Question!!! Is this normal???
Thread Starter
Teching In
Joined: Jul 2009
Posts: 47
Likes: 0
Question!!! Is this normal??? 2001 Camaro SS A4(stock).
When crusing in 3rd or 4th gear going anywhere from 50mph - 70mph, when you floor it....should the car accelerate from the gear it's in, or downshift to the lowest gear the computer will allow it to based on speed and rpms??
My car has been not downshifting when i floor it anywhere above 50mph.....just wanted to ask if this is normal before I throw more parts at it...
Here is a list of the parts I have replaced in the process of addressing check engine lights and trying to figure out this downshifting problem :
Throttle Position Sensor - AC DELCO
Mass Air Flow Sensor - AC DELCO
Oxygen Sensor - Drivers Side(pre-cat) AFS-98 - AC DELCO
The car seems to run a little better after each part and now I have NO CHECK ENGINE LIGHTS.....but it still seems not 100%
PLEASE HELP!!!!!!
When crusing in 3rd or 4th gear going anywhere from 50mph - 70mph, when you floor it....should the car accelerate from the gear it's in, or downshift to the lowest gear the computer will allow it to based on speed and rpms??
My car has been not downshifting when i floor it anywhere above 50mph.....just wanted to ask if this is normal before I throw more parts at it...
Here is a list of the parts I have replaced in the process of addressing check engine lights and trying to figure out this downshifting problem :
Throttle Position Sensor - AC DELCO
Mass Air Flow Sensor - AC DELCO
Oxygen Sensor - Drivers Side(pre-cat) AFS-98 - AC DELCO
The car seems to run a little better after each part and now I have NO CHECK ENGINE LIGHTS.....but it still seems not 100%
PLEASE HELP!!!!!!
Thread Starter
Teching In
Joined: Jul 2009
Posts: 47
Likes: 0
thanks......any suggestions of what could be causing this??? The car hauls *** from a dead stop....feels like it's running normal....but it's just this downshifting problem.....at 40-45mph....it does downshift fine....but anything above 50 it doesn't
Try getting it to kick down with less than full pedal.
Like 75%. If it does it there but not at full open,
suspect a TPS overvoltage causing short-shifting
behavior.
Measure TPS voltage at WOT (engine off, key on)
and if it's over 4.7V you have to fix that.
"Bump stop mod" is commonly done and can be
overdone, causing this.
Like 75%. If it does it there but not at full open,
suspect a TPS overvoltage causing short-shifting
behavior.
Measure TPS voltage at WOT (engine off, key on)
and if it's over 4.7V you have to fix that.
"Bump stop mod" is commonly done and can be
overdone, causing this.
Thread Starter
Teching In
Joined: Jul 2009
Posts: 47
Likes: 0
Thanks Jimmy!
when i installed the TPS, i just bolted it on....was i supposed to make any adjustments??
how do i check the voltage?? I'm assuming I need to go buy a meter LOL....then what??
Thanks in advance for you time!!!!
when i installed the TPS, i just bolted it on....was i supposed to make any adjustments??
how do i check the voltage?? I'm assuming I need to go buy a meter LOL....then what??
Thanks in advance for you time!!!!
Tap a multimeter into the blue wire on the TPS, pull throttle all the way back (engine off, key on) and note the voltage seen on the multimeter. If your TB is stock your probably aren't getting anything close to 4.7 volts.
Trending Topics
Joined: Nov 2001
Posts: 34,628
Likes: 2,547
From: Schiller Park, ILL Member: #317
TPS voltage can also be verified via an OBD scanner.
With a 3.23 geared A4 (that's the stock gears for your SS) you should be downshifting to 2nd gear at up to 70mph.
If you can get your hands on a decent scanner, you can also verifiy what gear is commaned when you punch it at 60, 70, etc.
Are you sure the car has stock gears and/or stock tuning?
With a 3.23 geared A4 (that's the stock gears for your SS) you should be downshifting to 2nd gear at up to 70mph.
If you can get your hands on a decent scanner, you can also verifiy what gear is commaned when you punch it at 60, 70, etc.
Are you sure the car has stock gears and/or stock tuning?
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Thread Starter
Teching In
Joined: Jul 2009
Posts: 47
Likes: 0
thanks, i've since fixed my problem by adjusting my throttle cable.....
I'm not sure my gear is stock because I bought the car used....is there a way I can tell based on rpm/mph?
At 70mph I think the RPM's are right at 2k in overdrive(4th gear).
thanks
I'm not sure my gear is stock because I bought the car used....is there a way I can tell based on rpm/mph?
At 70mph I think the RPM's are right at 2k in overdrive(4th gear).
thanks
Joined: Nov 2001
Posts: 34,628
Likes: 2,547
From: Schiller Park, ILL Member: #317
This mod sure works, just tightened the cable and ground the bump stop off, the motor is very "flashy" now and lights the tires up in any gear...TPS was initially reading 3.9, now it is 4.65.
Joined: Nov 2001
Posts: 34,628
Likes: 2,547
From: Schiller Park, ILL Member: #317
The bump stop mod alone will never be worth major power. On the other hand, if your throttle cable is far out of adjustment, removing the slack can certainly be worth some power if you weren't even seeing WOT values with the pedal floored.
Is 3.9v even seen as WOT by the PCM? I thought it was 4.0v and above.
Thread Starter
Teching In
Joined: Jul 2009
Posts: 47
Likes: 0
yeah like on my car.....my throttle cable was out of adjustment for like 6 months....it was only getting 79.22% throttle and I was still beating mustangs all day.....lol
Now with it at 100.1%, it's like a whole new car....
Now with it at 100.1%, it's like a whole new car....
So, yes, getting 100% throttle finally DOES light up the tires in every gear...Like others said 3.9v was way to low to get kick down from 4th to 3rd, I was never really seeing full throttle. It's also much easier to get throttle from a stop/roll.
I found:
Throttle cable was too long (3.9v WOT from the pedal inside, tightened that up)
TPS read ~4.3 from the TB itself (ground the stop down until reaching 4.65v)
3.9v seems very low. Stock TPS voltage on all my LS1s has been 4.3v or 4.4v.
The bump stop mod alone will never be worth major power. On the other hand, if your throttle cable is far out of adjustment, removing the slack can certainly be worth some power if you weren't even seeing WOT values with the pedal floored.
Is 3.9v even seen as WOT by the PCM? I thought it was 4.0v and above.
The bump stop mod alone will never be worth major power. On the other hand, if your throttle cable is far out of adjustment, removing the slack can certainly be worth some power if you weren't even seeing WOT values with the pedal floored.
Is 3.9v even seen as WOT by the PCM? I thought it was 4.0v and above.
Not sure what the PCM value was, but I only saw 3.9v if I stood on the pedal from outside the car and PUSHED it into the carpet. Certainly a simple and valuable fix for me either way.
