tps loses referance
Thread Starter
Teching In
Joined: Aug 2009
Posts: 8
Likes: 0
tps loses referance can any one explain how the pcm maintains its referance for tps angle.i just got my 02 escalade engine in my 64 nova trans was shifting funny.i have a 00 f body pcm and cable throttle body off i dont know.ls1 intake. i found that at wot the tps is showing 25 % angle i tried a new tps got the same results.so i keyed on with tech 2 and cut tps tabs off and adjusted it till i saw 100% angle wot. rd tested car oh boy it was fun. thought i had the problem resolved.next day i went for a ride and it was back to its old ways.i reinstalled t 2 hit the gas wot and the angle is at 70% .tps did not move.any ideas on how i can fix this thanks kenny /i posted a similar thread in basic questions but got no replies
The PCM tries to learn what voltage makes what %.
Be sure your idle voltage reads 0.5 - 0.7 and your
WOT is below 4.7V but not by much.
If you have to jack the angle to get WOT right you
are having to steal from idle. Set up the TB so it
gets to dead open by ruler across the throat opening,
and then true up the TPS. Don't mess things around
based on electrical readings until you know the
mechanicals are all proper.
Be sure your idle voltage reads 0.5 - 0.7 and your
WOT is below 4.7V but not by much.
If you have to jack the angle to get WOT right you
are having to steal from idle. Set up the TB so it
gets to dead open by ruler across the throat opening,
and then true up the TPS. Don't mess things around
based on electrical readings until you know the
mechanicals are all proper.
Thread Starter
Teching In
Joined: Aug 2009
Posts: 8
Likes: 0
thanks jimmy i will play with the mechanical part of the t/b .not quite sure what you mean are you saying to ck the butterfly position in the body bore .could i adj that by bending the tab on the cable fixture.there is an adjustment screw on the body ,it is almost flush with body.seems if i adj it the veh will idle at a higher rpm .if poss please be more specific on what you are asking me to do.thanks again for your help.
At idle you want the butterfly to barely-not-bind
in the throat. I'd back the screw out until it does
bind and then turn it in until you just feel the blade
start to move. Just as much, as doesn't stick under
vacuum. No more.
At WOT, you want the blade to be dead center at
the edge. This involves the bump stop and you may
end up filing that. Too far over center and you can
end up with TPS overvoltage, but you don't want
to use a voltage reading to tell you what's
geometrically straight-up.
Now you also need to be sure that the pedal has the
ability to draw it full open. That's snap-adjusters,
pedal arm angle (bend it more, in a vise, if need
be), maybe the TCS gizmo binding it up. Wedge the
pedal to the mat and recheck the blade travel.
So now you've got both ends of the range mechanically
ideal, leaving any sensor troubles to be relating to
just that. A stock TB and TPS, if set up clean, should
be able to give you 0.6V at idle and 4.6V at WOT, all
nice-nice.
in the throat. I'd back the screw out until it does
bind and then turn it in until you just feel the blade
start to move. Just as much, as doesn't stick under
vacuum. No more.
At WOT, you want the blade to be dead center at
the edge. This involves the bump stop and you may
end up filing that. Too far over center and you can
end up with TPS overvoltage, but you don't want
to use a voltage reading to tell you what's
geometrically straight-up.
Now you also need to be sure that the pedal has the
ability to draw it full open. That's snap-adjusters,
pedal arm angle (bend it more, in a vise, if need
be), maybe the TCS gizmo binding it up. Wedge the
pedal to the mat and recheck the blade travel.
So now you've got both ends of the range mechanically
ideal, leaving any sensor troubles to be relating to
just that. A stock TB and TPS, if set up clean, should
be able to give you 0.6V at idle and 4.6V at WOT, all
nice-nice.
