jrnorman

According to my HP Tuner my max throttle position is 95 to 96%. This is with pushing the throttle flat to the floor.

I have verified visually that the throttle blade is not quite parrallel with the throtle body with the pedal floored but by pulling on the crank it can be opened to 100% by rotating it another degree or two.

Short of removing the carpet below the pedal to increase pedal travel, I can't find any adjustment by visual inspection or in the service manual.

Is the normal, does this small difference make any difference in performance, what can be done about it? Would this keep the PCM from performaning the WOT functions?

Thanks in advance, Bob

Camaro ChriSS

The PCM recognizes 95-96% TPS as WOT. Some diagnostic tools regularly only show a max of 96% open (Autotap used to do this - on some cars not showing 100%), but it is still WOT to the PCM.

Is this a throttle linkage car (f-body) or a vette? On the f-body, there is an adjusting point in a small black plastic cylinder that you can tighten the throttle cable with, if necessary. But you would want to be careful about going too far, and about tightening the cable so much that even at idle it is open 4% or so (which would make sitting at a stop light harder...).

txhorns281

iTrader: (12)

have you tried adjusting your throttle cable yet? Could just be a little bit of slack in the line, if you're saying that when you hit the pedal, and the blade does not hit the stop, I'd look there first, it's the easiest option.

jrnorman

Sorry, I meant to say this was a 2002 Z-28 and there is a flex cable connecting the throttle body to a black module over by the passenger wheelwell and two other flex cables going from the module to under the firewall on the driver side. I guess one of those is the accelerator cable and the other the cruise control(?).

I did not see any adjusting points but will look for some kind of cylinder in the cable connection.

Will not adjust more enough to affect idle but that was a darned good point!

Thanks, Bob

jimmyblue

iTrader: (11)

(1) Ruler, hand on the throttle body cable cam,
crack it full open, measure the position of the blade
edge across the face. Looking for dead center. If
not, "bump stop mod".

(2) Two adjusters, one from pulley cluster to TB and
one from cruise control to pulley cluster; release the
snap adjusters, pull hand-snug to where the TB is
barely -not- pulled off idle stop and re-snap.

(3) Pedal cable, pull full out by hand, check TB blade
position again (after bum-stopped if need be). Blade
should make it to center. If not you will need to make
a spacer for the TB cable to take up excess, non-
adjustable slack.

Any or all of these could be holding you back from full
open, and full open mechanical is what you are looking
for (electrical readings, swell, but it's maximizing the
airflow that you want).

I've seen one guy whose pulley cluster was the limit to
mechanical actuation, an internal bind of some sort.
He was going to get a '98-'99 TB or the shaft at least,
to get more opening for less pedal pull.

jrnorman

Thanks, jimmyblue!

I will print this out and see what I can do but I may need to email you for some clarifcations. I seem to find out that the clearest instructions are not too clear until you get it right then you want to slap yourself for not seeing the first time!

jrnorman

Thanks for all the helpk, especially jimmyblue. I thought those were just connectors not adjustments! It was easy and now I have a solid 0% off the pedal and exactly 100% all the way down (which is also the disc perpendicular to the throttle body throat).

I also tightened the cruise control a little to take out the 1 mph sag when setting it and that worked too!

Thanks again! Bob