2001slppewterss

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!!!!!!

blade2222

no it's not. mine will drop a gear at 70.

2001slppewterss

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

jimmyblue

iTrader: (11)

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.

2001slppewterss

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!!!!

2001slppewterss

ttt ...........

$750 L98

iTrader: (7)

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.

RPM WS6

iTrader: (3)

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?

2001slppewterss

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

RPM WS6

iTrader: (3)

Sounds like a stock 3.23 in that case, assuming you've still got 25.66" tall tires (275/40/17).

99FormulaM6

iTrader: (21)

70 mph and around 2k is 3.23s. with stock gearing, you are at 2100 rpm at 71mph

2001slppewterss

yeah....still got the stock tires.....

$750 L98

iTrader: (7)

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.

ae13291

iTrader: (8)

your trying to say a bump stop mod now lights your tires up in every gear?

RPM WS6

iTrader: (3)

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.

2001slppewterss

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....

vtirocz

What method did you use to ensure the throttle cable was adjusted correctly? Measure voltage at TPS with someone holding the pedal at WOT from inside the car?

99FormulaM6

iTrader: (21)

you dont have to have someone inside the car pushing the gas pedal, you can just move the throttle by hand on the TB

$750 L98

iTrader: (7)

I have a swapped LQ9, headers, LS6 intake, true duals, XER281HR cam, 3.73 rear, Yank 2800, built 4L60E, etc.

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)

$750 L98

iTrader: (7)

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.