adjusted to .60+, it seems to respond a little sooner. Past members have indicated that their cars like about .63.
And check your fuel pressure. When was the last time you changed the fuel filter? I have heard some information that the AC Delco filter has a larger diameter opening than other after market filters and flow better. I have not checked this aspect of the filter out yet. I change my filter about every 10,000. I have the FP set at 40 psi at idle and the FP hose off the regulator and plugged.
Last edited by John A. Marker; Apr 25, 2008 at 08:42 PM.
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
My timing is at 6* and my TPS is at .54 volts and steadily increases up to like 4-4.5 volts at WOT. I havent tried adjusting it higher though.
My fuel is pretty much all new (injectors, pump, filter) and I had a Holley AFPR on it but it had no affect on the throttle response or anything for matter except making the car run rich, lol.
Is there a way to adjust the throttle cable or anything like that?
My fuel is pretty much all new (injectors, pump, filter) and I had a Holley AFPR on it but it had no affect on the throttle response or anything for matter except making the car run rich, lol.
Is there a way to adjust the throttle cable or anything like that?
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Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
Set you timing up to 9-10 and the TPS up to .6 and see how you like it.
They are easy things to do and return to original settings.
The throttle cable is a one time adjustment (there is no linkage adjustment). Here are the one time adjustments:
1. On the side of the throttle body you will find the TV cable. There is an adjustment locking tab that you press in.
2. While pressing the locking tab move the slider towards the back of the motor.
3. Release the locking tab and operate the throttle to full WOT and the slider will automatically adjust itself.
4. Drive the car.
-John
They are easy things to do and return to original settings.
The throttle cable is a one time adjustment (there is no linkage adjustment). Here are the one time adjustments:
1. On the side of the throttle body you will find the TV cable. There is an adjustment locking tab that you press in.
2. While pressing the locking tab move the slider towards the back of the motor.
3. Release the locking tab and operate the throttle to full WOT and the slider will automatically adjust itself.
4. Drive the car.
-John
Last edited by John A. Marker; Apr 26, 2008 at 01:12 AM.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
I have my TPS adjusted to .60+, it seems to respond a little sooner. Past members have indicated that their cars like about .63.
My method of adjustment is on my site. If you get it adjusted a tad too high at idle the ECM will toss a code and you can back off a bit.Once the TPS is optimized try advancing base timing into the 8-10deg range or until ping is detected.
Also, clean the TB & bore with TB cleaner.
Pro
Joined: Jan 2008
Posts: 584
Likes: 1
From: Near Lockport NY Black 1986 Coupe
The throttle cable is a one time adjustment (there is no linkage adjustment). Here are the one time adjustments:
1. On the side of the throttle body you will find the TV cable. There is an adjustment locking tab that you press in.
2. While pressing the locking tab move the slider towards the back of the motor.
3. Release the locking tab and operate the throttle to full WOT and the slider will automatically adjust itself.
4. Drive the car.
-John
1. On the side of the throttle body you will find the TV cable. There is an adjustment locking tab that you press in.
2. While pressing the locking tab move the slider towards the back of the motor.
3. Release the locking tab and operate the throttle to full WOT and the slider will automatically adjust itself.
4. Drive the car.
-John
Just goes to show what a little tinkering will do.
